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Old 11-06-2006
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Multihull displacement

I am currently looking for a suitable trimaran to do some long distance cruising and to liveaboard. I grew up as a liveaboard in San Diego on a Catalina and a Cheoy Lee. I am avid single handed sailor so I need a manageable boat. I have looked at Newicks (Echo 36 & Val 1), Kelsall (Tango 32), Condors, and a Crowther Twiggy 31. My question is about the importance of trimaran displacement. I know how much multihulls suffer from being overloaded and all of these trimarans have a displacement between 3,000 to 5,000. What does displacement mean for an ocean going trimaran as far as anchoring, carrying capacity, ect. As a monohuller displacement was always drilled into me as being very important but is it the same for tris? Finally, do you have any other suggestions for boats to look at? Thanks in advance!
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Old 11-06-2006
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A better question might be asking what you need on a long distance cruise, and whether any of the boats in question have the capacity to carry all that you consider necessary. You might be better off looking at catamarans, for long-term liveaboard use, as they generally have far more usable room than trimarans of comparable length.

Generally, as a rule, for the same length overall, the catamaran will have the most space, the monohull the second most, and the trimaran will often have the least space. This is due to the very shallow bilge and narrow design of most trimarans. Stowage is generally a problem on most trimarans. This is generally not the case on catamarans, where having too much space and loading it up too heavily is usually the problem.

Personally, I don't like the Newick designs, as they generally have a solid wingdeck or a partially solid wingdeck. While this increases living area, it also makes the trimaran less seaworthy IMHO, as it increases windage, and the wingdeck is also vulnerable to slamming in heavy seas.

Trimarans generally have better sailing characteristics than catamarans, and generally also have less windage. They tend to point higher and tack more easily than catamarans. Part of this is due to their ability to pivot on the main hull, something catamarans can not do.

Pounds-per-inch, PPI, is also another important figure to look at. This is the amount of weight it takes to depress the waterline 1". It is important to note that this number is not a static number, but changes dynamically as the boat is loaded more and more, generally increasing as the waterline rises.

I'm also a bit surprised that the multihulls your looking at are that light. My 28' trimaran is more than 3000 lbs., but it is not a racing trimaran by any means.

The major advantages of a multihull have to do with speed and shallow draft. The catamarans also have the advantage of more living space. What are your reasons for wanting a multihull??

One book I would highly recommend you read, even though it is getting a bit on the old side, is Chris White's The Cruising Multihull. This book is excellent at talking about the pros and cons of using a multihull as a cruising sailboat. It also debunks a lot of the older myths about monohulls being inherently superior. While most monohull sailboats are capable of self-righting, they are also quite capable of sinking. Most boats, including multihulls, are not capable of self-righting. Multhihulls have the advantage of not being as likely to sink, since they do not have several thousand pounds of cast iron or lead trying to bring them to the bottom of the ocean, and most modern multihulls are made of relatively buoyant materials. Yes, they are most stable upside down...but a keelboat monohull is most stable sitting upright on the bottom of the ocean... which would you prefer—an upside down but floating boat, or one that has sunk out of sight.

As for anchoring, multihulls generally require a slightly larger anchor than a monohull of the same length IMHO. They have a lot more windage than a monohull, due to their extreme beam. I carry a 33 lb. next generation anchor as the primary anchor on my boat. I am a firm believer in having good ground tackle, as it is the only thing keeping your boat and home from being destroyed in a storm.

Any specific questions, let me know.
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