All Catamarans are not created equally

[kach22i]

I'm in the middle of reading this article/statement right now.

If anyone would like to talk about the claims and perspective given in this article, I'd be happy to hear your thoughts. Maybe I'll even ask you a few questions, as the article is very rich in information and may require a second reading.

You do not need to be a professional designer or know any math to read this article, which is a good thing for me.

All Catamarans are not created equally
By Malcolm Tennant, Multihulls Magazine
http://www.catamarans.com/news/2006/...Comparison.asp

Just like a monohull it becomes increasingly difficult to make the vessel plane as it gets larger. This is largely because while the planning area is increasing by the square, the displacement is increasing by the cube.................

All displacement hull power catamarans are in reality “wave piercers”. They all slice through the waves.

......All the above features also militate against bow steering, “wave stuffing” and broaching.

[yipster]

sometimes it feels i can even elaborate on articles like this but than willingly fall speachless, its allready so much thats pioneered. powering sailing hulls may found limits yet sailing power hulls and case designed hulls should be possible. bow buoyency and model testing in the widest sence and than general devellopment play a big role i understand. often wonder how stiff big cats really ride as wavepiercing and/or some swath in the hulls may dampen that. interesting cano stern prop and squating explanation too. Craig Loomes and the Mac Donald nacelle discussed a bit but emphasis i feel is repeatedly given to good extensive design offcourse and i go scared to even think any further. another fine article by Malcolm Tennant one of the leading experts in the growing catamaran market, good read and thanks for posting kach

[Pericles]

For comparison. An older style, split down the length, asymmetric power cat.

http://glen-l.com/designs/hankinson/slotmachine.html

PS

What a delightful article. I say this because it confirms and quantifies all the facts, scoured from the hours that I have spent here at the forum, which just goes to show how grateful we should be to those with the knowledge and kindness to post here. Thank you all.

Pericles

[eastcape]

It is very rare to find experienced, information on power catamarans. A majority of design firms hold their research very close to heart. I applaud Malcolm for his role in the development of displacement hull forms for power catamarans, and for sharing his wealth of knowledge with the world so freely. Through his work over the years, he has introduced and educated so many people about multihulls. I mean, just look at how many people are out cruising the world in his designs. Good work.

[kach22i]

My eyes were bugging out. I'll finish this article soon though. I'm only half way though, I have to increase the size of the font or something.

[yipster]

"I have to increase the size of the font"
now you mention it, thats what i should have done also
( with the bottom right looking glass in the xp window ):

[Pericles]

Press Ctrl & + and it all gets massive. Ctrl & - and down it falls.

You mileage may vary.

Pericles

[kach22i]

The article states that asymetrical cat hulls lean to the inside of a turn, but symetrical cat hulls lean a little to the outside.

I think it is important to know why (not sure I really do), and I'm not sure how to visualize it in action one verses the other.

Ref asymetrical...........
Combat Boat in Buatan - Indonesia:

[Pericles]

Looking at the picture you posted, the boat looks like it was divided down its length and a centre section was added. Thus it behaves like a mono hull which leans into a turn. If the asymmetric hulls were much wider apart the vessel would behave as it it had symmetric hulls and would lean outwards in a turn. That's my guess. The wider the catamaran, the more the loads transfer to the outer hull in a turn and this depresses the outer hull.

Pericles

[JCD]

Originally Posted by kach22i

The article states that asymetrical cat hulls lean to the inside of a turn, but symetrical cat hulls lean a little to the outside.

I think it is important to know why (not sure I really do), and I'm not sure how to visualize it in action one verses the other.

Ref asymetrical...........
Combat Boat in Buatan - Indonesia:

Hello there...

Check this out. Now this is what I call a combat boat. The planform is trimaran. Make sure you read about the number of other service vessels each one will replace. It is replacing a substantial part of the US NAVY and, it will do a better job. Pretty extreme.

http://www.defenseindustrydaily.com/...updated-01343/

J