Catamaran Desin

[vpkumar]

Hello,
I am trying to design a catamaran for workboat operations. It is about 40m length. But now the owners want a comparison on the merits of a catamarn compared to a monohull.
Could anyone tell me all the draw backs of a catamaran when compared to a similar monohull.

[Nomad]

I do not like cats for recreation in many cases but they work great as work boats. They have more beam, are more stable and in some cases hold a better payload. Depending on the design and the type of sea sonditions they moy or may not provide a better ride.

[yipster]

vpkumar
as nomad said and says plus using the search button on top can and may give you a welth of info

[Thunderhead19]

I've found them to be faster in rough conditions as well

[Willallison]

As the others have suggested, so long as cats aren't overloaded, they make excellent work boats. I don't mean to sound offensive, but if you aren't sure about what is the best type to go for, then are you really qualified to design a 40m boat?

[CGN]

Willallison I think is no surprise to ask for something like that even if you are designer, being a designer IMO opinion is not only "design" anything that can float there is always some experience to apply to new designs and if such experience is not there why not ask?, there are builders and designers that all their life have build the same or similar type of boats and if you ask them about a cat they will go blank, but if you ask them about what they now then they probably don't even need constructive drawings to build, and they are of the best in what they do.

[yipster]

faster in rough conditions

in rough water F1 offshore racing conditions the mono's are faster again

[Thunderhead19]

You're right, but thats racing. Lets look at some work boats. Take a monohull with a similar work platform, and stability characteristics, etc... the long slender hulls of the catamaran subject the operator and crew to less accelerations from hitting waves while moving fwd, in terms of vertical lifting and slowing the fwd motion and efficiency is greater in some aspects.

[yipster]

got to learn to read, remember what i read, not mix things up or go dislectic, sorry

[terabika]

the around the world record is held by a cat! they surf not waves but weather fronts! though, I think it is rediculous to build a boat to race that costs the equivalent of a 3rd world nations GDP...I dont do pro sport for this reason.....poverty is a distribution problem, not a supply problem. Jesus was correct when he admonished; "...you shall always have the poor with you"

[dannyb]

V.P. Kumar, stop. Put the pencil down, please, and think for a second. A man gets on an airplane and says he's going to be the pilot for the flight, and asks if anyone tell him the difference between this cessna twin and the helipcopter he usually flies. How many people do you think will climb off that plane in that second?

Multihulls and monohulls are about as different. A bad multihull design is not worth thinking about. I've studied multihull pros and cons for years and have so much to learn.

Have you ever sailed in a multihull, by the way?

Regards,

Danny Bishop

[dannyb]

terabika,

Poverty is not primarily a distribution or supply problem. It is a problem of corruption first. Witness aid to Africa held up while customs exact brides, or business gives up investing because of political red tape (baksheesh-bait).
However, getting back to boats:

In "Godforsaken Seas", Lundy writes that the Vendee Globe sailors inspire whole nations of youths to go on to greater things, and that the cost of these record-breaking boats (carried by coporate sponsors anyway) is paid back many times. You just cannot measure it easily, that's all.

If Enza had not been built, what would have been done with those millions of dollars from the apple industry? They would have seeped into our capitalist society by another route.

Regards,

Danny Bishop

[vpkumar]

Thanks a lot for all your valued opinions.

It is truethat I have been designing monohulls for many many years. But I have no experience in designing a cat and that is why the question.

[dannyb]

Here's a thought though: I also feel inexperienced in multihull design, so I have designed something small (18ft), something medium-sized (22ft), and so on. My next step is to actually build the smallest one, test it. Depending on how well that works, I'll build another size. My designs are my baseline and the real performance is the true indicator. By comparing baseline against true performance, I hope to be able to predict how good my largest design will be if I take the plunge and build it.

Regards,

Danny Bishop

[Raggi_Thor]

MARINTEK in Norway tried for years to introduce catamarans as fishing vessels, 30-40 feet for coastal fishing. The pros where better speed and stability and you could take the gear up un i a hole in the middle of the deck. The fishermen didn't buy it because the motion was to quick. You have to calculate accelerations very carefully, look at the waterline area compared to the weights or moments, compare this with mnonohulls that you know.