Catamaran VS Trimaran

[Duckhead]

Here are the (very few) things I learned while on our two years of cruising in a Gemini. Trimarans are wetter while pointing...that upwind "Ama" knocks the top off every wave spraying everywhere.
Trimarans have less stability at anchor as it rocks to either the port or starboard Ama as you move around.
PDQ is a great boat, love em, wish I had one but it will never outsail a Gemini. We crewed on a PDQ while racing in the bahamas and got annihlated by an older gemini.
Gemini has a center board(s) not dagger boards.
Neither are they the boat to sail around the world in, they are coastal cruisers.
We never had any concern navigating with one engine, it's really a non-issue as we had no probs but obviously twins would be better at getting around in tight spots. Duckhead

[cat man do]

As an owner of a 1980 Valiant wagon that cost $1200, I say sell the car and get a better boat.

But hey, nice car.

[44'cruisingcat]

Have a look here: http://www.kelsall.com/CatvTri.htm

Ian Farrier, who has designed many tri's and at least one cat states that at over 40 feet a cat makes more sense because the space increase is dramatic. I agree but I would say that it happens closer to 35 feet really.

[Tnflakbait]

My 2 cents. I Strongly believe that performance potential in Catamarans and Trimarans is the same or very similar. Modern Multihull design is in its infancy. It really only started in the 1950's. I have noticed that current designs dictate peoples opinions on the two boats. Modern catamarans are too big inside and far too heavy. Most trimarans now are foldable and small. They are also fast.
Orange 2 is the fastest boat in the world. It is a catamaran. If you want any performance do not go with a PDQ or a Gemini. They are slow. If you want space they are both good. Catamarans with good accomadation under 40' are slow and look bulky. A well proportioned cat in my opinion is the Gunboat 48. Some would say that this is a performance boat but I would disagree. All cats should perform!
There are other good cat designs out there as well. I like the Conser catamarans and believe they are well proportioned. Under 40' Trimarans are great because the middle hull is very livable. On a small cat if the cabin properly proportioned it is a bit small.
However catamarans take advantage of the hulls. Most trimarans do not use Amas for accomadation. The horstman tris along with a few others did.
My 33' 1964 CSK cat is not perfect. However it does have more accomadation than an F 31. It also has topped 20 kts. double digits are EVERY DAY. Some would point out that the hulls are only 2 feet wide. and that the boat weighs 4000 pounds.
I guess what I'm trying to say with all this rambling is that they both can be great boats. And it depends on the design. I think there is a lot to look forward too in multihull design.
Tristan

[FredMG]

A few years back studies on seaworthiness & safety between cats & tris was done. The conclusion was that tris are more prone to wave capsize (under "ultimate" conditions) while cats tended to be more prone to wind capsize. That being said, it worth noting that most cruising designs, either type, generally can take lot of bad weather & sea conditions before ever reaching that critical state nearing a capsize. Trouble is, if it happens, it's well documented that it happens rather suddenly, and not always under conditions you might expect, such as massive storms. Heavier cruising designs however have excellent safety records, and boats such as the Heavenly Twins 26 or 27 cats have circumnavigated, crossed oceans, all with no negative circumstances. Same with most cruising trimaran designs too. Good seamanship is paramount of course, and preparation, plus a little good luck thrown in of course.
Regarding accomodation, I mentioned the Heavenly Twins as the design has huge accomodations for such a small cruising cat. You simply won't find the same level of accomodation in any trimaran near that size. Larger designs can have much more accomodations than same size tris, up to the roughly 37 - 40 foot range, where, depending on the design, some tri's have interiors easily rivaling that of similar sized cats. However, remember that each type has it's interior space arranged according to what's possible. Tris under roughly 40' generally never had space in the outer hulls for real cabins, even smallish ones, and accomodations for daily living by necessity are in the center hull. Cats of any size can usually have good headroom in each hull, with standing headroom in the bridgedeck only in designs starting close to 28 - 30' (the HT 27 being one of the smallest with standing headroom on the bridgedeck cabin). Also, if you intend to dock the boat often, or live aboard at a dock, a cat takes up less beam than a similarly sized tri, which may affect docking fees. Cat's & tris also handle a bit differently, but it's not a major concern and easily learned as you sail each type.

[eugene kalsow]

Hello to All.My name is Eugene Kalsow.I have diesel powerboat[Florida],but just fell in love to cats.I know nothing about them,will go to get courses next 3 weeks.In 6 month I'd like to buy cat about 40-43.Still don't know--what kind is more save...[I have properties in Curacao and thinking to reach it].Thank You.

[Roy M]

Sometimes, it's better to experience the difference yourself, rather than have any significant dependence on the (possibly limited or deduced) knowledge of others. Some ways to gain experience with individual designs is to check with local multihull racing associations, contact multihull brokers, subscribe to Multihull Magazine and contact people therein, go to boatyards and find owners (give them a hand sanding rather than take up their time), or try to catch one while sailing and get a contact from them. Those are the things I did thirty-some years ago to decide which boat I was going to build. Even then, there were plenty of incredible designs that were worth the effort to discover. Browns, Kantolas, Crosses, as well as a bunch of really hot British and Aussie designs. Today there are even more, in more sophisticated construction techniques. Go do the research yourself, or you will kick yourself later.

[sandy daugherty]

Nicely put, Roy. I would addthat it helps to narrow your research to your price range, easily done using Yachtworld.com . A more difficult parameter to define is the quality of construction, which will require you to look at a lot of boats. Try to get a look at the unfinished and hidden parts of the boat to develop a feel for the builder's standards of construction. On an older boat you can expect to see a lot of older equipment, but if it works and doesn't look like a prop from "On the Waterfront" its a sign the boat has been continuously maintained. Use a tough Surveyor.

[Maren]

Originally Posted by sandy daugherty

A more difficult parameter to define is the quality of construction, which will require you to look at a lot of boats. Try to get a look at the unfinished and hidden parts of the boat to develop a feel for the builder's standards of construction. On an older boat you can expect to see a lot of older equipment, but if it works and doesn't look like a prop from "On the Waterfront" its a sign the boat has been continuously maintained. Use a tough Surveyor.

Absolutely.

Good advice for pretty much all cases of a person buying a used boat, too. I would add that its also good to find a surveyor with a lot of experience in that mode of construction too (e.g., metal, wood epoxy, grp)

[dcstrng]

Originally Posted by FredMG

Trouble is, if it happens, it's well documented that it happens rather suddenly, and not always under conditions you might expect, such as massive storms.... Good seamanship is paramount of course, and preparation, plus a little good luck thrown in of course...

Think this is more often than not the general state of affairs, whether multi or mono hull… Was rereading some of Moitessier’s writings recently and was struck by the fact that some of his more exciting knockdowns in Joshua were not in conditions he considered extreme and occurred seemingly with little or no provocation – and if the sea can surprise such a veteran traveler, I suspect any of us are vulnerable… He eventually analyzed the peculiarities of his boat and being the experienced voyager that he was, developed techniques to avoid its vulnerable areas, but from what I read in Chris White’s (and several recounts here in this forum), every boat mono, multi, tri or cat has its idiosyncrasies…

Following this thread, I find it curious that tris were considered more vulnerable to one sort of capsize or the other – wonder if this is the older tris reputed to have smaller floats, or if there is something endemic to the tri design – comparing similar sized bridgedecks etc., etc… from a manufacturing point of view, I’d think cats would rule the day; two hulls to build rather than three and generally more sumptuous appearing accommodations once the performance cat is large enough to accommodate standing headroom in the bridgedeck… Nonetheless, viewed from the perspective of a monohuller who is perfectly comfortable living down in the water, the tri looks more familiar and far less threatening… the fact that many performance oriented cruising tris don’t have multiple queen-sized beds I don’t find a great burden so long as the performance and stability rewards are there…

[Talbot]

I find it curious that tris were considered more vulnerable to one sort of capsize or the other – wonder if this is the older tris reputed to have smaller floats, or if there is something endemic to the tri design

As a cruising catamaran lifts a hull, the grip on the sea from its keel (either long low aspect ratio, or a daggerboard) is reduced, thus the boat tends to slide sideways. The heavier the cat, the more that this happens.

On a tri, as it lifts up, the float digs in and provides the fulcrum for the capsize.


It is worth saying again, that cruising multis (both cat and tri) are less susceptible to a capsize than a mono having its keel fall off. However, a pitchpole due to moving too quickly is something to be wary off.

[dcstrng]

Originally Posted by Talbot

On a tri, as it lifts up, the float digs in and provides the fulcrum for the capsize.

Probably a dumb question, but bear with me… Couldn’t the tri float be designed to have the same (or similar) shape and buoyancy capabilities of a catamaran hull… or is it because the tri floats are generally a slimmer aspect than that of a cat hull… maybe it has to do with the fact that with the tri’s windward hull well out of the water a tri is acting like a narrow cat, or perhaps a proa… just trying to think through this, and wondering if there isn’t a way to design around it…

To a mono-huller, the tri can seem to have several theoretical advantages… the dagger/centerboard/keel can be in the main hull, so always to windward of the float responsible for stability (which could assumably be designed to slip sideways easily with the main hull having sole responsibilty for inhibiting leeway…) Likewise the concentration of mass in a tri should be far from the float as, unlike a cat, there are seldom any living accommodations or major storage weights in the float areas of a medium performance tri…

Oh well, just a curiosity from the peanut gallery -- something I'm not grasping I guess… T’aint trying to say it isn’t so, just wondering why it is…

[Talbot]

This probably gives as good a picture of the forces and pivot as any

YouTube - Trimarans - Lunatic Sailing

[sandy daugherty]

God I love that stuff! But it doesn't happen on cruising cats. And getting the center hull airborne on cruising tri's almost always requires the use of a Yard crane. Having ten people on a boat that know what they are doing is a rare event, and most cruisers like to carry more than a half a tube of toothpaste to go around, so don't get too excited about the prospects of sailing off into the sunset with a sweetie by your side on one of these megamillion dollar gossamer erections.

That said, I see no reason why production cruising trimarans aren't more popular, other than the cost of the extra hull and akas. Wait, one more problem; if they don't fold, you will be moored out almost forever. You might even be denied the end of the pier because you could block too much of the channel into other slips. Bummer. That means everything, groceries, guests, replacement parts, and pets have to be ferried back and forth in an open dinghy. Small point.

I fell in love with the plywood tris of the 60's, and formed firm opinions about everything before I ever sailed a boat. I'm still kind of wistful about thos dreams, aided by the fact that Wharram always drew a few extra female figures in his ads!

For anyone looking, there are some PDQ 32's on the market for under 6 figures (yes, thats still a lot of money) but they a remarkably good sailing boats, build by master craftsmen in the Whitby tradition. I owned one, and the only thing my 36 offers over the 32 is more waterline, and easier transit from the helm to the bow.

Yes, a well prepared Gemini (in the hands of one of the few Gemini masters) is faster than a PDQ. But not otherwise.

So what are you going to do NOW if you don't have the wherewithall to snag a $90,000 boat loan? Buy older, buy smaller, buy smarter; maintain and improve to yacht standards (i.e. nothing from home depot) and move up when you can. Don't do anything on your boat a hard- nosed surveyor wouldn't approve of, or your potential future market will be limited to the rare dreamer-with-money. But in the meantime, stop dreaming and start sailing. Just do it.

[henryv]

Yes, a well prepared Gemini (in the hands of one of the few Gemini masters) is faster than a PDQ. But not otherwise.

Not my experience - a local sailor with a 105 has tried to catch me many times - so far no contest - PDQ's are probably more weight sensitive so perhaps the fact that I sail lightly loaded helps.