The small trimaran thread

[Dan St Gean]

The outrigger and proa thread has been one of the most fun threads on WBF for me, but I'm leaning towards building a small trimaran to compliment my bigger catamaran made from Tamanu hulls and a Hobie 18.

There are some great resources out there, but I thought it might be nice to gather information in one place. Lists of designs, pictures, and trip reports would be appreciated.

To kick things off I thought I'd link http://smalltrimarans.com/blog/?p=7767#more-7767 post today of a homebuilt tri the builder is calling the E15 using a laser rig and rudder.



What has spurred your imagination? I can think of a few in this category including the Seaclipper 16 & 20, the W17, the range from Mark Gumprecht, the XCR that finished the EC this year by Chris O, and others.

Dan

[Uncle Duke]

Chris White's "Discovery 20" might be of interest to someone:

[Dan St Gean]

Perfect addition! Shall we add the W17?


Dan

[keyhavenpotterer]

Solway Dory's small trimarans deserve to be much better known. This company make terrific sailing canoes and canoe trimarans.



http://www.solwaydory.co.uk/

[xsboats]

We are currently building a W-17 at Seaworthy Solutions for a client . Mike Waters has several nice features that he has designed for this boat, including a wing mast, a kick-up spade rudder, and some really sexy curved akas as seen in Dan's pic above. There is a video of a recently completed W-17 on Youtube , sailing at speeds in the mid teens on a reefed main alone. Maybe someone who is more computer savvy than I could upload it to this thread, Scott

[keyhavenpotterer]

W-17 video



http://smalltridesign.com/W17/study-profile.html

[keyhavenpotterer]

Mosquito looks amazing and completed this years Everglades.



Blog here http://sailnaway.blogspot.co.uk/

[Dan St Gean]

Chris O's XCR also completed the EC (driven by Ben and his wife) this year including the Nightmare section of the Wilderness Waterway. Used as a canoe, outrigger, and trimaran!





Kellan Hatch's version of XCR

Dan

[Dan St Gean]

Roger Mann's tri was damaged in the UFC attempt, but looked really interesting as well.



Dan

[Dan St Gean]

How about Wade's Short Dragon trimaran conversion?



Dan

[Bobcat]

Great thread: I am really intrigued with small tris

[Dan St Gean]

Seaclipper 20 has some attention here and elsewhere.

[Dan St Gean]

Richard Wood's Strike series

[Dan St Gean]

Frank Smoot's self designed tri

[Dan St Gean]

Cross 18

[jim_cricket]

I always liked Kurt Hughes' designs. I sent off for study plans several years ago for his 16' daysailer.



A lot of his designs are "cylinder molded", in that thin ply is laminated over a mold, then cut out and tortured. Its a little less work than constant camber.



I like the Chris White Discovery, too. While the dory type hulls of some of the designs are easy to build, it seems like it isn't so much more work to build a better shape.
I was always tempted to do a glued lap main hull. Remember the Peter Spronk cats?

Cricket

[Dan St Gean]

Seaclipper 16

[Dan St Gean]

I always liked Kurt Hughes' designs. I sent off for study plans several years ago for his 16' daysailer.



A lot of his designs are "cylinder molded", in that thin ply is laminated over a mold, then cut out and tortured. Its a little less work than constant camber.



I like the Chris White Discovery, too. While the dory type hulls of some of the designs are easy to build, it seems like it isn't so much more work to build a better shape.
I was always tempted to do a glued lap main hull. Remember the Peter Spronk cats?

Cricket

A glued lap trimaran of the right design (spoon bow perhaps? High aspect gaff rig?) would blow some minds.

[Dan St Gean]

Mark Gumprecht's drifter 17

[Dan St Gean]

Farrier Tramp

[Dan St Gean]

Newick's Tremolino

[upchurchmr]

Does anyone know what happened in the UFC? What was the damage. I have found almost nothing about the actual experiences from this year. Any links? I would also like to know about Mosquito - I have the SOS link.

Roger Mann's tri was damaged in the UFC attempt, but looked really interesting as well.



Dan

[keyhavenpotterer]

My appologies for the repeat posting. Here's a french tri from Giles Montaubin which he entered into the WB design competition. His boats have won many of the European Raid events so his designs have great pedigree. Triboulet is 6.8m long, 24 sq m sail and only weighs 380kgs. http://chantiermer.wordpress.com/productions/triboulet/

[upchurchmr]

Reply #23 is a repeat of #14. If you haven't seen Frank Smoots web site it is interesting. www.diy-tris.com

[Tom Wilkinson]

Reply #23 is a repeat of #14. If you haven't seen Frank Smoots web site it is interesting. www.diy-tris.com

It may have been a repeat, but i had no idea it was in duckworks this month. I would love plans for that boat.

http://www.duckworksmagazine.com/12/...oot/index.html

[upchurchmr]

The website has a little more detail than the Duckworks article. So far Frank hasn't offered plans. He has had three iterations of the folding boat - primarily the hull, with some interesting observations.

There is another thread with some interesting discussion http://www.boatdesign.net/forums/mul...ver-41318.html

keyhavenpotterer,

My comment wasn't meant to be a criticism, sorry it sounded wrong.

Marc

[Dan St Gean]

Gary Dierking outriggers as trimarans:
Ulua

Tamanu or Wa'apa

or his new Va'Motu could be rigged that way too.

[Todd Bradshaw]

Tris in the 20' range can be awfully nice boats (especially those where you're not trying to add a full cabin and do it with boom tents or similar shelters). All the extra cockpit and net room can really spoil you. About the only thing that really bugged me about our Farrier was that when at anchor in a chop, three hulls can at times have a pretty nausiating, round and round, up and down rocking motion.

[upchurchmr]

There are a significant group of small trimarans drawn by Marples and Jim Brown, pity I could not find a link to any pictures or illustrations on the designers website. The CC23 by Marples was one that kept my interest for a long time.

[keyhavenpotterer]

Eric Henseval's Sardine Run is 5.5m 300kg, can sleep two internally and the hulls look quite simple to build.





http://hensevalyd-english.jimdo.com/...ine-run-5-50m/

Ed

[DavePont]

Hi everyone, great idea for a thread Dan.
I've been pondering options for leeway prevention beyond daggerboard or leeboard. I'm thinking asymmetric amas and or some low aspect keels on the amas. Anyone have suggestions for asymmetric foil shapes? Could the whole ama be a foil section, or is just half of a symmetric shape be OK? ditto for keels and should they be full ama length or shorter.
I did read that asymmetric foils only offer a tiny advantage over symmetric, something like the equivalent of 3 degrees angle of attack. In that case perhaps ama and optional keel might just as well be symmetric, my understanding is a symmetric foil will start to generate lift as soon as AOA is over 0 degrees, this would happen as soon as any leeway is happening. My boat and more importantly my sailing skills are far from being sharp enough to worry about 3 degrees!
cheers Dave

[DavePont]

The Seaclipper range by John Marples is shown here:

http://www.duckflatwoodenboats.com/m...gallery?KID=52

My interest is at the very small end of the range.

I looked a bit further and found the Constant Camber Tri range (CC23 mentioned earlier)

http://www.duckflatwoodenboats.com/m...gallery?KID=55


Dave P

[Dan St Gean]

Hi everyone, great idea for a thread Dan.
I've been pondering options for leeway prevention beyond daggerboard or leeboard. I'm thinking asymmetric amas and or some low aspect keels on the amas. Anyone have suggestions for asymmetric foil shapes? Could the whole ama be a foil section, or is just half of a symmetric shape be OK? ditto for keels and should they be full ama length or shorter.
I did read that asymmetric foils only offer a tiny advantage over symmetric, something like the equivalent of 3 degrees angle of attack. In that case perhaps ama and optional keel might just as well be symmetric, my understanding is a symmetric foil will start to generate lift as soon as AOA is over 0 degrees, this would happen as soon as any leeway is happening. My boat and more importantly my sailing skills are far from being sharp enough to worry about 3 degrees!
cheers Dave

The Wood's Strike series has a new addition--the Strike 15. It is potentially using a small LAR (low aspect ratio) on the amas to accomplish what you are mentioning. It's being used successfully on Little wing tri's (plans not available sadly).


Dan

[wtarzia]

The Windrider 17 has a low AR keel on the vaka. It goes to windward, but not great, I hear. I think if one is going to have low AR, then you need to balance that with high area. -- Wade

[Dan St Gean]

The Windrider 17 has a low AR keel on the vaka. It goes to windward, but not great, I hear. I think if one is going to have low AR, then you need to balance that with high area. -- Wade

Well, clearly one doesn't use it for racing where every last advantage is necessry to win. however, Warren is a bit of a hot shoe as is Richard Woods--and neither of their LAR keels are really the hull shape like the W17 or the Hobie Wave, Getaway, or H16 for that matter. The 16's try to load up the rudder as much as possible to get decent pointing. In a much different vein and craft style, so does Matt Layden's paradox and similar hulls.


For a cruiser, it's probably an acceptable compromise. Me? I like kick up boards if I can have them.

Dan

[upchurchmr]

Have you ever looked at the "keel". The shape is terrible compared to Naca shaped boards. I only sailed the 16 which has a similar blob and it was one of the most terrible boats I have ever sailed to windward. No shape of any quality, small area. If you don't care about pointing ability you should be perfectly happy with these boats.

The last thing any cruiser should accept is poor pointing ability, after all they go out in whatever weather (including changes) and need to be able to sail. Not like on a daysailor where you can choose to sail or not and if you just reach back and forth across the lake you are still doing just fine.

The Windrider 17 has a low AR keel on the vaka. It goes to windward, but not great, I hear. I think if one is going to have low AR, then you need to balance that with high area. -- Wade

[DavePont]

Hi all,
thanks for the feedback, plenty of good points made. I'm immediately reminded there is no one right answer, its horses for courses. I'm just after fun sailing:

...a daysailor where you can choose to sail or not and if you just reach back and forth across the lake you are still doing just fine

, a small say 16'r, perhaps based on a sit-on-top kayak main hull, somewhere less than 100lbs all up. The Strike 15 is very much what I would like, but DIY, ply, for minimal $-).

I think if one is going to have low AR, then you need to balance that with high area

I'd like to keep ama keels no lower than main hull for the drag up the beach. So to get area I'd have to make them long, but then it won't tack easily? Maybe something twice the length of the Strike 15?

I'm thinking I would install stub spars projecting from the bottom of the amas. Mount some NACA keels to these. If I'm going to the trouble to make a shaped foil I might as well try to find an asymmetrical NACA, because with a tri I can expect to just have the leeward ama + keel immersed. If it sucks I can de-mount and try different keel shapes, or cut them off and go to a real kick-up foil, almost certainly leeboard.

Still to-and-fro re amas, asymm could look wacky, may be tricky to make, what shape? not convinced it will work? But I bet someone out there has tried it...

regards Dave

[coucal]

Ray Kendrick has designed some nice little tris (9'10" up to 32').

http://www.teamscarab.com.au/index.html

Some of the boats are ply/epoxy composite hard chine, some are strip built and some are hard chine foam composite with a ply/epoxy construction option.

They look like fun.

[upchurchmr]

Dave,

The Hobie 14 and 16 are asymmetric shapes that have worked in the real world, they just don't go to weather well - they are good but not great. You need a dagger or centerboard to do best. Dick Newick thought they were good enough for the Tremolino which went into production but he eventually made symmetric hulls. Note that he also had a daggerboard - that is quite an authority.
You can always just add 2-3% camber to the NACA sections to make it asymmetric which gives a well known section with asymmetry. This is not a tiny benefit when applied to aircraft, no one but an aerobatic aircraft uses symmetric foils. Can't speak of exact numbers for boats.
Norm Cross made LARs (low aspect ratio keels) on successful multihulls, but bigger than you are thinking about. As I "remember" he used a NACA section. Someone on the forum probably knows from first hand experience.
A center board is a great convienence. You can mount one off center in the Vaka to avoid grounding issues. The Tornado cat was the fastest production boat around for a long time and used dual centerboards (with a sealing gasket) -the centerboard gives you a good shape (best when down) lets you vary the area, and makes a perfect point to tack around.

In my opinion our lack of sailing skills means you should want the best boat you can design/ build. (Yes I was including myself with poor skills). A poor boat + poor skills (or less than great skills) means you are double penalized. A great sailor can take a less than perfect boat, adjust with his skills, and still have a chance of sailing well.

Good luck with a boat. Personally I keep looking back to the Cross 18, which is older, but could have any go fast equipment you want. It is a good all around boat, able to seat people inside if thats what you like, could seat people on a tramp, could probably take any of the beach cat rigs (cheap), and would be relatively easy to build. The width could be larger if you want more power, the amas could be a more sophisticated if you desire. The only thing I don't really like is the clunky hinge design, but that could be improved with money. A reasonable place to start unless you want a really light weight flier.

Hi everyone, great idea for a thread Dan.
I've been pondering options for leeway prevention beyond daggerboard or leeboard. I'm thinking asymmetric amas and or some low aspect keels on the amas. Anyone have suggestions for asymmetric foil shapes? Could the whole ama be a foil section, or is just half of a symmetric shape be OK? ditto for keels and should they be full ama length or shorter.
I did read that asymmetric foils only offer a tiny advantage over symmetric, something like the equivalent of 3 degrees angle of attack. In that case perhaps ama and optional keel might just as well be symmetric, my understanding is a symmetric foil will start to generate lift as soon as AOA is over 0 degrees, this would happen as soon as any leeway is happening. My boat and more importantly my sailing skills are far from being sharp enough to worry about 3 degrees!
cheers Dave

[upchurchmr]

Kurt Hughes has 12, 16, 19, 20, and 23 small trimarans. http://multihulldesigns.com/daysailer.html
If you want a beach cat like boat the 16 would just fit the bill, If you want something with more cockpit the 19 looks good.

[Dan St Gean]

Good luck with a boat. Personally I keep looking back to the Cross 18, which is older, but could have any go fast equipment you want. It is a good all around boat, able to seat people inside if thats what you like, could seat people on a tramp, could probably take any of the beach cat rigs (cheap), and would be relatively easy to build. The width could be larger if you want more power, the amas could be a more sophisticated if you desire. The only thing I don't really like is the clunky hinge design, but that could be improved with money. A reasonable place to start unless you want a really light weight flier.

There is one for sale in Utah I believe right now....maybe on sailingtexas?

Dan

[Dan St Gean]

As to the LAR keels I posted about, they are literally nothing like the compromised hull shapes of the H16, Wave, Dart, W17, etc. These are essentially NACA foils of huge chord and shallow depth. The sluggish performance upwind of the Windrider and similar shapes is not surprising since they don't even have a LAR to rely on. Performance is relative and most certainly pertinant to local cruising grounds. An F18 cat with it's super deep and high aspect foils will clearly kill the H16 upwind (and on every other point of sail), but they aren't going upwind in shallow waters like you might find on the EC route for example. The Tornado is perhaps an ideal compromise. Lots of years of tuning for best upwind performance and the ability to kick up the centerboards and rudders.

Dan

[Woxbox]

My Searunner 25, like all the Searunners, had asymetrical amas as well as a good sized centerboard. The amas create much lift most of the time, which is to say windward ability with the board up was about zero. The biggest problem is that, generally, the ama is not submerged very deeply so you can't expect it to get a lot of grip. In small tris, I like the idea of dagger boards in the amas. It leaves the main hull wide open and you can make them asymetrical and canted to get some lift, too.

[wtarzia]

Hey, I do not remember seeing a photo of the Matt Layden designed Tridarka Raider here. That is quite a boat, I saw it at the 2011 Everglades Challenge (it finsihed in good time despite snapping a board in two part way through). I have photos but they are not posted any where to link to. -- Wade

[wtarzia]

My Searunner 25, like all the Searunners, had asymetrical amas as well as a good sized centerboard. The amas create much lift most of the time, which is to say windward ability with the board up was about zero. The biggest problem is that, generally, the ama is not submerged very deeply so you can't expect it to get a lot of grip. In small tris, I like the idea of dagger boards in the amas. It leaves the main hull wide open and you can make them asymetrical and canted to get some lift, too.

--- Yes, just as Alan Stewart designed his Mosquito trimaran, which recently sailed 900 miles of the 1200 mile Ultimate Florida Challenge (300 miles saved for a kayak in the rivers). He put his boards in tight-fitting cases in each ama. I would be worried about snapping those things off at high speed, but I guess trunks are OK if you are vigilant ALL the time. (Me, I would probably snap them off :-) Poking around the rocky Connecticut coast, sailing between shore and little rocks and islands close to shore, is great fun, and the leeboard makes a gentle depth sounder). -- Wade

PS -- Was the Searunner 25 large enough to have the center cockpit and double cabins, each end?

[wtarzia]

Have you ever looked at the "keel". The shape is terrible compared to Naca shaped boards. I only sailed the 16 which has a similar blob and it was one of the most terrible boats I have ever sailed to windward. No shape of any quality, small area. If you don't care about pointing ability you should be perfectly happy with these boats.....

--- Yeah, they were built with the possibility of a tourist-resort market (low AR keels do not get ripped off by drunken fools driving the boats onto the beach at high speed), which was one way to make those boats commericially survivable (no small consideration in the days before "small trimaran" was a household word :-) When Jim Brown was designing the fishing/camping platform for the WR17 (which he mocked up a few years ago in plywood and uses from time to time), he was thinking about a way to build in a leeboard, but I do not think it was a high priority since he sails his ancient prototype #1 all the time and always gets home with it. High speed reaching can work. -- Wade

[Dan St Gean]

Hey, I do not remember seeing a photo of the Matt Layden designed Tridarka Raider here. That is quite a boat, I saw it at the 2011 Everglades Challenge (it finsihed in good time despite snapping a board in two part way through). I have photos but they are not posted any where to link to. -- Wade

Google comes through again....





Dan

[upchurchmr]

The Tridarka had such a nice hull platform, it was a pitty it had such a small sail area. Compare this to the recent winner of the UFC - Mosquito. I think it is posted below. With a decent size rig, I would prefer this to the Cross 18.

[wtarzia]

The Tridarka I saw a year ago was owned by another Watertriber, and he had put on a larger rig -- that boat moved! He sold not long later for not much over 3K, and if I had had room to store it at home, or could keep it at a marina, I would have bought it in a second. -- Wade

[Dan St Gean]

I think the watertriber bought it for 4k and then sold it after the race. A pretty good deal IMHO. The bigger rig made lots of sense to me. SOS's new tri Mosquito has a nice big rig and good speed to boot. I wonder how they would have fared head to head with the Tornado. Both have big rigs and good righting moment.

Dan