Outriggers for kayak

[wtarzia]

This is quite a conversion. I had somehow missed the fact, earlier, that you were basically using the kayak as the keel :-)

I agree about that backrest -- makes a big difference in comfort, important for all-day sails or even any cruise over a couple of hours. I am experimenting with my single outrigger to try it as trimaran (a hasty conversion right now with inflatable 16 foot amas) partly based on how comfortable the "trimaran tack" has been on the single outrigger -- sitting in the hull facing forward -- and how wet and inconvenient the "proa tack" was (sitting too high on the side-seat nearer to the ama, more motion/bouncing at that higher rotational arc, garden hosed when dashing through a wave, failure to see a wave coming that will break over the ama ... etc). Perhaps these are not big issues for karger single-outriggers, such as 25 foot proas, but on smaller craft, the discomfort ratio seems to increase by magnitudes (Thus for me in this 16 foot proa hull, the disadvantage is somewhat less visibility into sail performance, less often checking into the mizzen sail whose mast I am leaning against). -- Wade

[JimD]

This is quite a conversion. I had somehow missed the fact, earlier, that you were basically using the kayak as the keel :-)

-- Wade

When I started I wasn't intending on turning it into such a different boat but then it just seemed to make sense once I realized I was going to have to take the deck off and make the amas long enough to require scarfing plywood, so it has sort of mushroomed into more of a full fledged tri. Got any recent pics of yours?

[wtarzia]

When I started I wasn't intending on turning it into such a different boat but then it just seemed to make sense once I realized I was going to have to take the deck off and make the amas long enough to require scarfing plywood, so it has sort of mushroomed into more of a full fledged tri. Got any recent pics of yours?

--- Makes sense to me. The photos on my website wtarzia.com (click on outrigger) represent the canoe as it still is right now. I received this week my two 16 foot inflatable amas for the Everglades Challenge trimaran conversion (Watertribe.com com sells them, their largest one; but they are made by Jack's Plastic Welding Inc, a whitewater raft company), and I just came in from a test inflation outside. I have been planing an edge radius into the new akas today as well. I was hoping for a lake test sail tomorrow with un-finished akas but I don't know, I have too many exams to correct and students getting antsy for them....

I am worried that I should have laminated my akas with some curve so that the amas would both just touch the water, but I was uncertain about how the boat would sit with an expedition load in the center compartment (which will be about 60 pounds I guess to cover the potential full week I will be cruising-racing). Right now the deep, full front of the amas will be about 2 inches off the water I estimate, maybe a little less under expedition load. But the amas swoop up toward the aft and become narrower (like a Gary Dierking foam-and-glass ama), so the aft of the amas will be about 6 inches over the water, creating a boat that may flop a bit from tack to tack. I won't know any of this until a test-float the boat and sit in it with a bunch of my cast-iron weights in it. -- Wade

[Woxbox]

Wade -- I wouldn't worry about a couple of inches clearance, and having the amas too high is always better than having them too low. And don't forget to post pictures of the upgraded boat!

[Dan St Gean]

Wade,

The Hawaiians dealt (and deal) with the ama height pretty easily--elevate the aka with a spacer and relash the vaka. You can tune your height pretty easily that way.

Dan

[wtarzia]

Wox: I agree, simply for reducing drag, and also, sometimes, the windward ama might be pushed up by waves in the steep chop I am often in (exactly what I don't want), so a little clearance is not too bad. I was thinking more about sleeping in the cockpit during the EC race, and be being kept awake by the boat flopping from ama to ama at anchor. But as my first experience with a trimaran, no doubt I will learn much. Actually, I was in someone else's a double-outrigger for a day in the 2009 EC, a kind of Phillipine paraw (long bamboos for each ama), and this boat dragged both amas, which really slowed it in the light wind of day one. We ditched at the end of the day because of a hull leak through a fitting, so I didn't see how it worked in a better wind.

Dan, if I had been smart enough I would have planned the amas to be if anything too low, then I could space them up as you say. I was thinking about the extra windage of spacers, but perhaps this would have been minimal. -- Wade

[wtarzia]

I just upated my website a little. I added a couple of new photos (the two at bottom) and some expanded commentary on this little outrigger. When I have tried out the trimaran-conversion with the Watertribe "TRC-16 foot large amas", I will update again. http://www.wtarzia.com/outrigger.html -- Wade

[JimD]

Wade, that's quite a slew of sail options. I haven't decided what sails to use on mine yet and I'm also tempted to stitch up a junk sail, maybe about 80Sq ft.

[wtarzia]

Wade, that's quite a slew of sail options. I haven't decided what sails to use on mine yet and I'm also tempted to stitch up a junk sail, maybe about 80Sq ft.

--- Yes, the canoe was designed to be a test-bed, and it has well lived up to that goal. I started serious sailing so late in life that I was in a frenzy to experience it all, especially after a life-threatening illness. Maybe I should have gotten to know one mode very well instead of different modes a little well, but, we must pick our poison. :-) I've enjoyed it, anyway.

As for the junk rig, Gary Dierking recently tested it on his outrigger, and he loves it. Go see his comments on his Outrigger Blog (at Blogspot.com). -- Wade

[JimD]

As for the junk rig, Gary Dierking recently tested it on his outrigger, and he loves it. Go see his comments on his Outrigger Blog (at Blogspot.com). -- Wade

I'd cut off the Gurney flap because I just couldn't see it being a benefit on a fast easily driven hull. Maybe the high lift/high drag device would be of benefit to a slower heavier hull. In any case I did max out at 10.2 knots of boat speed in a 10-15 knot wind.

I even reefed on the way home just to see if it is as easy as advertised, and it is. I eased the sheet, went forward and lowered the sail down two battens and it was done. The upper sections of the sail are cut flatter than the lower sections, so you are all set for whatever the wind gods throw at you.

[huisjen]

Damn you all. This has made me waste a lot of time.



Dan

[wtarzia]

Interesting. Perhaps a tad fat for a trimaran, but people have added outriggers to essentially monohull boats and enjoyed them --the Sea Pearl being one, and I have seen photos of a couple of Banks-type dories with outriggers. The commercial glass "Virus proa " (unfortunate name) also had a skinny dory hull that could just barely survive as a monohull (they had a video of someone rowing it without outriggers, but they were rowing delicately, seemed to me). I suppose the Weta Trimaran seems a little fat but it demonstrably goes very fast (is this a scale factor? The Weta is ~16 feet long -- maybe a very light central hull changes the equations). -- Wade

[Dan St Gean]

Damn you all. This has made me waste a lot of time.



Dan

Like wade says, it's a bit chubby. Can you lengthen the whole shooting match and keep it slimmer for the same displacement? I'd also lengthen the amas to keep the diagonal trip likelyhood down some. I like the concept! Keep wasting time! (and strive for 10:1 hull length to beam)

Dan

[huisjen]

Wade, I was thinking of staying pretty light, but also cheap and an easy build. Maybe 1/4" lumberyard ply. A little light framing on 2' centers. One goal is sleeping space below deck. I'm taking a little bit of a cue from Paradox et al., the Solo 16, and a few others. I'm trying to keep the bottom narrow, but in bringing the flare back to about plumb on the transom, I had to bring the bottom out a few inches wider than the original thought of 2'. I don't want to add another panel and complicate things, even though I could lose some wetted surface that way. It's 15' 6", and the sides and bottom can be done from 16' of material. The grid is 1' with dots on the 6" marks. I don't think it could stay upright for long without the amas, but it might with just one.

I had been working on a design that had a good V bottom and some ballast, but decided to consider a multi-hull. It means no centerboard trunk in the cabin, more speed, and more stability, but also nixes my chances of tying up rather than mooring out.

Dan

[huisjen]

Hmm. Narrow the transom by 4", bring the max bottom width down below 24", use the same frames for the amas but shift them to 27" o.c....

Dan

[Chris Ostlind]

While there may be considerations in the design, such as trailering, shallow water use, convertability to a paddled craft, etc... in general, it's always better to go deeper with the vaka hull draft in order to get the main hull as slender as is practicable (10-1 L/B is a good number to observe, if possible) There are other design considerations, but this one is a powerful starting point. From a multihull designers point of view, I'd really like to see those amas longer, skinnier, with a higher prismatic and biased forward to resist pitchpoling exercises in following winds and seas. There's just nothing quite like a ride up and over one's rig to understand the process intimately.

You can still tie-up, if your ama buoyancy is decently greater than your expected body weight placed thereupon. I'd like to see 125% buoyancy amas minimum, anyway, for a boat of this type, so walking, or scuttling over the tramp to the dock should be no problemo. If the boat were being sailed, regularly, from out on the tramp, then you could get by with lower buoyancy amas and call it a sport boat.

[huisjen]

The problem with tying up is that the town regs. say 16' max length (I'm okay) and 6' max beam (not good).

Dan

[wtarzia]

As for sleeping space, all you need is 24 inches for your shoulders, and less if you sleep on your side :-). You should be decently exhausted after a day of sailing a small boat, so falling to sleep should be no problem. You could expand living space outward if you consider some side-decks (not adding to hull width) as many trimarans do. Then you have both speed and sleep, and perhaps a reading-head-room bimini over you. Also have a look at Chris Ostlind's small tris -- I think you can sleep in some or one of them , yes Chris?

But I know well the fantasy of hAving a small fast outrigger that you can sleep in. Almost all of our small-boat fantasies are variations on a theme like this. We engage the noble task of breaking the Formula of the Cosmos (that formula combines ease of build, cost effective, storability, trailerability, reefability, capsizerecoveryability, speed, beauty, and at least week-ending at anchor). We feel that there is a sweet spot in all those variables that will provide that fantasy boat. When somebody gets close, we ooh and awww (as at the recent SCAMP design coup, and our perrenial small-boat favorites, such as Coquina and etc.). Carry on! I still think that boat must be out there, and if not, then in this reduced age, we are dreadfully in need of quests! -- Wade

[Woxbox]

It shouldn't be hard to build amas that slide in to bring the beam down to the docking maximum. Jim Brown's Jaganda shows a very simple solution.

[huisjen]

Folding or sliding in from 14' to under 6' might be theoretically possible, but would require more complex engineering than I'm going to think about right now.

Otherwise, here's a vaka with a narrower bottom and a completely new ama design.



Amas are 15' long. I started with a 12" wide top and 8" wide bottom, put a 15° taper on the ends, and rounded the transition to a 10' radius. Then I brought the forefoot up 6" in a 3' taper, and the stern up 6" in a 4' taper, all with almost no rocker amidships. They're mounted slightly ahead of center relative to the Vaka, and they have more underwater taper aft, which biases them forward a little more. I figure they have roughly 1200# buoyancy each.

One of my design goals is to have an enclosed, mosquito and rain tight cabin to sleep in, so none of this side deck rack stuff, and when I want to go to bed I don't want to have to completely reconfigure the boat, so no boom tent or backpackers' dome.

I did have the thought this morning that I could have the sides of the cabin top fold out as side decks, conditions permitting.

Not exactly looking at kayaks anymore, are we? Not really Sorry about the thread drift.

Dan

[wtarzia]

I show a few photos of my trimaran conversion (inflatable amas) driveway mock-up at www.wtarzia.com, click on "trimaran conversion." Hope to try a float test if not sailing this weekend. -- Wade

[wtarzia]

One of my design goals is to have an enclosed, mosquito and rain tight cabin to sleep in, so none of this side deck rack stuff, and when I want to go to bed I don't want to have to completely reconfigure the boat, so no boom tent or backpackers' dome....

--- In that case, the narrow proa hull (modified to a tacking trimaran and with a cockpit) of John Harris's Mbuli (go to the Chesapeake Light Craft site) is not a bad place to start thinking. -- Wade

[huisjen]

What's the horizontal spar at the water line?



Dan

[wtarzia]

What's the horizontal spar at the water line?

--- That's where I will mount my carbon-titanium hydrofoils! :-) No, as the text explained, I propped it there as a rough waterline reference for the ama-to-waterline relationship. The hull sinks 8-9 inches under daysailing load (just me, safety gear, canteen, and peanutbutter sandwich). That is roughly where the spar is propped under the bottom leeboard bearing and capture-rail. Under 60 pound expedition load, it will sink some more. I will bring it to the lake this weekend and load some cast iron weights on and get inside to check further, then decide if I need to make spacers to bring the amas down a little. -- Wade

[JimD]

Thomas Firth Jones Night Heron:

[JimD]

and a completely new ama design.

Those amas look way too narrow.

[JimD]

Not exactly looking at kayaks anymore, are we? Not really Sorry about the thread drift.

Dan

No problemo. I'm not exactly going to end up with a kayak anyway. So this is more of a minimal solo tri thread.

[Dan St Gean]

Folding or sliding in from 14' to under 6' might be theoretically possible, but would require more complex engineering than I'm going to think about right now.

Otherwise, here's a vaka with a narrower bottom and a completely new ama design.



Amas are 15' long. I started with a 12" wide top and 8" wide bottom, put a 15° taper on the ends, and rounded the transition to a 10' radius. Then I brought the forefoot up 6" in a 3' taper, and the stern up 6" in a 4' taper, all with almost no rocker amidships. They're mounted slightly ahead of center relative to the Vaka, and they have more underwater taper aft, which biases them forward a little more. I figure they have roughly 1200# buoyancy each.

One of my design goals is to have an enclosed, mosquito and rain tight cabin to sleep in, so none of this side deck rack stuff, and when I want to go to bed I don't want to have to completely reconfigure the boat, so no boom tent or backpackers' dome.

I did have the thought this morning that I could have the sides of the cabin top fold out as side decks, conditions permitting.

Dan

I am liking the changes although the vaka hulls will limit it's speed--but that may not be a big deal. I didn't see that you were working with the assumption of great speed here, so I can see where you're going with this.

Is the 16'x6' requirement for tying up at the dingy dock? How about a narrow bottom with less flare, a step out to give nice width for sleeping and seating and an integrated dodger. If you are looking for tri stability in 6' width, you'll have to fold in some manner. The Seaclipper 20 system is one of several systems you could use. Another is the L7 system. Keep it up!

Dan

[huisjen]

...I'd really like to see those amas longer, skinnier, with a higher prismatic and biased forward to resist pitchpoling ...

Those amas look way too narrow.

Can't win....

Is the 16'x6' requirement for tying up at the dingy dock?

Yes.

Dan

[JimD]

Can't win....

Dan

Not around here, anyway. I think you were closer the first time. Not that I have any experience whatsoever designing amas. But looking at the doryish amas of other designers such as the Jones Night Heron I posted, they do seem to be narrow at the bottom, quite flared and wider at the top. Aint sayin nuttin, mind you , just sayin.

[Woxbox]

The single biggest problem with making small trimarans is getting the boat light enough so that it actually floats on the desired waterline. What is the design displacement in the latest iteration? The skinny vaka looks good, but will it float as it's supposed to?

[huisjen]

Damn. I don't know! This thing doesn't have a displacement design goal, per se. The goals are speed, comfort, security, a sheltered bunk and bucket, simple and cheap to build, capable of being moved some distance under muscle power, some ability to handle a south wind against an ebb tide chop on Penobscot Bay, and it should look cool. The ability to carry a pair of Mk 46 torpedos slung under the akas is optional.

Ama design water line is irrelevant, because the only time it will be at that line is when it's not sailing. Heel will submerge it more. I did some rough estimates, and I think the amas will support 1200 pounds each, fully submerged. That seems like enough.

She's got a vaka cross sectional area of 1.68 amidships, 15'ish at the waterline, and if you throw in a prismatic coefficient of .4 (pulled directly out of my ass), that gives a vaka displacement of about 620 pounds. (Maybe someone can refine that for me with a quick eyeball estimate of the hull shape.) Another inch of immersion gives something like another 200 pounds. Figure half the displacement can be boat weight. Here's the current iteration:



If I use three sheets of quarter inch for each ama, and six sheets of 3/8" inch for the vaka, adding back the weight lost in cut waste in the form of rigging, framing, etc, that gets pretty close to 300 to 350 pounds. (Maybe I should only use the 3/8" on the bottom.)

Dan

[wtarzia]

I would be a little worried that the rather fat dory hull might float high enough to pound/slap. Sharpies and dories -- to some extent -- avoid that when heeling over. But a narrower flat-bottom hull might sink enough to keep more of the slappy surfaces under water more of the time. So I wonder if the pounding/slapping is more of a concern on a multihull that stands up more than a mono.

I had a flat bottom ama on my old proa that drove me nuts slapping (and drove me to the deep-V ama, which is nice). My sharpie hull on my current outrigger sinks 8-9 inches udner daysailing load and does not bother me. Our tolerance for noise varies (I have a low tolerance and am the guy who asks his neighbors to turn down their boom boxes), but maybe it is a variable worth thinking about.

Most of the tris I see have rounded hulls, or narrow deep sharpie hulls, and sometimes multi-chined. Trying to think of people you can ask who have experience in your type of tri-hull. The fellow sometimes on this forum, who calls himself Peter from Australia, built a~15 foot Gloucester Gull type rowing dory and added an outrigger for sailing. If you can find him, ask him about pounding, perhaps? He also as a website that detailed his 4 day sailing cruise in this boat. -- Wade

[Dan St Gean]

Good point Wade. Having a bit of draft might be a good thing there. Keeping the stern out of the waterat your desired load is the key to getting some performance. Let's start from first principles.

1. 16'x6' folded beam designed to handle you and camping supplies.
2. Folded beam needs to keep the amas immersed to keep it upright at the dingy dock.
3. Dory form seems to be a natural as does either a transom OR double ender.
4. You want a boat that you can have a minimal camper without the hassle of setting up a tent.
5. Sailing performance goals?

As an outsider looking in, but with some tri and cat experience, I think you should look at the Seaclipper 20 folding setup or the L7 as both ideas keep the amas upright and immersed. You can easily use 4mm for the sides and 6mm for the decks and bottom to keep things light. If you look at some of the tri designs to emulate, they tend to have a flare well above the waterline to give better volume without sacrificing the lower length/width ration that seems to make most tris and cats work. 10:1 seems to be the widest that works well save for light daysailors that have flatter runs. I love your design brief, but think you may need another tweak if you are going to get multihull speeds. OTOH, you may not need the multi speeds and could go with a shorter Sea Pearl Tri shape?

Dan

[JimD]

If you could see your way to vee bottom all the hulls you could come up with something close to the Norman Cross 18, a proven design:

[Woxbox]

As long as you keep working the numbers carefully, you should wind up with a boat that performs at least tolerably well. You can go as wide as 8:1 on the vaka and still get the boat to move nicely enough. (Jim Brown's ratio, not mine.) And your .4 prismatic coefficient seems low. You want displacement pulled to the ends in these hulls to reduce pitching and float the boat properly, which is a shape that brings the coefficient to a higher value. I think the real trick will be building it as lightly as you hope to. What you're designing, by the way, is actually a stretched 3-meter tri. If I remember right, the first one had a dory hull, but as a development class, there are lots of variations.

[Dan St Gean]

As long as you keep working the numbers carefully, you should wind up with a boat that performs at least tolerably well. ... snip...I think the real trick will be building it as lightly as you hope to. What you're designing, by the way, is actually a stretched 3-meter tri. If I remember right, the first one had a dory hull, but as a development class, there are lots of variations.

Or a short Seaclipper 20. Have you checked out the W17? Some good ideas there. Similarly, Gary Dierking's Wa'apa is another boat to look at--it's a double ender, but it's 16'.

Dan

[Woxbox]

Dan - I hadn't seen the W17. That's a good one to study to see some realistic numbers:

Basic DESIGN DATA:
Displacement at DWL: 780 lbs
Buoyancy of Ama: 700 lbs
Estimated weight: ±180kg (400 lbs)
Estimated construction time: 3-400 hrs
Estimated cost of materials: $1900–$3900
depending on source and quality

So 780 less 400 pounds leaves 380 pounds for the skipper and all his gear. Not unreasonable for most skippers. I suppose you could sleep on that boat, but I don't know about sleeping in it. Definitely working at the lower end of what is reasonable in a trimaran. The 3-meters are plenty cute, but they do suffer from lots of weight on a short waterline.

[Dan St Gean]

Another interesting one to look at are Richard Woods' Strike series trimarans--he has a 16' boat to look as as well as a 14 & 18. LOTS of multi experience there.

Dan

[wtarzia]

First test-cruise today of my double-outrigger conversion using Watertribe 16 foot large inflatable amas. Not too bad even if I roughed the whole set-up out late and got in only a short cruise. The amas are too high in day-sailing mode and probably will be even with expedition gear aboard. I must space them down. Aft aka catches water and is a speed brake over 6 knots, rooster tails at 7 knots -- must fix that! This is filmed in video #2. Winds fluky but some gusts gave a good speed test -- amas hold their shape well even under-inflated (on purpose for this test). Two horribly filmed videos at Youtube, the first one is at http://www.youtube.com/watch?v=Yykvfx36XH0 -- Wade

[JimD]

Looks promising, Wade. Isn't it getting cold in Connecticut? Air temps around freezing on the west coast.

[wtarzia]

Looks promising, Wade. Isn't it getting cold in Connecticut? Air temps around freezing on the west coast.

--- It was cool yesterday, for sure, and I shook ice out of the tarp. Next time I will have to wear the drysuit. I am more concerned about ice on the launch ramp. I could slide the former version down snow and ice to the water to avoid endangering the car, and have sailed into December as long as the people plowed the snow at the parking lot -- but not with the inflatables -- I know they are tough but I can't wrap my mind around stuff filled with air, yet. --Wade

[Dan St Gean]

Wade,

Looking good. I watched the first video of the inflatable ama sail. I didn't see what your were taling about with the ama/aka dragging/shooting spray. When yhou talk about spaking them down, do you mean limiting heel by getting the ama down closer to the water's surface? You can also do that by going with a block on the outboard end of the ama and leaving the rest alone. On my ulua, I did a bent lamination to keep the aka up and the ama from dragging, but you could glue on a block and see if that'll do enough to keep it from dragging. Either way, you look like the setup is getting close.

Dan

[wtarzia]

Dan, I filmed the aft aka dragging in the second video. I noticed when the boat heeled pretty steeply on a beat and something suddenly dragged the boat to lee and I heeled even more. I let go the main sheet to let the mizzen bring me up -- that is where you will see the mainsail flogging. I had caught the aka drag at the corner of my eye, and on the next tack I purposely focused the camera on it.

Yeah, I can space the amas down easily enough, though I ought to fair the spacers into the akas to reduce any drag. The fore aka rode high enough to stay out of the water when driven hard since the ama swells to greatest volume (12" dia.) there. The ama reduces to ~ 8" dia. at the aft aka lash-on point and can be pressed down more easily.

Still, this was just a lake with some gusts. I need to get it out on the coast in some rough water for the next test. I was dreaming of going for my 114 sq. ft. lug and shifting the mizzen mast back to fit the boom for the big lug, and shifting to my 20 sf marconi-mizzen, but the amas are not so big as to make up for the fact that the half-beam is only 5 feet in the end! I need Randy Smyth's scissoring 18 foot beam :-) --Wade

[JimD]

I am torn. Not sure if I should continue with the kayak as vaka for my new amas or if I should build an entirely new three panel flat bottom vaka. The main issue is hull form, prismatic coefficient? The kayak is a relatively low volume Greenland style vee bottom with a fine entry and exit. It really slices through the water nicely. This also means it lacks buoyancy at the ends. I can make the hull as deep as needed to support the extra weight of amas and sail rig but nevertheless, sailing proa hulls just are not shaped this way for presumably good reasons. Any thoughts?

[keyhavenpotterer]

This video shows neat solutions to canoe outriggers. Both a sailing canoe with outriggers and a lightweight canoe/tri are shown on the Sound of Jura.



I think these lightweight tri's are fantastic and would make great boats for the US endurance TX200 etc.

[JimD]

Keyhavenpotterer, that video exudes fun and is just about exactly what I am after. My amas will be approximately on par with the ones in the vid but a converted kayak hull would be nothing like the dory canoe hull. Hence my cunnundrum.

[wtarzia]

Jim, I am not quite sure what you mean about your kayak hull. Proas get pretty thin. There's a photo of one off the links page at the Yahoo proa group, and the proa looks to be about a foot wide (though, yes, it is plenty long, probably 25 feet). But if you sail this proa-kayak conversion solo, I am not sure what big problems you forsee. Proas often have 15:1 hull ratios and sometimes higher. And people sail kayaks converted to tris all the time without even raising the topsides as you have done. Haven't you you already gone quite far on this conversion? Irrevocably altered the hull?

Sure, a purpose-built hull has great advantages, though. If you are near done with the kayak, why not sail that while you build a purpose hull? Your amas should switch right over to the new hull. -- Wade

[JimD]

Jim, I am not quite sure what you mean about your kayak hull. Proas get pretty thin. There's a photo of one off the links page at the Yahoo proa group, and the proa looks to be about a foot wide (though, yes, it is plenty long, probably 25 feet). But if you sail this proa-kayak conversion solo, I am not sure what big problems you forsee. Proas often have 15:1 hull ratios and sometimes higher. And people sail kayaks converted to tris all the time without even raising the topsides as you have done. Haven't you you already gone quite far on this conversion? Irrevocably altered the hull?

Sure, a purpose-built hull has great advantages, though. If you are near done with the kayak, why not sail that while you build a purpose hull? Your amas should switch right over to the new hull. -- Wade

I'm probably worried about nothing very important. A minor case of cold feet.

[wtarzia]

I wonder if you are feeling that common feeling when we redesign an existing boat, which we at first think will save us time? At a certain point in a project, we might feel that we would have been better off making a new hull from the start. If that makes any sense at all, I think it is a lesson that can seldom be taught; we have to live it. If it makes no sense at all, then it is cold feet, and your conversion will be just fine :-) It may be be though that your increased knowledge of and interest in outrigger craft has done something more interesting -- your brain is now re-wired with new perspective. You now have 'outrigger mind' and so the standards by which you judge the project have shifted since you started the project. And that has little to do with your actual boat. Yes, armchair-psychology, but it isn't always wrong :-) -- Wade