Bridge-deck clearance yet again

[Fanie]

Bridge-deck clearance is a major factor seperating the inshore catamarans from the off-shore catamarans. Anything less than 3' of clearance from the bottom of the deck to the water between the hulls would not be well-suited for off-shore use.

Someone's comments off a thread -

I've now read enough posts / articles /comments to believe one want to make the clearance at least a couple of meters It does seem a bit unrealistic and top heavy though. Besides it won't be much fun climbing down a ladder to get a fish out the water - be a bit like fishing from an empty cargo carrier's deck

Since I'm a novice wrt catamaran's, common sence tells me if most of the weight is kept in the floating hull's a catamaran is less likely to become top heavy ? but it may look less atractive when 'boxy' ? when you lift the cabin some or am I missing something ?

What is the ideal height without pushing your luck on the one end or being rediculous on the other ?

It seems most of the catamaran's with a 1m clearance scores high points. Looking at some really large vessels some of their clearances are very small if you take their size in consideration. It seems only small catamarans that should have a low-ish bridge deck clearance so they won't tend to roll over naturally.

What are the design cryteria around this ?

[masalai]

Allow me to point you in the direction of some information beyond what I read somewhere that 10 to 15% of beam gives an idea of a displacement hull capable of handling open waters.

Ribin Chamberlain (living in Tasmania Australia), Roger Hill, NZ, Crowther Designs, Kanga Birtles, Schionningdesigns.com.au, Malcolm Tennant and many more - google these to start & ask by email?

[Fanie]

If I have to e-mail the boat builders it makes this forum obsolete. Besides, each of them will only tell you what their boat clearences are.

I was hoping someone with experience would offer some comments. For instance if your deck clearance is 700mm do you consider it too low, occadional deck slap, or great it never touches.

[Frosty]

It will always touch . Its a case of touch a lot or touch a little bit. My cats bows must 6 feet and I have had green water over them in small squalls. I think there is no escaping this.

I dont know what my clearance is but I can go under there with the dinghy and the engine still on,--so probably 600/700mm.

Sorry not much help, but you will always get bridge deck slamming.

[Pericles]

http://www.southwindssailing.com/art...206/tribe.html

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http://www.google.co.uk/search?clien...=Google+Search

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