Monohull vs. Multihull

[haru]

Sorry, this has been discussed before but it the search function didn't show anything, so...

I have been looking around into this theme, but all I found were about stability and speed. I'm would like to know how the designs compare in general or any other measures.
Specifictly, how to they compare in terms of displacement or weights for the same (total) loading capacity and same engine power or system?
A breakdown of mass and size would be nice.

[Fanie]

The question is what is it you expect from your boat -
and what will you use it for.

[haru]

Well, for example I want to know the likelyhood of which ship design my suv can tow.
Or say I want to order a design with sepcific load capacity and engine power but don't know which to choose.
Or I want to know if it is possible to put it on display on the roof.

[PAR]

Apparently there are some translation issues here, but it appears you're relatively new to this sort of thing.

This being the case, you're best advised to gain some experience with both hull types.

Direct comparisons aren't possible without considerable refinement of your question. Since you lack the experience to do this, getting out on both cats and mono's is the real answer to your needs.

To directly attempt to answer your questions, a 2,000 pound cat tows just the same as a 2,000 pound mono hull. Of course with multi hulls you have a width limit, but there are also designs that "fold" or break down for transport.

If you want to order a design, the first step is contacting a designer or plans house (Glen-L, Clark Craft, etc.) and looking over their offerings.

I have no idea what you mean by a roof display.

A custom design is entirely dependent on your needs and desires. If you don't know what they are, you aren't ready for a custom design.

[TeddyDiver]

Originally Posted by PAR

I have no idea what you mean by a roof display.

Only thing I can think of..

[PAR]

You don't need a boat for that, just something that resembles a boat.

[haru]

Yes, I have no idea.
Hence, I want to get a general base for comparison and increase my understanding.

Originally Posted by TeddyDiver

Only thing I can think of..

Bingo! There are fency people everywhere.

Whats "fency" ???

[Fanie]

Whats "fency" ???

And here I am thinking you know everything there is about boats - no come on Richard

Haru, it seems what you know is dangerous. I think Par gave you some pretty good advice. A boat is like a car on water but very different, accidents are still very real and very different.

Anything is possible, but what I meant was big or small, sailing, comfy, cheap or expensive with the tv, hi fi, PC and indoor BBQ... and recommended skipper at this stage

Well, if you stay long enough you will probably become as fency as the rest of us I guess we all had a chance to feel sorry for someone making a fool of himself

Experience is only cheap if someone else pays...

[haru]

Originally Posted by Fanie

Haru, it seems what you know is dangerous.

And here I tried to be an innocent damsel in distress. I guess I was not sexy enough. :lol:

Anyway, I received nearly all the answers I was looking for somewhere else. Thanks for your time, though.

I guess we all had a chance to feel sorry for someone making a fool of himself

Exploring the depths of knowledge is no a folley but not using it.

[Fanie]

Anyway, I received nearly all the answers I was looking for somewhere else.

I would like to know what the right answer was. Maybe I can get it right the next time round

Originally Posted by Fanie

And here I am thinking you know everything there is about boats - no come on Richard
..

There are no fences on boats, Fanie.

[haru]

The answer to my question hasn't been given, but from what I have read I have come to the following answers regarding comparable differences:

For a slight increase in 'structural mass' a multihull for same load & engine (catamaran/trimaran/pentaran) can have higher efficiency.
Up to 15 kn total drag is mostly smaller than a monohull. Depending on design/arrangement etc. efficiency changes beyond 15 kn. Catamaran is better than trimaran at lower speeds.
Increase in mass or displacement works better for the same design/arrangement for multihulls.

[Leo Lazauskas]

Originally Posted by haru

The answer to my question hasn't been given, but from what I have read I have come to the following answers regarding comparable differences:

For a slight increase in 'structural mass' a multihull for same load & engine (catamaran/trimaran/pentaran) can have higher efficiency.
Up to 15 kn total drag is mostly smaller than a monohull. Depending on design/arrangement etc. efficiency changes beyond 15 kn. Catamaran is better than trimaran at lower speeds.
Increase in mass or displacement works better for the same design/arrangement for multihulls.

I suspect it is much more complicated than that.
What is the mission of the vessel?
What is the cargo density and its dimensions?
Are you transporting people, polystyrene foam or osmium?
Leo.

[guzzis3]

Haru,

It seems to me from your posts your looking for a trailerable power boat ?

If that is the case the multihull will require less power for a given speed up until planing speed probably 15 knots or so. Once you get above that it will depend on the specific design.

Multihulls usually have better stability side to side, but may pitch more front to back.

Because multis are "square" at the shear line they can offer more deck area.

If the boat has a cabin or fitout one hull can be more convenient than the other, but it depends on the specific layout.

For a power boat there will be little difference in weight.

In a seaway the multihull will pound less up to a point, but beyond that point it will pound a lot more.

All generalisations.

The differences are far more important in sailing boats.