45 replies to this topic

[Editor]

Take a look. Any comments?

[Hitchhiker]

I have to say the M32 looks really powered up against the Seacart 30........until you get to the lbs/L ratio then it looks kind of fat. The curse of a single keel compared to 2 extra hulls. Still pretty impressive for a single huller!

[rastus]

makes my little boat look fat and under powered

[Y-Bar]

The F24 M2 looks a bit lame. It hard to compare the tri to the mono.
Why not throw the stats for the Reynolds, Lightspeed and Raider in there too that way you can compare one multi to other multis

[glowmaster]

I think the F24 Mk2 downwind sail area number seems off. Main area = 243 and Spin area= 570 for a downwind total of 813.

I just bought a F24 hull 299 and am currently spin shopping. That is why I happen to know.

ed

[Triceratops]

Seacart30 is just so much fun...before introduced in my life I thought Farr40 was fast but the truth is that a Seacart beats even the mighty TP52 in performance ....and that is with 4 people on board at a fraction of the cost. Also you can sail Seacart at off shore races as it handels so well in all kinds of waves.
you just got to have one. This is not a sales ad just a note from a sailor that tested it and loves it.

Yes but an F31R, C31R1D,also can smoke a TP52 for a fraction of the cost of the Seacart. I have to agree though the Seacart look pretty fun and I would probably trade for one if the price was around 100 boat bucks.

Tri

[schakel]

Take a look. Any comments?

I had a look at multihulls for a long time because they are ideal for island cruising ( I looked for them for cruising the waddenzee lying for the north coast of the Netherlands) The draft makes them ideal because you can cross the shallow sandbanks lying between the islands and the mainland.

But what happens with a dagger board when you hit ground? All described trimarans have dagger boards. It's not so hard to design a twisting sword that turns up when hitting ground. The French build the Outremer and even they have dagger boards, there must be a reason no multihull has a twisting sword. Anyone has an answer for this?

Attached Files

•  outremer_45.jpg   28.36K   13 downloads

[remmie]

But what happens with a dagger board when you hit ground? All described trimarans have dagger boards. It's not so hard to design a twisting sword that turns up when hitting ground. The French build the Outremer and even they have dagger boards, there must be a reason no multihull has a twisting sword. Anyone has an answer for this?

Same thing that happens when you run a mono aground.... you stop. Although they do tend to snap off at the hull.

One technique we used on our F31 was; when we finished the board build, pre-fairing, out with the circular saw and cut about 12 inches of the tip off. Structural filler in between the two bits, stick it back together, a very light 3 inch glass tape bandaid around the cut. Fair it up. When you hit something the tip snaps off, you still have a usable board so you can keep sailing and you're less likely to do case damage. Worked bloody well when we clipped a rock doing about 12-14kts, the bang as the tip hit hull was louder than hitting the rock.

I'd suspect because a swing/twist board doesn't have the support for large loads.

Rgds,

remmie

[peejay]

But what happens with a dagger board when you hit ground? All described trimarans have dagger boards. It's not so hard to design a twisting sword that turns up when hitting ground. The French build the Outremer and even they have dagger boards, there must be a reason no multihull has a twisting sword. Anyone has an answer for this?

All Dragonfly trimarans currently in production have "twisting swords" (centerboards) and not daggerboards. www.dragonfly.dk
On the larger ones, especially the 35, the interior is somewhat compromised by the centerboard case. The Farrier interior designs around a daggerboard case appears to be much less compromised. I also believe a daggerboard solution is a performance oriented choice - although the performance of the Dragonfly 35 (and 920) are still pretty impressive for a cruising tri.

[Riddle of Brasted]

The Melges 32 performs impressively well compared to the Seacart. But man even the idea of sailing this Seacart in a nice breeze gives me goosebumps of joy.
Indeed a comparison with other multihulls would be good, the Lightspeed is mentioned, but what about the VOR 40`s?

I will keep dreaming on!

[Peter Johnstone]

Been there and done that with the skiffs and sprit boats.......Melges 32 looks awesome........

For pure sailing thrills, give me an A-Cat, an Olympic Tornado, a Lightspeed or a Seacart. There is absolutely nothing that compares to getting a great multi dialled in with hull, or main hull, flying.

And if I'm going offshore or cruising, well give me the closest thing......begins with 'G' and ends with 'unboat'

[stanlutz]

Well, I have to be biased also. What about the Telstar 28? Granted it is more for family "Performance Cruising". 14 knots with a 20 hp. Built on Back creek in Annapolis. It is a centerboard not daggerboard design. The designer has been added an extra 8" draft option to help sail performance.

Telstar 28 Trimaran Specifications
LOA 27' 8"
LWL 26' 6"
Beam 18'
Beam - Folded 8' 6"
Displacement 3000 lbs
Sail Area - Main 250 sq ft
Sail Area - Genoa 274 sq ft
Sail Area - Asymmetrical 590 sq ft
Draft - Board Up 1'
Draft - Board Down 4' 3"
J 11'
Berths 4
Mast Height 35' 6"

[BeachbumII]

Yes, the turbulence caused by the rotating centerboard case is major.
I like the idea of a sacrificial daggerboad tip. My old Tremolino 23 (T-gull's non-folding cousin) and current Somersault 26 (both Newick designs) utilzies a "crush block"-- a piece of sacrificial glassed foam in the daggerboard case to absorb the kinetic energy of a grounding. I've bonked rocks at 6 or 7 knots and the foam took it nicely. Taking a spare or two is not a huge problem, and they don't have to be fair or pretty.

Turbulence and the fact that if you make the case tight, the keel wont go in ( or get out after a crash ) because of the seaweed and barnacle growth inside the box. The case is also a PITA to antifoul to prevent the barnacles. Also inside the boat the case takes up a major portion of the already small space the mulltihulls have. Mostly boats are sailed in deep waters and are designed to do so. Those "amphibious" qualities are very rarely in use and it is never wise to cross over a sandbank even if it technically possible.

[Rapscallion]

Throw in a couple of Kurt Hughes tries in there for fun. The D23 fast construction tri for example... Then factor in that it can be built (and has been built for about 3500, not counting the hobie rig) and you have a real headscratcher. I'm amazed these little tris aren't more popular. The KH tri takes about 100 hours to build.


LOA 23' 7"
BOA 18' 6"
weight 850 lbs (average builder)
sail area (hobie 21) 222 square feet (upwind)
spinnaker 322 square feet

You don't have to use a hobie 21 rig... You could go with something similar...

[harryproa]

G'day,

An interesting comparison. To start the ball rolling with numbers for other boats, here they are for the boat I am sailing in next year's solo Transpac, compared to the Seacart.

solo boat seacart
length 50 30
weight 1100 2353
beam 23 21.80
upwind sail 538 667
downwind sail 1505 1496
sa/t up 10.86 22.23
sa/l down 30.40 49.87
weight/sa up 2.04 3.53
weight/sa down 0.73 1.57
b/l 0.47 0.73


Compared to the Seacart, it is similar width and sail area. But it is 2/3rds longer and half the weight. The benefits of the lower weight are obvious, but the extra length is almost as important. Multis have to slow down when they start burying the bow. The longer the boat, the harder they can be pushed. Also, the less pitching and the higher the top speed.

Couple of other differences:
The solo boat has a 50' high wing mast which is unstayed so the centre of gravity is lower and it has less windage than the stayed rig. This is not such an issue in light air, but as the breeze picks up, weight and windage aloft become critical so the solo boats mast telescopes down to 27' high.
The solo boat will cost about $50,000 delivered to USA, ready for the solo Transpac.
I will be cruising it from Hawaii back to Aus with my family after the race so it needs (and has) reasonable accommodation.
The solo boat is a proa, so all the weight of crew and equipment is in the hull which is always to windward. This and the flexible mast means that despite being much lighter, the solo boat can carry full sail for longer.

regards,
rob

[BarePoles]

Check out this cool video of a SeaCart 30 ripping along...

HERE

[aA]

anybody know who imports the exploder23 to the states?

[remmie]

Yes, the turbulence caused by the rotating centerboard case is major.
I like the idea of a sacrificial daggerboad tip. My old Tremolino 23 (T-gull's non-folding cousin) and current Somersault 26 (both Newick designs) utilzies a "crush block"-- a piece of sacrificial glassed foam in the daggerboard case to absorb the kinetic energy of a grounding. I've bonked rocks at 6 or 7 knots and the foam took it nicely. Taking a spare or two is not a huge problem, and they don't have to be fair or pretty.

Crush blocks are great at stopping case damage, the only problem is they can result in a board which is only gonna come out through the bottom which can be a problem if you've hit putty. Also not sure about what dynamics there are involved with the forces on the case once it's gone through the crush block and loads up on an angle, could possibly see the trailing edge coming through the back of the case.

That said the sacrificial tip is only really effective if you tag things, if you hit above the sacrificial bit then you've got all the normal problems of a solid board.

Personally, sacrificial tip and wear a decent pair of polaroids but it tends to be deep water with rocks rather than putty around here... think it's a bit of a situational/personal choice.

[BeachbumII]

Theres also one benefit on the daggerboard: The boat still sails if you lift it up a bit. If you lift the swing board so that it actually has effect on the boats clearance, the sailing balance gets messed up big time and the steering feels like you are wrestling a gorilla.

[BeachbumII]

Check out this cool video of a SeaCart 30 ripping along...

HERE

Wow for the first time mulltihull helmsman, thats pretty crazy stuff. The daggerboard is high and dry. I presume that guy didnt know how thin edge he was sailing on

[MauganNacra20]

The eXploder isn't in production yet according to the designers. They have some more sea trials to complete apparently before they are willing to start building them.

Here's a message from the builder:

Exploder 23 is experimental water craft. Many unexpected technical problems appeared during execution of the project, which resulted in much longer realization time. Finally the boat will be launched on the Bay of Gdańsk waters on7-8th April and middle April will be dedicated to the test on the water. Provided that the test results are satisfactory, at the end of April we plan departure to Carnac in France, where the boat will be presented on EuroCut regatta, and than further tests on the open ocean. Final target of our preparations is to sail from Cadix to San Salvador and compare our result with the results of the biggest multihulls that will try to beat that record this season. If the boat passes that exam safely we plan to sail from Bermuda Islands to Plymouth in July. Both trials across the Atlantic will be taken in two-man crew – Wojciech Kaliski and Adam Skomski.

There is a full set of moulds for serial production of Exploder 23. In principle we could already offer it for sale, however taking into consideration the experimental character of the construction we have decided to take the test first and confirm that all new concepts and technical solutions are a success. Except of that during the production of a prototype we realized that some elements should be re-designed to lower the costs of the serial production. For instance we will be able to make out rigger hulls and cross beams in the autoclave very soon.

Taking all above into consideration the price of the yacht hasn’t been calculated yet. Before we started the project we estimated the price to be € 70-80 thousand. However it is sure now


that the boat will be more expensive. We expect rather the price of € 90-100 thousand and the final price we will confirm having finished the tests on the water – in May or June. Nevertheless we hope to offer you for this amount the most exciting small racing yacht that enables easy transportation, preparation for sailing and launching. The first photos, film and data regarding the tests will be available on our web page at the end of April.

Best regards
Krzysztof Kozerski
www.exploder.info

[encinoman]

Take a look. Any comments?

That link sure is a clever way to get us to click on the home page, eh?

Those charts are cool, but missing some kind of across the board rating, PHRF or Portsmouth or something. Not easy to find, and someone is going to say you can't compare the mono and multi single number ratings... but it gives an idea.

What is missed with the Seacart and Melges for example, where both of the the boats have kind sorta similar sets of numbers, is the righting moment.
Showing ratings would bring to light the speed potential of the multihulls from the increase in stability and sail carrying ability.
i.e. with 2 light boats with similar sail, which has the stability to load em up and really go ? Seacart or M32?

[Occams Razor]

aA - forget the little toy - do your family a favor and go halves with me on a new F32 being built by Melvast marine. Family should love it and it's ocean raceable(not lightspeed fast though).

[HookEm]

anybody know who imports the exploder23 to the states?

No, but sure looks interesting. The weight to sail area is ridiculous. It probably planes in virtually no wind. Better go fast since there is not much room for food and water on the transatlantic trip they say they are designing for. They seem to think it can be righted at sea after a capsize by using the folding amas. Here is the link to the web site: Link

[Rapscallion]

That link sure is a clever way to get us to click on the home page, eh?

Those charts are cool, but missing some kind of across the board rating, PHRF or Portsmouth or something. Not easy to find, and someone is going to say you can't compare the mono and multi single number ratings... but it gives an idea.

What is missed with the Seacart and Melges for example, where both of the the boats have kind sorta similar sets of numbers, is the righting moment.
Showing ratings would bring to light the speed potential of the multihulls from the increase in stability and sail carrying ability.
i.e. with 2 light boats with similar sail, which has the stability to load em up and really go ? Seacart or M32?

Actually you could do one better and crunch the bruce numbers...

[Oxygen Mask]

Yes, the turbulence caused by the rotating centerboard case is major.
I like the idea of a sacrificial daggerboad tip. My old Tremolino 23 (T-gull's non-folding cousin) and current Somersault 26 (both Newick designs) utilzies a "crush block"-- a piece of sacrificial glassed foam in the daggerboard case to absorb the kinetic energy of a grounding. I've bonked rocks at 6 or 7 knots and the foam took it nicely. Taking a spare or two is not a huge problem, and they don't have to be fair or pretty.

Yep, elegant in its simplicity. I made mine from foam and glued a strip of resin-coated ply to the edges that the board rubs against.
A centerboard adds weight, complexity (which is usually more weight) and has that turbulence issue.

Attached Files

•  P8250011.JPG   69.48K   10 downloads
•  crshblck2.JPG   14.13K   9 downloads

[Oxygen Mask]

No, but sure looks interesting. The weight to sail area is ridiculous. It probably planes in virtually no wind. Better go fast since there is not much room for food and water on the transatlantic trip they say they are designing for. They seem to think it can be righted at sea after a capsize by using the folding amas. Here is the link to the web site: Link

Really interesting boat. I wonder if the extreme beam to length ratio will make it a handfull to drive.
The main thing I didn't like about it is no conventional cockpit. You're either on the tramps or inside. Since I would have to use it for more than pure racing, I'd like a more conventional cockpit and the cockpit-companionway convenience. Climbing into (and out of) the hatches on the Tremolino is a pain....

[Speng]

Would've been nice to see the L-7 in there rather than the Exploder (that's a terrible name) since you can actually buy/build one. Firebird and Lightspeed would've been good too.

[MauganNacra20]

Yeah but Mask,

Did you not see those nifty seats on the ama's?

hawt!

[Marcog]

Really interesting boat. I wonder if the extreme beam to length ratio will make it a handfull to drive.
The main thing I didn't like about it is no conventional cockpit. You're either on the tramps or inside. Since I would have to use it for more than pure racing, I'd like a more conventional cockpit and the cockpit-companionway convenience. Climbing into (and out of) the hatches on the Tremolino is a pain....

with such interior I doubt that you can cruise it  9.jpg   38.05K   18 downloads

[aA]

aA - forget the little toy - do your family a favor and go halves with me on a new F32 being built by Melvast marine. Family should love it and it's ocean raceable(not lightspeed fast though).

toy? pfffft.

f boats have very little sex appeal to me, beside aren't we looking at 250k+ for an f32? and is it self righting like the "toy"?

[Occams Razor]

$135k FOB Phillipines

Wife and kid friendly(Farallones followed by the delta.)

but you're right - don't flip it.

[Rapscallion]

Would've been nice to see the L-7 in there rather than the Exploder (that's a terrible name) since you can actually buy/build one. Firebird and Lightspeed would've been good too.

Ya,

The L7 has some great features and speed potential.... And it's cheap (relative to the others)

[wjquigs]

I had a look at multihulls for a long time because they are ideal for island cruising ( I looked for them for cruising the waddenzee lying for the north coast of the Netherlands) The draft makes them ideal because you can cross the shallow sandbanks lying between the islands and the mainland.

But what happens with a dagger board when you hit ground? All described trimarans have dagger boards. It's not so hard to design a twisting sword that turns up when hitting ground. The French build the Outremer and even they have dagger boards, there must be a reason no multihull has a twisting sword. Anyone has an answer for this?

This is what happens:


I will definitely be following Remmie's advice when I rebuild the board. However, there wasn't any serious damage to the boat. I think twisting boards would add too much cost to production boats. Plus it's not supposed to happen.

More on topic, the Seacart looks like it will blow away anything on 1 hull or 3, but can you sleep, cook, and poop inside it?

The Farrier 24 is a fairly old design and all of Farrier's designs are conservative compared to flat-out raceboats. His new F22 and the L7 tri are a bit lighter and more aggressive in SA/beam ratio. You definitely have to divide trimarans into dedicated racers and racer/cruisers, just like monos.

[Heavy Cloud]

I had a look at multihulls for a long time because they are ideal for island cruising ( I looked for them for cruising the waddenzee lying for the north coast of the Netherlands) The draft makes them ideal because you can cross the shallow sandbanks lying between the islands and the mainland.

But what happens with a dagger board when you hit ground? All described trimarans have dagger boards. It's not so hard to design a twisting sword that turns up when hitting ground. The French build the Outremer and even they have dagger boards, there must be a reason no multihull has a twisting sword. Anyone has an answer for this?

Chris White - www.chriswhitedesigns.com , has an interesting answer to the dagger vs. centerboard issue on page 104 of his book - The Cruising Multihulll

"A few years ago, while I was working on the daggerboards for a sharpie monohull design, I had an idea for an automatically retracting daggerboard. I have since incorportated this concept into a large cruising trimaran design, now under construction. Its simplicity makes it an attractive design. The daggerboard is wider than normal and its trunk is angled forward. By carefully shaping the board's leading edge and matching it to the sweep angle of the trunk, the daggerboard will, upon grounding, be forced up into the trunk. This design combines the most desirable features of both the center- and daggerboards: Like the center board, it retracts on impact, but like the daggerboard, there is no open, turbulence-producing slot when the board is down. Nor is there a pivot pin to fail or leak."

See attached image...

Attached Files

•  ChrisWhiteDagger.pdf   75.45K   28 downloads

[Heavy Cloud]

G'day,

An interesting comparison. To start the ball rolling with numbers for other boats, here they are for the boat I am sailing in next year's solo Transpac, compared to the Seacart.

solo boat seacart
length 50 30
weight 1100 2353
beam 23 21.80
upwind sail 538 667
downwind sail 1505 1496
sa/t up 10.86 22.23
sa/l down 30.40 49.87
weight/sa up 2.04 3.53
weight/sa down 0.73 1.57
b/l 0.47 0.73
Compared to the Seacart, it is similar width and sail area. But it is 2/3rds longer and half the weight. The benefits of the lower weight are obvious, but the extra length is almost as important. Multis have to slow down when they start burying the bow. The longer the boat, the harder they can be pushed. Also, the less pitching and the higher the top speed.

Couple of other differences:
The solo boat has a 50' high wing mast which is unstayed so the centre of gravity is lower and it has less windage than the stayed rig. This is not such an issue in light air, but as the breeze picks up, weight and windage aloft become critical so the solo boats mast telescopes down to 27' high.
The solo boat will cost about $50,000 delivered to USA, ready for the solo Transpac.
I will be cruising it from Hawaii back to Aus with my family after the race so it needs (and has) reasonable accommodation.
The solo boat is a proa, so all the weight of crew and equipment is in the hull which is always to windward. This and the flexible mast means that despite being much lighter, the solo boat can carry full sail for longer.

regards,
rob

I believe you will do well... I like the thought behind your design. I would be interested to hear in detail how your race goes... do tell.

[BeachbumII]

More on topic, the Seacart looks like it will blow away anything on 1 hull or 3, but can you sleep, cook, and poop inside it?

Been there, done that and Pg and PL did the round Ireland race with it. So yes you can cook, sleep and poop inside.

[kunenborg]

Really interesting boat. I wonder if the extreme beam to length ratio will make it a handfull to drive.
The main thing I didn't like about it is no conventional cockpit. You're either on the tramps or inside. Since I would have to use it for more than pure racing, I'd like a more conventional cockpit and the cockpit-companionway convenience. Climbing into (and out of) the hatches on the Tremolino is a pain....

A catri 27 (http://www.aegeanmarine.com/) has a little more comfort and a bit less speed off course...
For about the same price

[mononowmulti]

Nothing really importand by according to my calculation the SeaCart 30 weights 2050 lbs not 2353 lbs (punds).

[BeachbumII]

Nothing really importand by according to my calculation the SeaCart 30 weights 2050 lbs not 2353 lbs (punds).

Depends wich weight you are counting. The measurement weight for PG and PL for round Ireland was 1030 kgs, Divide that by 0,453 and you get 2273,7 Lbs
The manufacturers announced weight on the website says 930kg wich equals 2052,9 lbs

[harryproa]

I believe you will do well... I like the thought behind your design. I would be interested to hear in detail how your race goes... do tell.

Ta. PM me and I will add your name to our mailing list. Lee hull starts on June 7. We are using the kss build system, expect the 50'/15m hull to be ready for top coat in 4-5 days. Impressive if it happens. Launch target is October, be cool to follow (lead!) the fleet down to Hobart, then the Brisbane Gladstone before chopping off the ends, and putting it in a container and on a ship. Hope to have a month in SF pre race to take people sailing and check the place out.

regards,

rob
proa@iinet.net.au

[Oxygen Mask]

Yeah but Mask,

Did you not see those nifty seats on the ama's?

hawt!

I thought those were BBQs....

[Oxygen Mask]

The Farrier 24 is a fairly old design and all of Farrier's designs are conservative compared to flat-out raceboats. His new F22 and the L7 tri are a bit lighter and more aggressive in SA/beam ratio.

Have to admit though, love or hate the Fboats, by designing all-around good boats, with good handling, decent accomodations, really decent speed yet conservative enough to be (relatively) safe in the hands of less-than-skilled sailors, (plus folding and durable) - Ian has undoubtedly done more to help multis gain acceptance than anyone short of Hobie.

[Rapscallion]

Have to admit though, love or hate the Fboats, by designing all-around good boats, with good handling, decent accomodations, really decent speed yet conservative enough to be (relatively) safe in the hands of less-than-skilled sailors, (plus folding and durable) - Ian has undoubtedly done more to help multis gain acceptance than anyone short of Hobie.

Did you start building your F22 yet?

[Oxygen Mask]

Did you start building your F22 yet?

Nope, but I painted the foils today and epoxied the internal structure into the main hull of my latest design.
All that's left is to build the rig. Little Yellow Tri is almost ready for trials.

[Heavy Cloud]

Quick look at the Displacement / Length Ratio in order

All these hulls are fast.

(these figures are LOA not LWL)

Seacart 30.... 38.90
Exploder 23.... 39.07
TGull2300.... 40.36
Sprint 750.... 49.28
Melges 32.... 54.14
F24 Mk II.... 56.00
Melges 24.... 57.57