Small trimarans under 20'

Richard,

Thanks, obviously the 20 has plenty big amas by any criteria.

Marc

 

A couple of things, the Strike 15 is an inshore day sailing boat, and I call it a "geriatric dinghy". So in some way the outriggers are "training wheels". Certainly I try to keep even the lee one clear of the water. That would be easier with two crew; a 15ft boat with the sail rig as drawn is a handful for one person. Remember the introductory text and videos I showed on the Strike 15 page, see them here again

http://sailingcatamarans.com/index.php/designs/27-trimarans-under-25/223-strike-15-trimaran

I wanted to keep the weight down, you'll have seen a photo of my wife lifting one outrigger with two fingers -it's made from 3mm ply. And she and Cameron can easily lift the main hull, its the same weight as a Laser dinghy. So its a very different boat to the Strike 16 and 18

The other thing, relevant to you, is that the outriggers are still hulls going through the water, so you need to make them as long and narrow as possible to reduce wavemaking resistance.

The Strike 20 is still a day sailing boat, but more like a big Strike 15 than a big Strike 18. So I would expect it to be sailed by more skillful sailors.

My personal test is that my wife enjoys steering and sailing the Strike 18, but will not go on the 15, and she won't want to sail a Strike 20 either

The Strike 20 outrigger actually angle down slightly so it's bow picks up buoyancy and the transom doesn't drag. That helps lift the whole boat. Very big outriggers are used on offshore boats that have to cope with big waves. It was waves that caused the low buoyancy outrigger boats to capsize, the fact that the lee hull would dig in helped dissipate the forces from any wind gusts and was considered a good thing. But too many capsized offshore so no one does low buoyancy offshore outriggers any more

Richard Woods of Woods Designs

www.sailingcatamarans.com

 

I would think that the burying of the ama would be a bad thing because it would create more drag on that side, force the boat to bear away, and be a likely cause of pitchpoling if you are going downwind. You could get away with it more if you had foil assist...

 

Under 20' trimarans

I think that it's a shame that more under 20' tri's don't use foil assist coupled with a square or oversquare configuration. At least for a performance day sailing tri-there is much to be gained. From a performance standpoint it seems many are willing to accept the notion that trimarans are slower than cats of the same length-that simply doesn't have to be true-and it's a bad rap.

 

That's where I'm headed with mine, I'll be pretty much rebuilding everything, then just bolting the 40 lb skin on frame main hull under the crossbeams in the middle. Looking at a beam of 14 or 16 feet(I'm having trouble deciding), and length of 16' on the amas. 15'11 on the main hull. I'll use a Hobie 14 mast and maybe a cut down H16 sail(to make a flat top main with more area). I need to do some design drawings and whatnot first.

 

Interesting choices you are considering. I have an all aluminum Hobie 14 mast and a set of Hobie 16 sails.

I consider the mast to be very heavy. With the wide set stays available on a tri, you may want to consider a less heavy duty mast if it is something you do not already have.

 

Doug I'm not convinced that the performance advantages of an over square Tri are enough in the day to day world of sailing to outweigh the advantages of a simple 75% width.

Certainly you seem to rapidly run into construction and stress limitations that end up putting on excess weight that end up requiring ever more bouyancy which requires more heavy duty beams which requires a heavier centre hull to cope with the stress's. There is perhaps a more happy balance shorter than over square.

Yes foils can help but in most daily day to day sailing, they can also be a hindrance. One has to remember that probably 95% of boats that are built are for recreational sailing and they are rarely if ever raced. Would the cost and construction issues of foils warrant their use in that 95% of boats, probably not.

Doug you seem to want push this issue of over square again and again, most designers who have had boats built or those who have built their own designs seem to be under square, perhaps the time has come for you to put your wallet in action and prove your theories by building a full size over square Tri.

 

========================
Wayne, in terms of putting my wallet and time in action I have spent 4 years and several thousand dollars developing a exact scale test model of a 19.5' trimaran that is 22' wide. I know what the tradeoffs are and there is no question in my mind that square or oversquare will produce a faster tri but not only that the use of lifting foils makes it feasible. If you built such a wide tri as a seahugger it could be dangerous because the RM is so high that it would take 15+ knots of breeze before the main hull flew and the pitch resistance of the boat could be compromised. But putting a lifting foil on the daggerboard, Uptip foils on the amas and a trailing rudder foil solves those problems. In preliminary testing it looks like the design is working very well, especially the two different altitude control systems that will fly the full size boat in a 5 mph breeze. It could give its owner the thrill of foiling in light air with the power to go fast when it gets stronger.Not only that the boat will be dry and comfortable and easy to sail with the crew sitting on the sides of a center cockpit. There will be no need to run to each ama every time the boat tacks or gybes. This boat is designed to be easy to sail off a non-surf beach-like we have thousands of miles of in Florida-it will be as easy to handle on the beach as any 19' cat or easier. The foils are all retractable. I'm convinced that this design or slightly different versions of it can make a major contribution to trimaran design in terms of all round fun and speed compared to the same size cat. While the Fire Arrow full size version will use ama lifting foils, a slightly different version of the boat could just use foil assist on the amas but still use the lifting daggerboard foil that is critical to lite air foiling and the tremendous pitch resistance that this design has.
If all continues to go well I'll build the full size version which has been the intention since this project started.
I designed and built my first two trimarans and two cats in the early 70's and I have worked on refining the trimaran concept since then.
Even though it's early in testing of the model, the major elements of the concept have already been proven to work well from lite air takeoff to the UptiP ama foils that require no adjustment while sailing. The next stages of development are refining the foils to maintain early takeoff and increase speed. The self-righting capability(or lack thereof) will also be tested this year.
There is no trimaran anywhere on this planet that offers what this concept does, particularly for trimarans under 20'-it has tremendous potential which is why I have devoted so much time to the design and building of the test model. I hope to inspire others to give this concept a try- it will work well all the way down to a 12 footer.
I believe in this concept and will continue to do everything I can to tap the potential it offers to revolutionize small,high performance trimaran design.

PS- my concept is not just a square or oversquare tri-it is the foil system that makes such a boat feasible. I don't need to "prove" anything about an oversquare tri-Hydropetere and others already done that.

click-

 

Thanks for your input. I wouldn't dare put on a H16 mast, due to weight. I would prefer to put something like an A class mast on it, but I don't have the money for that. I had a really light steel mast on it (1 inch EMT conduit, way too small, coupled with stays too far forward) and the masthead genoa just bent that right over forward. I would love to have a nice carbon mast on it or something but I can't afford that or find one readily available. The H14 masts are around 100 dollars, but they are only 22 feet. I would prefer more like 30. That's still up in the air though. I suppose I could make one... Never done anything like that though. Have you made one?

 

Doug, we have had pages and pages of hypothesis and talk, culminating in a model Tri that has flown on what looked like a broad reach for just a few seconds in a pretty largely uncontrolled manner. I applaud you for the effort but I'm still not convinced that in the real world day of launching, anchoring, trailering, going into wind, going downwind, carrying your wife and 3 kids and their lunch supplies, and that is what your design will have to do if it was to become successful, that you can honestly butt into every thread dealing with Trimarans on this forum ,saying that your way is the best way.

In my view it's time to do less talking and more building to prove just how good this design is. Perhaps if you got yourself into a regime of only allowing your computer to be switched on for half the time of actual boat building time, you would quickly prove what could or just might not be a great concept. We have now really done the talking bit I'm afraid.

 

You weren't supposed to respond Wayne! Ignore the drift bait and stay the course :/

 

=================
That is just nonsense!

 

Guys, I need help here!

What do you think about the mast situation? Hobie 14 mast is way too heavy? Has anyone made their own lightweight mast? I'm thinking about 25-30 feet tall. How hard is it to make one?

 

In aluminum, it's a piece of cake. Go on ebay and search for "sailboat mast". There are a couple of yards on there that have racks and racks of used masts for auction, and cheap. You may find what you are looking for, if what you are looking for is not very hi tech.

 

What about shipping? I live in Utah.