Back Bay Sit On Top Kayak

Posted on August 24, 2015 by ChrisOstlind

A Modular System Approach to SOT Kayak Sailing, Paddling and Mirage Drive Propulsion

Sit-On-Top (SOT) kayaks are easy boats on which to learn to paddle. They have none of the “get in the coffin and you are about to drown” psychological identity that one finds in the Sit-Inside boats and they’re amazingly adaptable to a wide range of paddling activities. It also doesn’t hurt that they are pretty straightforward boats to rotomold, which makes them very cheap to produce in large numbers.

I didn’t envision just one boat for this niche in the home-built kayak market. Instead, it came to me that there would need to be at least three models that could address the wide-ranging styles of boating interests in this area of the kayak world. The result was a couple of very clean, SOT models at 14’ and 16’ called the Corona and the Back Bay, respectively. The third model was going to be called the Wahoo, as it was specifically designed for the folks who spend a lot of time fishing with their SOT’s. I’ll get to the Wahoo in the next article.

As a canoe and kayak sailor and a guy who had just been out for a test drive on the Hobie Adventure Island, which is based on their 16’ SOT Adventure model, I wanted to offer my own take on what makes for a truly fun and stylish, sailing SOT kayak. The result was that a fully integrated system of component parts was designed for the basic Back Bay. This modular approach allows the Back Bay to go sailing by simply adding a system of light-weight, easily built elements that quickly convert the SOT to a single aka sailing boat called the Scorpion, OR, to a double aka sailing boat with slightly larger ama volume, called the Doubloon. Of the two configurations, the Doubloon is most like the well-known and highly respected, Hobie Adventure Island.

The Corona and the Back Bay are virtually identical models, save for their respective lengths. For the purposes of this article, I’ll focus on the Back Bay version and all the potential add-on systems I’ve incorporated in the design.

THE BACK BAY SOT KAYAK

Specifications:
Length overall – 16′
Beam overall main hull – 28″
Depth of hull max – 12”
Weight – 48 lbs. or less
Displacement – 335 lbs.

This boat is built in the S&G style of construction in 4mm marine ply with 6 oz. plain weave fiberglass set in epoxy on the inside and outside of the hull for full laminate sandwich strength. The build process uses external cradles as building supports, ensuring that the hull goes together with minimum hassle when handling the rather slender and longish hull panels. The boat is bulkheaded internally at three key points. These bulkheads create not only integrated strength in the design, but they also cleanly separate the hull cavity into four unique volumes for gear storage and watertight flotation.

The Back Bay can be configured with a large, open tankwell set aft of the cockpit, or built with a watertight, aft hatch cover for internal storage in a conventional kayak style.

Specifications:
Beam overall – 10′
Weight (est.) – 90 lbs.
Sail Area – 56 sq. ft.
Displacement – 350 lbs.
Draft (board down) – 28″

The Scorpion variant is a Sit-On-Top design for fun sailing, paddling, or Mirage peddling… or all three, as the builder desires. There will be a design for a leeboard mount included in the plans for those who are going to build the boat for sailing. Having the aka gull wing form set well forward permits a full paddle swing arc. The aka beam connectives to the amas is split into a pair of mounting elements. I did this to make for a stronger, single beam mounting struture. With a single beam design, there is a tendency for the am to want to rotate around the beam, making for a very stressed component that could lead to early failure. By splitting the beam and spreading the mounting points, I have given the structure more resistance to this rotational force, making for a more rigid boat in use. This setup will allow the owner to power sail in light air with both the paddle and the sail providing thrust. With the leeboard swung down for sailing, the owner can do some “power sailing” and utilize the Mirage drive, as well as the sail, in light conditions. The Mirage is capable of boosting boat speed enough that it creates apparent wind over the sail, adding power where there really isn’t enough for sailing alone.

The amas are positioned to optimize capsize resistance when sailing off the wind. The amas do not touch the surface of the water at rest in stable trim and provide only minimal wetted surface drag when underway by paddle or peddle. As soon as the sail is loaded by the breeze, though, the ama on the lee side begins to immerse, firming-up the boat and resisting the heeling moments being generated.

The aft deck can be configured as a watertight hatch with full access to the aft sections of the hull, OR a large, diving tank well with self-draining ports. The cockpit is fitted with self-drain ports under the seat as well as forward, in addition to the daggerboard slot. There is a watertight deck plate just forward of the seat, between the knees of the sailor/paddler to provide secure storage for critical items that may be needed on a routine basis. The foredeck has a watertight hatch cover for bow storage needs.

The rig is a fully battened Dacron sail with two reef points and a multi-section, self-supporting mast which steps into a sealed mast socket in the hull. The mast and boom sections can be aluminum or carbon, as budget permits. The sail choice is open for the customer as long as it can be balanced with the fixed positions for the mast and dagger board. The Cunningham is run to the deck of the gull wing aka to keep the rig on the boat in the event of a capsize.

With 56-sq. ft. of sail on a 90-pound boat, this will be a decently speedy boat without being in over its head all the time in a stiff breeze. I suggest two reef points in the sail to allow for sailing in a wide variety of conditions.

This will be a wet boat at speed, yet there are no worries at all for flooding and sinking, save for a truly nasty trip over a reef that shreds the entire underside of the craft. The bow, cockpit and aft hull volumes are all independent, sealed compartments, as are the ama volumes.

Reentry from a swimming session will be easy with a simple, sling, or rope ladder much like those used by rock climbers, called etriers.

Sliding foot pedals in the cockpit control the rudder. The rudder flips-up when it encounters an underwater obstacle, or when beaching, returning, due to bungee tension to the deployed position once past the obstruction.

The boat is constructed in a multichine, marine plywood style with epoxy glass laminates inside and out in a stitch and glue style. Stainless T-Nuts are embedded in the hull deck surface from below to provide a secure set of mounting points for the aka wing. The amas are held in place on the aka tips by large bungees and a notched lock system. This system provides for quick setups on the beach.

You just fit the aka to the foredeck, insert four, 1/4″ threaded stainless screws with comfortable, knobbed grips and screw down the aka wing. The amas slip onto the ends of the aka and you lift the pair of 3/8″ bungees up and over two raised hooks on the aka ends to secure the ama in place. Simple, easily maintained and near foolproof in operation.

DOUBLOON SAILING SOT

The Doubloon is the second variation on the central SOT theme of this group of boats. In this design, I am looking to provide a more expansive utility application for the base, Back Bay SOT version. The Doubloon is essentially a solo craft and it carries the same, 56 sq. ft. sail, but the overall potential of the boat is expanded through the use of dual akas and full trampolines on both sides of the Back Bay hull. The rendering of the Doubloon shows a daggerboard inserted down through the Mirage Drive trunk, but in use, I would prefer to have the board mounted outside the Back Bay hull as a leeboard. Plans will be supplied with the leeboard solution.

The akas on the Doubloon are spaced to allow for a full paddle stroke with the boat setup as a trimaran. There are two sections of tubing that span the opening fore and aft between the akas from which the tramp is mounted. The trampolines are designed to roll-up on the outer tube section, much like a window shade and they are deployed by an endless loop of light halyard line. With the tramps fully deployed, the inner tube section lifts up and over a holding pin in the aka and the sailor applies as much tension to the tramp as he feels he needs by hauling-in the endless loop line and cleating it off. If a paddling session is desired, he simply pops the jam cleat and pulls the line to roll-up the tramp on the outer tube section. This procedure applies for both port and starboard tramps.

Like the Scorpion, the Doubloon can be built to utilize a Mirage drive in the center well and the need to roll-up the tramps for paddling is essentially negated, (though it is nice to have the option once in awhile as Mirage drives can be difficult to maneuver in tight places)

The aka beams are held to the deck of the Back Bay hull with the same, threaded knob strategy for quick setup and takedown times. Similarly, the amas are held to the aka ends with hefty bungee cords for the simplicity of use. There’s another, rather invisible, benefit to using the bungee cords for ama mounting. Because they are being held in place through a fairly dynamic hold-down system, the amas can move about, ever so slightly, while underway. This allows the amas to have some structural “give” and the result is that the banging and thrashing that is typically experienced by the ama, is somewhat dissipated through the flex of the joining system.

The design similarities to the Hobie Adventure Island are obvious. This boat, however, should be just a bit faster in the water, mostly because it will be much lighter than the rotomolded Hobie. For that same reason, it will also be easier to put it up on a roof rack for transport to the water and a lot easier on the back when you have to take it off the car to store it at home. The Doubloon configuration allows the sailor/paddler/peddler to bring along extra gear, which can be lashed to the tramps in waterproof bags. They can also take along kids, or perhaps someone special, who could lounge out on the tramp surface while lazily sailing along for a sunset cruise on a warm summer evening.

All in all, I think the Back Bay SOT should be a really fun boat to own for warm water/warm weather boating adventures. It has the capacity to carry enough gear for several days out on the water. When rigged with a sailing system of your choice, it can also cover some pretty good distances if the winds are favorable. Plans for this boat and all its variations will be available from this site and Duckworks Magazine.

Chris Ostlind

Lunada Design
Chris@Wedgesail.com

NAGARE 21′ AND 17′ MIRAGE DRIVE SPEEDSTERS

Posted on July 10, 2015 by ChrisOstlind

Making use of Mirage Drive propulsion with more efficient hulls designs

Nagare 21 Bow Obl w

Nagare (nah-ga-ray) is a Japanese word meaning Flow.

The two boats in this group are 17 and 21 feet in length and are known simply as the Nagare 17 and the Nagare 21. Both designs make use of the popular Hobie Mirage drive for principal propulsion with the 21 footer Nagare 17 bow obl w being a double Mirage setup and the 17relying on a single Mirage.

Both of them are configured as trimarans with fairly small and unobtrusive amas designed to give the boats remarkable stability in a wide range of conditions while allowing the vaka, (main) hull to be decidely slender for more effective drive through the water.

The Nagare sisters also have incredibly narrow waterline beam numbers that, when coupled with their fairly long hulls provide for very easily driven hull forms for high efficiency per unit of energy applied.

I expect both boats to operate at the very high end of commercially available paddled boats of the same length, beam and weight. So, yes, they can go pretty quickly, but that’s not the real purpose.

The real benefit of the design genre is through the ease with which they are propelled at any given speed, compared to other boats of their size. This efficiency translates directly to those using the boats as less tiring for miles covered, or greater speed with the same effort as other, wider designs.

Because the propulsion is derived from the largest muscles in your body, the leg muscles, rather than the arms and shoulders, there will be less fatigue for each mile traveled. Because leg muscles are so much bigger than arms, they will be able to do more work in a given period of time, making for longer possible trips, as well as the mentioned lower fatigue issue. With a less fatiguing effort, more people will be able to enjoy the experience of being out on the water for daylong adventures.

NAGARE 21 DOUBLE
SPEED AND STABILITY FOR DOUBLE RECREATIONAL BOATERS

The Nagare 21 uses a set of amas, mounted on a pair of simple, anodized aluminum tubes with quick release snap buttons holding the sections together for easy disassembly for car-topping. If a trailer is used to transport the boat, the beam of the Nagare 21 falls well below trailer maximums, so nothing special needs to be done to take the boat to and from the water. Two Nagare 21’s can be trailered, or car-topped, by removing one of the amas and placing the main hulls close to one another on the racks, or trailer. The removed amas easily fit inside the hulls and they are ready to go. The whole affair on the rooftop is very much like a pair of sea kayak doubles. Because of the length, I would not mount a boat this big on any compact cars. You would be very likely to rip the rack right off the roof in strong side winds.

Steering is by means of a simple, flip-up style kayak rudder with control lines run through the hull to a convenient steering lever in the cockpit. I suggest the SeaLine SmartTrak rudder system (do a search for supplier), the P-41 Multi-purpose rudder from Onno Paddles http://www.onnopaddles.com/onnocomponents.htmland the Feathercraft rudder system for hardshell boats. http://www.feathercraft.com/accessories/rudders-hardshell.php These are really great rudder units and will give excellent steering control with minimum drag.

NAGARE 21 SOT OPTION

This boat can be built with a full cockpit tub so that it functions as a Sit-On-Top kayak with full drainage through the Mirage drive openings. Auxiliary drain ports are located in the tub for rapid removal of any water that comes in over the side of the hull. I suggest the SOT option for warm water users, with the more traditional kayak style, Sit-Inside hull form for those who will be using the boat in colder water, or more frequent inclement weather.

The SOT version has internal bulkheads for support of the SOT tub, along with the capability of adding a small circular deck plate for an additional watertight compartment in the cockpit that is perfect for small items, such as cameras, wallets, car keys, etc.

The SOT variation is an optional element to the base plans. If you wish to built it as an SOT, drop me an email at my regular email address and I’ll get back to you.

ROUGH WATER USE

This is not really a boat that is meant to go out in rougher conditions, such as those where a full-blown sea kayak might be right at home. It’s meant for quieter waters, such as lakes, bays, harbors and bigger rivers. It can take a session in 1 or 2 foot breaking surf, but I would not expose the boat to bigger waves, especially in a shore break scenario. You may find yourself out from the shore a bit when the wind comes up, producing steep, choppy waves. The basic Nagare 21 will handle this easily because only the cockpit will be exposed to swamping. The amas will keep the boat stable while you pedal to shore, or a quieter place on the water, where you can bail-out the boat and continue.

It is a perfect boat for sightseeing, bird watching, fishing, photography, and just simple, energy efficient cruising with near bomb-proof stability (you can stand up in the boat while out on the water without your partner coming completely unglued, for instance).

The Nagare 21 is a fast, comfortable and unique boat for a couple who like to get out on the water, but do not want to hassle with the business of capsize that is present in other types of boats, such as kayaks and even canoes.

NAGARE 17 SINGLE
A NEW STYLE OF SOLO BOAT FOR TROLLING FISHERMEN

The solo version of the Nagare series has some very different twists, compared to its bigger sister. It has the same, highly efficient and easily driven, slender hull technology, the same set of trimaran style amas well aft for big time stability, the same generous cockpit opening and the same convenient utility for car-topping or lightweight trailering.

The design elements that set this particular boat apart from its sister craft is that the Nagare 17 has a very special capability when it comes to fishing.

AFT FACING TROLLING

Anybody who builds the Nagare 17 and intends to use it for fishing will probably be knocked-out by the potential for facing aft while trolling. Imagine using your legs to quietly drive the boat forward while you casually set trolling rigs, eat a sandwich and keep an eye on the fish finder… all while keeping an eye on the rigs you have set, with them easily at hand?

This is the signature utility development with the Nagare 17, designed specifically, for fishermen. It works like this…

The fisherman loads his boat, drops into the forward facing seat, hits the iPod for his favorite tunes and jams out across the lake at a remarkable speed for a human powered boat. He zips across the lake in virtual silence because he’s driving a very skinny and efficient hull with no engine sounds. Once he arrives, he’s going to make a few sneaky trolling passes with his Mirage drive pushing him along over that monster crew of Pike that are hanging around on their favorite piece of structure. Wham! Fish On! and the day starts with smile on his face.

If you’ve ever fished from a typical Sit-On-Top, you know that you have to face forward while trying to look over your shoulder while trolling. Hook-up and then you have to swivel around, grab the rod and go after the fish. All the time you are doing this, you have to balance the boat carefully, because the whole tamale could go over and end your day right then and there.

Well, that’s how you used to do it, anyway.

With the Nagare 17, you can take it to a whole new level of fishing pleasure. The Nagare 17 is equipped with twin Mirage drive trunks. When driving the boat forward and facing forward, the Mirage drive is dropped into the forward trunk and a tractor-style seat is dropped into the aft trunk with the seat bottom resting on the top of the trunk.

To convert the boat to aft facing trolling and fishing, you simply stand up in the boat and swap the Mirage drive for the aft mounted seat plug and the seat then goes to the front trunk… facing aft. With the Mirage drive still set to drive the boat forward, you simply sit down and start pedaling, slowly, up to your desired trolling speed.

Now, you can watch your fish finder, GPS and your trolling rigs while you continue to tool along at your favorite speed for nabbing the fish. Get one on and simply work that rod while continuing to face aft. No twisting around in your seat, no ”just about dumped it” scenarios, just simple, fun fishing in a very stable boat. What could be cooler than that?

With the fore/aft balance point of the boat set right between the two drive trunks, there is but a very minimal change to boat pitch when you change the direction you face.

The Nagare 17 is further designed to accept an insulated and watertight tank between the two aka tubes where they run through the aft deck. You can use this for all kinds of stuff like: your catch, fresh bait storage, cold beverages if you catch and release… whatever suits your needs. There is plenty of room between the two drive trunks for a pretty good sized tackle box and lots of room up forward of the trunks for any of that “other stuff” that fishermen seem to sneak aboard their boats.

A moveable electronics unit can be fastened at the forward end of the cockpit, or unhooked and moved around aft if you’d rather have it facing that way.

Maybe you want to cast lures or flies instead of troll. The boat is so stable with the two, wide set amas, that you can stand up and cast all day without ever feeling like you are getting the least bit tippy. All in all, the Nagare 17 is quite a boat for fishing, as well as just plain fun, recreational pursuits.

The Nagare sisters represent a unique design family for human powered vessels. They are quick, stable and with their unique styling, represent a distinct departure from the looks of traditional boats one typically sees on any given shore or launch ramp. Both boats are designed to be built in marine ply Stitch and Glue methods for the hull sections, with cedar stripped decks to take advantage of the really beautiful, smooth curves capable from that style of building. You can paint the lower sections of the hull and leave the cedar decks natural with a deep varnished finshed, for a real knock-out boat that will really gather a crowd.If you really want to have a plywood deck build instead of the cedar strip build, write and twist my arm gently. I can design that change for those who really like to build that way

Plans are not yet complete, so if you would like to build one of these two boats, please send me an email and I’ll put your name on the mailing list for information, or watch the plans section of Duckworks for the notice.

CHRIS OSTLIND
LUNADA DESIGN
CHRIS@WEDGESAIL.COM

Largo… An SUV for the Water

Posted on May 29, 2015 by ChrisOstlind

Fuel Efficient Power Boating For a New Economy

I’ve been getting a significant number of inquiries for the power version of my Gato Especial sailing cat. I let it slip out, some time back, that there would be an engine driven version coming along, but time got away from me and so, the project sat idling on the design table.

I’m kind of drawn to cars and boats that can solve a host of utility needs, as well as provide a comfortable, transportation experience. I’m about to sell my venerable Toyota Landcruiser and get myself into something that makes a lot more sense when it comes to utility and fuel efficiency. As a result, I began to think of a motorized version of the Gato platform as a Crossover/SUV type of vehicle with a big interior volume aft of the helm station and truly fuel-efficient engines to complete the picture.

The new boat would have a stand-up position for the driver with a sliding, deck-mounted seat that would allow the skipper to sit while steering. There would be a huge deck surface behind the helm for all sorts of seating and/or gear carrying options. The new boat would have a tailgate/liftgate setup for ease of loading. The new design would have a big storage space forward of the helm for the odds and ends that always end-up on a boat. Power for the initial design would be from a pair of four stroke outboard engines for redundancy, as well as beneficial weight distribution.

Largo HT Gates Open aft obl 5x7

On a personal level, I am attracted to design concepts that deliver a responsible set of solutions for this new economic reality in which we all live. I like the term, Crossover, which is openly lifted from the automotive industry, as it touches on the realities we will all face in the coming years. We are headed to a time in which our vehicles will need to do more than just give us a sedan in which to cruise around, or a truck to do our dirty jobs.

In the world of cars, the Crossover approach has created vehicles that live in the niche right between the heavier, clunkier, SUV’s and the typical, everyday passenger car. Similarly, with this new design, I was looking to take the slot right between the generously proportioned sport cruisers you see at marinas all over the world and something like a cleanly drawn work boat. I wanted some of the people driven touches of scale and fit/finish, while being able to morph from one working task to another as a truly useful, all-around watercraft.

The result would be my take on what a boat should look like which is much more fuel-efficient and less expensive to build and transport. It would provide a very high degree of utility and, of course, it would need to be wrapped in an aesthetically pleasing package.

The aesthetic, design component is pretty much a subjective thing, but the fuel-efficient aspects are a design process that combines easily driven lightweight hulls, drive systems with high economy for delivered horsepower and a significantly reduced aero drag signature allowing the boat to just slip through the air.

I’m of the opinion that I have reached all the basic design criteria with this new design, The Largo.

Yeah, sure there’s a distinct connection to the Bond films, Thunderball and Never Say Never Again, with the bad guys both being named Largo. Beyond that, Largo is also a direct take on the ’48 Film Noir thriller with Bogey, Bacall and Edward G. Robinson. It is also, the well-known island in the Florida Keys where boating adventures await in every direction and one of my favorite adventure boating events, The Watertribe Everglades Challenge maintains its finish line.

Largo Specifications

LOA 21′
BOA (trailer legal) 8′ 6″
Height 6′ 5″
Displacement 2000 lbs.

Suggested engine package is Twin 9.9 hp four stroke outboards. It may not seem like it from the renderings, but plenty of interior volume has been worked into the design to allow full movement of the engines from side to side

The aft cabin space of the trimmed-down version will have the potential for a huge, manual, slide-back sunroof for a full open-air effect in the main cabin volume, as well as large side openings for breeze and visibility. The side openings can be fitted with removable, semi-structural soft windows for better streamlining and also for inclement weather.

Way back at the aft end, the boat has a floor level, drop-down tailgate, as well as a glassed, liftgate. I see this as a utility benefit when the boat is beached, bow out, in a marina slip. The tailgate will allow easy loading of gear and anything else that might be shoved in the back of this boat while it is still on the trailer. It will also give a chance to sit on the tailgate and hang out. The entire hardtop can also be removed for a full-on waterborne convertible. Or, if you like, a pick-up truck for the waterfront that can haul a whole bunch of oddly shaped objects, should you have a need for that kind of utility with friends while enjoying a sandwich or cold beverage.

The suggested engine package is based on need. If the owner wants to cruise with high efficiency and still be able to bang out 11-12 knots when he likes, then a pair of Yamaha Hi-Thrust 9.9 hp engines will do the trick. The engine setup can be equipped with remote starting, steering and power engine tilt. They both have pretty healthy alternators to keep any onboard electrics going, so lighting, navigation and radio systems can be easily powered-up.

Cutting edge enthusiasts will ditch the outboards and equip the boat with a bank of batteries under the deck in each hull and a pair of powerful electric motors that drive a set of matched, counter-rotating props. As an alternative to the twin outboards, this boat, so equipped, will silently cruise with a pretty decent range and be able to go to full power instantly whenever the owner wants the buzz of the electric drive potential.

The hulls of the Largo are exactly the same as those of the Gato Especial sailing cat. They are 10-1 in Length to Beam ratio at the waterline and will be very easily driven while still providing a respectable displacement payload. The is a spray chine on the inside and outside of each hull to direct wave action away from the boat while underway, as well as reduce drag on the hull. At cruising speed, a small amount of hull lift is also a side benefit of the spray chines.

The aft end of the hull bottoms is relieved with a slot to allow engine placement forward of the typical transom mounting and to allow the power tilt capability to raise the props well clear of the hull bottom for beaching and trailer loading/unloading. Moving the engines forward adjusts the balance point of the boat forward and helps with handling and pitching moments. It also puts the engines inside of sound deadening boxes, so the overall noise level is reduced while underway. Cruise the harbor on a warm summer evening with soft music playing on the surround sound system and you can really hear the soft music.

Bridgedeck clearance between the hulls is a generous 17″, so wave slap under the main deck will be kept to a minimum. This raises the overall comfort level of the boat, which is especially nice on a longer trip.

The large deck space inside the boat will make for a spacious camping environment, gear hauling space, or just about anything else you can think of doing with a boat that is this versatile. The tailgate opens to a generous 49″ width, allowing the owner to load full sheets of plywood right through the back of the boat without leaning them up on edge.

The hull volumes below the main deck can also be used for the storage of fuel, batteries, water tanks, anchor, rode, etc. It’s always a good thing to keep the heaviest items on a boat as low as possible to enhance stability and improve ride. The space in front of the main forward bulkhead can be accessed via a large hatch. This is an excellent location for lighter weight storage needs such a sleeping bags, tents, clothing, etc.

A good friend asked if the boat could be equipped with a drop-down front ramp and a walk through windscreen so that the Largo could be driven right up onto the beach to unload through the bow. The answer is Yes… certainly can accommodate that feature with a few changes to the forward structure.

Clearly, the Largo is a boat with a generous latitude of use potential, it draws design cues from a pretty diverse group of sources and sets a new standard for home built power boats with a decided edge towards fuel economy and responsible boating.

Chris Ostlind
Lunada Design

Collage

Posted on May 29, 2015 by ChrisOstlind

Another Trimaran/Skiff … Bigger, With More Power

Well, you had to know this would happen…

When the Montage Skiff/Trimaran was introduced, the Lunada Design website was absolutely flooded with an ocean of page hits every day right after the article was posted. I received several dozen personal query letters regarding the boat and sizeable slice of them were directed at the potential of a bigger version of the Montage.

The concept of being able to build your own boat and rig it with a used mast and possibly even used sails, (if they are in good enough condition) had struck a chord with the homebuilding community. The creation of a larger version of the Montage would take the specified rig choices up into the much more commonly found beach cat rig sizes and make the business of finding a used rig in great shape, a whole lot easier. After pencilling a collection of thoughts and running some rough numbers on the potential, the idea came into focus as the 18′ Collage.

The new boat is very much like the smaller Montage in many ways. The Collage has very similar lines, with the exception that it can be quickly identified by its subtle, reverse bow profile. It has a virtually identical purpose and the same, functional conceptual pragmatism for the homebuilder. The plywood version and the strip-built design both have the same bow profiles. This profile is also applied to the amas of both build styles. I wanted to give the boat a bit more of an aggressive look without taking it too far in the direction of the out and out racing multihull designs currently in vogue.

The ama shapes, especially on the smooth hulled variation, borrow other design cues from the modern performance dedicated French designs of VPLP, as well as the very cool work of Nigel Irens. The transoms are nudged in the direction of a triangular shape, while retaining some of the typical beach cat, flat-topped U-form feeling. The volume concentration is well-forward, with the foredecks being much more rounded to provide rapid shedding of water. These shapes will help to reduce the tendency of multihulls to pitchpole when sailed hard.

Breaking away to some degree, from the single, build style of the Montage offering, the Collage is presented as a fully strip built, smooth hulled version, as well as a multichine plywood version. These choices will give builders the ability to work with the material choices and aesthetics they prefer. I am also looking at the potential for a foam cored sandwich laminate boat using the vertical strip technique, though that iteration will probably come around a little later in the process.

Collage Specs

LOA 18′ ( 5.48 m )
BOA 14′ ( 4.26 m )
BOA main hull 41″ ( 1.04 m )

Sail Area
Main 163 sq. ft. (15.14 sq, m.)
Jib 55 sq. ft. ( 5.12 sq. m. )
Spinnaker 161.5 sq. ft. ( 15 sq. m. )

Displacement 1000 lbs. ( 454.5 kg. )
Weight 380 lbs. ( 172.7 kg. )

The Collage meets all the same design criteria as does the Montage, except it’s longer and wider, has more sail area, carries more crew weight and yes, it’s going to be faster in the right hands. Faster… sometimes this term can be kinda self-defeating when speed claims are made compared to another boat. When it comes to recreational boats, I’m of the opinion that speed is a relative thing based on the overall design brief of the boat in question. In the case of the Montage and Collage designs, speed is one of the attractive elements as long as it is kept in perspective with just what the use application will be from day to day. From where I sit, this will be primarily recreational purposes.

The Sail Area to Displacement ratio ( SA/D ) for each of the boats is as follows: The Montage is 31.56 and the Collage is 34.88 With both of these boats being sailed at near max displacement, I give the nod to the Collage, based on waterline length, as well as the ability to punch through wave conditions that will toss the Montage around to some degree.

I would like to see this pair of boats ( Montage and Collage ) blasting around in the hands of skilled sailors. There’s nothing quite like the feel of a performance boat and the way it can deliver the exhilaration of a spirited ride. But… I’d also like to see this boat out on the water being used by families while they have a really fun day on the water with, maybe, a somewhat toned-down speed blast tossed into the mix every now and then to get the kids chirping.

I’m looking at the potential for the Collage to create a new beach and/or lake sailing culture in which energetic hot shoe dudes, as well as young sporting families, can all mingle on the beach, out on the water and share a communal BBQ after the day of sailing. I grew to maturity on the beaches of SoCal watching the brand new Hobie Fleets do this very thing and it was a lifestyle that perfectly fit my beach kid way of thinking. It would be great to see that happen once again. Could this take place in 2009? Hey, I don’t know the answer to that one, but it is fun to think of the boat and its owners in those terms.

There’s a lot going for the Montage/Collage design approach to support such a social event concept. Both boats are affordable to build, they are easily trailered by even sub-compact cars, they make use of “experienced” parts that can be had on the open market for pennies on the dollar when compared to new parts and they are boats that are easily sailed on the first day. This last part is important, as the boat will attract more enthusiasts when they see that they can be sailed with what pretty much passes for beginner’s skills. Just because it can go fast, does not mean it has to be sailed that way. As the owner’s skills grow, the boat’s potential will be there waiting for him.

As a way of introducing the Montage and the Collage designs to the homebuilder market, I’d like to offer free plans to one person. This builder should be able to show me that they have a very strong interest in either design and are willing to build the boat as I supply the plans in accordance with their progress from the previous plan set delivery.

If interested in this offer, you can write me at: Chris@Wedgesail.com or at lunadadesign@gmail.com and make your pitch. The one chosen to receive the free plans will be willing to provide construction photos of their progress and a brief written description as to how things are going. The personal accounts will be published on this website, Lunadadesign.net so that the readers of the site can follow the projects.

Chris Ostlind
Lunada Design

Montage

Posted on May 29, 2015 by ChrisOstlind

Family Oriented Trimaran/Skiff With Performance

I’ve drawn a lot of small trimarans in the last seven years, beginning with my A18 for performance coastal cruising. During that time period, there has been an explosion of other small, daysailing trimarans on the market. Several years ago, a new trimaran/skiff hybrid was introduced from a clever group of guys in New Zealand called the Weta. www.wetamarine.com

This boat created immediate appeal to beginning and intermediate sailors. It offers much of the speed experience of a high performance skiff in a stable and predictable platform that is really tough to capsize. The Weta is one of the first boats to encourage family participation and reintroduces the waterborne fun of the beach sailing culture, established way back in the late 60’s with the intro of the Hobie catamaran.

A brand new, factory built Weta goes out the door for USD $11K. Realistically speaking, this isn’t an in surmountable amount of money for a factory produced, brand new carbon trimaran. It is, however, quite a lot of money for most casual recreational enthusiasts and the folks who like to build their own boats… especially when you consider the rugged economic conditions we all face these days.

So, I decided to take a whack at producing a set of plans for a homebuilder’s version of a Weta-like hybrid
that could be Montage aft up w buildable in the neighborhood of $5600 ready to sail with a new mast, sails and trailer. I’m calling the new boat Montage, as it is an assemblage of concepts that fill the slot between a performance skiff and a small, quick trimaran. This boat will appeal to sailing enthusiasts from kids to codgers who just want to get out on the water and have a fun and fast experience without breaking the bank.

The estimated $5600 figure represents a boat with a whole host of brand new parts. For the clever builders out there, the Montage could be even less expensive if they can find a used 470 rig, perhaps a used small craft, or beach cat trailer that could be modified to fit the hull design and even a collection of hardware in good condition. The Montage is a very light boat at right around 235 lbs., so you do not need to buy a heavy duty trailer.

After a dozen different sketches of boats that fit the general design motif, I settled on a plywood multichine hull design that had virtually the same dimensions
as the manufactured version. When I projected the hull panels to a two dimensional layout, though, I saw that I was going to be wasting a good bit of plywood by going with a 14′ 5″ boat that mimicked the dimensions of the production version.

I went back to the drawing table and reconfigured everything so that the longest hull panel was going to just fit on a couple of sheets of marine ply laid end to end. The main hull also got just a bit wider in the process of lengthening the boat. Where the factory boat uses carbon fiber on foam cores for its structure, the Montage will be a 4mm marine plywood design with full fiberglass/epoxy sandwich laminates inside and out. The foredeck and the cockpit seating transitions are strip-built in Red Cedar to give the overall appearance of the boat a smoother, more organic feel than straight plywood panels.

The amas for Montage came from a 16′ trimaran design that I had already done and required minimal re-design to work with this boat. The amas are also designed as multichine ply forms with pretty high volume shapes well forward and a water shedding deck form that will helps to keep them riding high even when driven hard. Ama displacement is 100% of the all-up boat weight when sailing.

Montage Specifications

LOA 15′ 6″
BOA 12′
BOA main hull 41″

Main 110 sq. ft.
Jib 38 sq. ft.
Screacher 102 sq. ft.

Displacement 650 lbs.
Weight 235 lbs.

The aka beams are anodized aluminum instead of carbon tubing. The inboard ends fit into fairly burly sockets in the hull and are held in place with quick release pins. Flat deck flanges on the ama ends are welded in place and bolted to the amas. The amas are removable from the aka tubes for repair or maintenance, but otherwise stay mounted, along with the trampolines, as complete units.

The mast is also anodized aluminum. The boat uses the same mast section as the 470 dinghy, which is a Proctor Cumulus section. This mast is available on the used market with a little bit of hunting around. If you want it all and have the money, then there’s a very cool, filament wound Forte carbon spar available with very close specs to the Proctor that will rock your world. http://fortecarbon.com/

Making these two changes from the benchmark, all-carbon Weta to an aluminum spar and tubing keep the costs down, with but a slight weight penalty over all-carbon parts. If you find a used mast, the savings will be even more substantial.

The mainsail and the jib will be built in Dacron instead of a more expensive fiber/Mylar laminate sail. The jib is a self-tacking blade. The main is a boomless design, which will keep head bonking incidents out of the picture while sailing. The screacher is furled from the bowsprit for simple convenience.

I have found that the more expensive sailcloth laminates are capable of driving the boat just a bit faster, but for the average recreational sailor, they will hardly ever make a difference compared to more forgiving sails in Dacron. Dacron is much easier to maintain, lasts longer, is a lot more tolerant of UV exposure and can be repaired by any sail loft wherever you go. If the builder of the Montage really wanted to, they could buy a set of sails in something like Pentex laminate instead and they’d have that hot, performance boat look that some desire along with just a bit more zip under sail.

The overall design of the foils and their operation is pointed directly at the needs of a recreational sailor. The boat uses a centerboard for ease of use
and pretty much no-brainer beaching. Likewise, the rudder is a flip-up style unit that eliminates the problems of hitting underwater objects. The foils will be built with template shaped cedar cores having a white ash stringer for stiffness and then glassed for durability.

The aluminum aka tubes will be sold pre-bent and ready to install on the amas. If the builder has access to a good mandrel bending facility that can handle the OD/ID specifications of the tubing, they can fabricate their own tubes to supplied specs.

The Montage is designed to be a really fun day sailing machine that can generate near performance skiff sailing speeds while offering a hugely stable platform for recreational sailing. Construction of the boat is very straightforward in marine plywood with glass/epoxy laminates and can be easily built by any sailing enthusiast who has household handyman skills with tools. The Montage has been created to offer homebuilders an opportunity to enjoy this style of family sport boat at a completed cost that is far less expensive than the manufactured version.

CHRIS OSTLIND

Lunada Design

FRESH TAKE ON THE SOLO16 S

Posted on May 28, 2015 by ChrisOstlind

A safe, speedy solo cruising craft for adventurous souls

After a lot of input from readers of this site, I have completed the modifications to the Solo16 S design that reflect many of their
expressed interests.

The Solo16 S now has a bit more displacement as a direct response to suggestions for the use of a small 2 hp outboard and some spare fuel. At the same time, the vaka hull was given additional beam above the waterline and the shear was raised some to allow for mods to the amas.

The amas, themselves, were made slimmer and taller, while retaining the same volume. They now have a slight vee section which gives the boat a progressive resistance increase as the amas are pressed heavily in a gust.

To complete the changes, a sporty all-weather soft cabin has been designed to allow the owner a chance to sail in a wide spectrum of conditions. The new cabin is modular in its approach with the ability to address a multitude of sailing situations.

There is a folding dodger setup forward with a large PVC window for full visibility. A removable Bimini top extends aft, covering the entire cockpit from rain and a relentless sun. Side panels can be put in place as needed to protect the crew from hard spray, or to further enclose the cockpit. A reversed dodger is positioned at the aft end of the cockpit completing the full cabin system.

All panels except the Bimini have generous window areas which are backed by micro mesh screen that is small enough to keep out the No-See-Ums. The PVC windows are zip-out removable and the screens can be rolled-up for maximum airflow through the cockpit. The complete enclosure system allows the owner to mix and match the panels as needed for the best protection from the elements.

The Solo16 S is a lightweight, trailered boat with demountable amas. The aka beams stay mounted to the amas, along with the trampoline surface. The aka ends fit into composite tubes which are bonded to the vaka hull and the side hiking platforms.

When setting up the boat for sailing while on the trailer, the owner simply lifts the ama assembly, rotates and places the ends of the aka tubes into the matching vaka openings and slides the ama into place. The akas are fully seated when their internal, spring loaded snap-buttons click into place. The entire ama assembly is easily handled by one adult with modest physical strength.

In the trailering mode, the complete boat does not exceed 68″ (1.7 m) in width, falling well under every trailer width limit in the world.

Chris Ostlind

Lunada Design

Neo 21 Sliding Beam Catamaran

Posted on February 28, 2015 by ChrisOstlind

Modern design, enhanced stability and creature comforts, along with remarkable utility make for a stunning trailerable beach camp cruiser for passionate multihullers.

Hobie Alter introduced the Hobie 16 catamaran in 1969 and the sailing world, as it was known, hasn’t been the same since. In 1992, with many of the beach cat lifestyle crowd having families of their own, the Hobie Cat company introduced a new boat called the Hobie 21 SC (Sport Cruiser) that was aimed at the more leisurely needs of beach cat cruising, rather than the well-known, hull flying beach cats.

The 21 SC was, as you might guess, 21′ in length. As a fixed beam design, it was limited to the typical, US trailer legal width of 8’6″. It featured a built-in cooler, an outboard mount and it had a 29′ mast carrying 222 sq. ft. of sail area (main and jib). The Neo 21 is designed to accept rigs from a wide variety of beach cats making for a reasonably easy job of obtaining a really good used rig for the boat. This feature, alone, will make for a very economical boat to build.

The design calls for a main and jib rig between 218 sq. ft. and 250 sq. ft. (20.26 sq. m. – 23.22 sq. m.) You can go bigger than that and no doubt some will, but you’re on your own. The larger rigs may require an adjustment in the placement of the daggerboard, but that’s about it.

Getting away from the discussion on how big of a rig can be run on the Neo… I wanted to explore the potential of a cruisy-style beach cat that would be more stable for a young family. The Neo and its collection of studied variants, has been in development, off and on, for the past couple of years. The Neo is much more about spirited cruising potential than it is about shredding up the local waters with all-out performance, as one would typically see from a big beach cat with a high performance rig. The boat, while sporting a fairly wide, 11′ stance, is also carrying more weight than a typical performance cat of this length. Slightly heavier, yeah, but the Neo will show a very nice turn of speed, to be sure.

There’s a faster boat hiding within the base philosophy of this concept, but it’s going to be coming along a bit later and it will have a distinct set of design rules for a much different purpose.

The typical beach cat tends to suffer from a small collection of problems that make them somewhat less than desirable for coastal, camp-cruising type applications and a full day on the water with no breaks.

At the top of the list of things that could be better are the issues of:

Low bridgedeck clearance, which is the primary cause of slamming in a choppy seaway.
Fixed primary stability that is a lower design priority compared to the go-fast regime at which they excel.
Restricted leg placement arrangements while seated on what is normally a flat hull deck and adjoining trampoline surface.

The design of the Neo 21 addresses each of these basic issues, as well as solving a few additional problems, making for a really fun, fast and stable beach style cat for coastal cruising and camping.

Bridgedeck clearance

When cruising at more sedate cruising style speeds with both hulls in the water, the bridgedeck clearance of the typical beach cat is decidedly lacking. Beach cats have less clearance because the hulls are drawn to be as small as reasonably possible. Hulls with minimized surface will reduce aero drag when the windward hull is flying. Smaller hulls will also weigh less than those with higher volumes and exposed surfaces. Lastly, when you get the windward hull of a beach cat up in the air, any concerns about slamming wave tops with the trampoline deck tend to melt away.

Cruising style cats are not meant to fly the windward hull, save for very controlled circumstances. As a result, the Neo hulls have been increased in height over other 20-21′ beach cats to provide 16 inches of bridgedeck clearance. This will significantly reduce pounding in choppy conditions and at the same time, provide a much drier, more comfortable ride. Comparing the hull height of the Neo 21 to that of a Hobie Miracle 20, you can clearly see the difference in water level clearance.

Striking a balance between the typical big beach cat and some other cats with much more flared hulls, the Neo experiences a bit of both design advantages by having mildly flared hulls as a key element of their design.

Because the hulls are not meant for sleeping quarters, or sitting within, the flare angle can be kept down, reducing the effect of wetted surface drag when pushing through a seaway. Similarly, because of the mild flare, the Neo has a lot more reserve buoyancy than a beach cat. In real terms, this means a boat that will be able to strongly resist the tendency to want to bury its leeward bow when pushed hard, or when taking a surprise gust. Not only will the skipper of the Neo 21 get more time to take action to avoid a pitchpoling incident, but he’ll have more of a safety cushion to stay way from the scenario in the first place.

Cautionary Timeout: There isn’t a boat out there that can’t get tossed by wild conditions, or poor seamanship. If you decide to build the Neo 21, you will need to observe and respect all the same danger points of sailing to stay upright and moving towards your destination. Even though the Neo 21 is capable of filling many of your boating dreams, it is not a magic carpet that can get you out of any jam you manage to ignore too long.

Let’s face it, one of the really great advantages of having a multihull, is the speed benefit over a monohull of the same size. The Neo design presents an attractive hull design that is decidedly cruising oriented while retaining the key aspects of outstanding performance under sail, or motor. Just as important is the aesthetic impression of the Neo hulls. They just look fast… even when sitting at anchor.

There’s more, though, to efficient boat performance than the design of the hulls. One of the key elements to overall performance and truly good upwind sailing potential is the efficiency of the jib. Jib efficiency is very closely tied to the tension of the forestay and the issue has to be addressed specifically for beach-style catamarans.

Bigger cats place a large beam at the bow and equip it with a seagull striker to maintain high levels of forestay tension. While the Neo 21 is equipped with a beam at the bow, it is as much there to provide a nice taught forward trampoline perimeter, as it is to help with forestay tension. The real power behind the forestay tension on the Neo is obtained through the central pod, which runs the entire length of the boat.

The Center Pod

The single most striking design element of the Neo 21 is the center pod, which extends from the bow of the boat at the forward beam, all the way aft, to just past the aft beam.

For the past several years, many of the high performance, Decision35 racing catamarans on Lake Geneva, Switzerland, have been built with these centerline pods and I found the potential to be very advantageous for the applications I had in mind for the Neo 21.

Much like the ultra high-tech, D35 cats, the center pod on the Neo performs a number of design, structural and utility tasks for the boat, not seen on other beach cats of this type. This pod acts as a structural beam fore to aft and provides solid fixing points for the sliding beams that connect the two hulls. The center pod also allows for the rig to have a very taught forestay, which properly shapes the leading edge of the jib for much better pointing upwind and sail shaping. Because the pod absorbs a good deal of the compression loads of the rig, it serves to lessen the compression loading on the main beam. The smaller total load on the main beam allows for the removal of a dolphin striker from the engineered beam, allowing for faster setup and take-down times on the launch ramp.

Above the deck, the trampoline deck volume of the pod serves as a storage compartment for the anchor and ground tackle while cruising and also provides a really nice back support for sitting out on the forward tramp surface. Well aft, the pod provides a very strong, outboard engine mounting point behind the aft beam sliding structure.

So, is this just a case of, “Hey, why not just build a trimaran?”

Not in my opinion. The pod is significantly smaller in height, as well as beam, than any trimaran hull might be for a boat this size and is very easily and quickly constructed. The application benefits of the form far outweigh the time, money and weight to include the pod in the build of the Neo 21. I see the pod as a clever means for spreading the powerful loads of the mast, as well as a way to comfortably keep the entire boat aligned while spreading, or compressing the beam at the launch ramp. The center pod is not a principal flotation form, though it will provide for a decent degree of buoyancy, should the Neo be capsized.

Increased Stability

The Neo 21 is equipped with a sliding beam system for maximum utility. While the boat does fall under the US limit of 8′ 6″ for trailering, the real magic takes place when the sliding system is employed, spreading the sailing beam of the boat out a very stable, 11′ overall. The typical arrangement of a beach cat is a one piece main beam and one aft beam, both of them fixed in length. With some exceptions, this design approach pretty much locks the beach cat into a standard, 8′ +width in order to take advantage of the existing trailering limits in the US without extra road fees. (the European trailer limit is 2.55 meters (8.36′) and in Australia the limit is 2.5 meters (8.2′) )

The images above show the graphic difference between the Neo when it is compressed for trailering and the full beam of the boat ready for sailing. It’s pretty clear from the renderings that this is a much more stable boat than the typical beach cat with its fixed beam. Neo-beam-comparison-2-w-400x300

In place of these fixed beams, Neo uses three structural beam elements. The full width, removable forward beam is positioned at the bow and serves as the mounting point for the forestay, as well as the forward limit of the bow area trampoline surface. The main and aft beams are each made of two, equal diameter tube sections, which slide past one another through fixed containment structures mounted to the deck height surface of the center pod.

The trailering configuration of the Neo 21 is very simple after lowering the mast and removing the rudder system.

1.) The forward beam sections are removed from their half sockets on the inside surface of each hull and the alignment slot in the center pod

2.) the main and aft beams slide past one another in the two containment structures and the hulls slide toward the centerline until the boat is at trailer legal width.

3.)The sliding beams are then pinned in place for trailering and the forward beam tube is bundled with the main sail and boom.

As discussed previously, the standard Neo 21 is designed to use the rig (230 sq. ft. of sail area), sailing hardware and rudders from a donor Hobie 18 . H18′s are available all over the place at near fire sale prices, so the really expensive stuff for a homebuilt boat, the rig, sails and rudder systems, are easily obtained.

I am suggesting that the Neo be equipped with a set of mast stabilizing lines that mount to the mast at the rigging hounds and are fastened on each side of the main beam. There is a gin pole that drops into a socket in the forward part of the center pod that serves as the lever to hoist the mast while the stabilizing lines keep the rig from falling off to the side during stepping. The forestay is used for this procedure with a rope extension that is quickly clipped into place on the forestay shackle. The rope is led to the hand winch on the trailer for the hoist.

Once fully raised, the safety lines are unclipped and fastened to the mast and the forestay is shackled in place. This is an easy, simple method for mast stepping that has virtually no danger of getting out of control and can be done by one person, if they are strong enough to safely move the mast into the correct position for stepping.

The hull pans and the rounded deck surfaces of the Neo are strip built in Western Red Cedar, or other suitable softwood. The large, planar hull sides are constructed from ¼” marine plywood. This gives the Neo the look and feel of a production boat with rounded surfaces employed where they matter most, the in-the-water hull shapes and the rounded, wave shedding surfaces of the decks. The easily fabricated hull sides of plywood have smooth, softly flared runs, bow to stern.

In the cockpit, the inner edges of the hull decks are notched back at deck level to provide a nice leg angle when seated on one of the center facing cockpit lounges on each hull. These seats are removable for transport and have backs that fold down for a more compact storage unit in the hulls.

There is also a fully rotating, contour shaped skippers chair located just forward of the aft beam. This chair gives the skipper a full, 360 degree view by just spinning around with his feet. Want to face forward awhile and talk to the other folks on the boat while comfortably driving… you can turn the seat any way you want it while having your fanny cradled in comfort. The owner/builder can even install a contour shaped seat with a reclining back feature. The guy doing the driving gets to pick how he wants to sit and in what direction he will face.

The hull decks have nicely spaced access hatches and ports for easy storage of everything from the camping gear, to a built-in cooler.

The main deck is a hard, flat surface that serves as perfect platform for tent pitching when at anchor. Along with the area provided by the notched deck surfaces, the owner can comfortably pitch a 7′x7′ domed camping tent for remarkable comfort for a family of three. I’ve seen this size of tent available for under $100, making for a great value… if you pick one that can hold together for several seasons.

If the owner so chooses, they can also drop 4′ stanchions into built-in sockets at the four corners of the deck/hull area and hang a large awning over the entire bridgedeck, supported by a topping lift, or boom gallows. Weather covers of this type can be anything from bone simple to pretty darn luxurious, complete with no-see-um netting, depending on the desires of the owner. The advantage is that the tent volume can be extended out over the decks of the boat on each side, making for a much bigger space than a 7×7′ tent. Like anything else about boats, the final choice will be determined by preferences… and budget.

Admittedly, this whole, tent camping thing on an open deck catamaran is not for everyone. For those individuals/families who do not care for this approach, the Neo would probably not be a viable boat for your needs unless you are looking for a big, quick, day sailing beach cat.

If you don’t like camping, I would suggest the build of my Gato Especial design at 21′ LOA. The Gato has a full cabin with interior room for a queen-sized bed, a small galley and a compact space for a port-potti that can be screened for privacy.

The deck surfaces of the Neo are hinged, accordion fashion and folded to a vertical position for the sliding together of the hulls for trailering. As an alternate thought, the solid floor could be eliminated from the design in favor of a dual trampoline surface. The tramp would be built with a simple aluminum tubular frame that also hinges on each hull and folds into place for sailing. Just like the solid floor, it would also be folded up and out of the way for the sliding beam process. It would provide a lot less side windage while being trailered, but also allow for spray and wave action to reach the bridgedeck while sailing. No free lunch with design choices.

The cockpit notches in the main hull also provide strong creature comfort for long sailing sessions, as the crew can bend their legs while sitting on the removable, fold-down seats on each hull. This feature immediately takes the boat away from the typical, tiring beach cat arrangement of having your legs straight-out on the trampoline surface for hours on end.

The tramp forward is made from any of several suitable trampoline products which have small wind and wave resistance, while still providing a nice place to lay out on a warm sailing day. For reference, as well as a highly regarded supplier, you can check-out the various types of trampoline surfaces that are available.http://www.multihullnets.com/product/product.htm

web11wlg

You can go with the typical, beach cat style trampolines made from a mesh-like woven cloth, but

I’ve seen very good knotted, or woven net tramps as well as surfaces made of flat

openuklg openoklg

webbing, sewn at each cross-over point for totally secure footing. Cost, use and durability will guide you to the proper decision on the tramp surfaces

Lunada Design

Creative Boats for Home Builders

Category Archives: Multihulls

Back Bay Sit On Top Kayak

A Modular System Approach to SOT Kayak Sailing, Paddling and Mirage Drive Propulsion

THE BACK BAY SOT KAYAK

DOUBLOON SAILING SOT

Chris Ostlind

Lunada Design
Chris@Wedgesail.com

NAGARE 21′ AND 17′ MIRAGE DRIVE SPEEDSTERS

Making use of Mirage Drive propulsion with more efficient hulls designs

NAGARE 21 DOUBLE
SPEED AND STABILITY FOR DOUBLE RECREATIONAL BOATERS

NAGARE 21 SOT OPTION

ROUGH WATER USE

NAGARE 17 SINGLE
A NEW STYLE OF SOLO BOAT FOR TROLLING FISHERMEN

AFT FACING TROLLING

CHRIS OSTLIND
LUNADA DESIGN
CHRIS@WEDGESAIL.COM

Largo… An SUV for the Water

Collage

Montage

CHRIS OSTLIND

FRESH TAKE ON THE SOLO16 S

A safe, speedy solo cruising craft for adventurous souls

Neo 21 Sliding Beam Catamaran

Modern design, enhanced stability and creature comforts, along with remarkable utility make for a stunning trailerable beach camp cruiser for passionate multihullers.

A Modular System Approach to SOT Kayak Sailing, Paddling and Mirage Drive Propulsion

THE BACK BAY SOT KAYAK

DOUBLOON SAILING SOT

Chris Ostlind

Lunada Design Chris@Wedgesail.com

Making use of Mirage Drive propulsion with more efficient hulls designs

NAGARE 21 DOUBLE SPEED AND STABILITY FOR DOUBLE RECREATIONAL BOATERS

NAGARE 21 SOT OPTION

ROUGH WATER USE

NAGARE 17 SINGLE A NEW STYLE OF SOLO BOAT FOR TROLLING FISHERMEN

AFT FACING TROLLING

CHRIS OSTLIND LUNADA DESIGN CHRIS@WEDGESAIL.COM

CHRIS OSTLIND

A safe, speedy solo cruising craft for adventurous souls

Modern design, enhanced stability and creature comforts, along with remarkable utility make for a stunning trailerable beach camp cruiser for passionate multihullers.

Lunada Design
Chris@Wedgesail.com

NAGARE 21 DOUBLE
SPEED AND STABILITY FOR DOUBLE RECREATIONAL BOATERS

NAGARE 17 SINGLE
A NEW STYLE OF SOLO BOAT FOR TROLLING FISHERMEN

CHRIS OSTLIND
LUNADA DESIGN
CHRIS@WEDGESAIL.COM