Wooden hull vs steel hull

Discussion in 'Boatbuilding' started by slthegreat, Nov 18, 2014.

1. Joined: Nov 2014
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slthegreatNew Member

Hi guys Im new to this forum but I would definitely need some help here.

Does the material of the hull makes a difference in terms of block coefficient between wooden hull and a steel hull?

And what is the best way to calculate the block coefficient if I do not have the GA of the ship.

2. Joined: Oct 2008
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Location: Japan

Welcome to the forum

The hull material does not or should not influence the Cb at all. It is merely a function of the Length (Lwl), the B (beam) and the D (draft) asa ratio the the volume. It is just a value that helps to provide some perspective to what could be expected from the hull.

Such as a Cb of 0.9 is clearly nearly a brick in shape, thus something like a super tanker. A Cb of say 0.3 is a high speed hull form as it is slender, like a patrol boat or pleasure craft.

The material is a matter of the design and what the design is to satisfy. The full load displacement whether wood, or steel matters not, so long as the boat floats at the design draft. That is the "design" part...does it float as expected?

Having the GA is not essential. You simply need:-
1) Lwl
2)B
3)D
4)displacment/volume

3. Joined: Nov 2003
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PARYacht Designer/Builder

Welcome to the forum.

You should pick up the book "The Nature of Boats" by Dave Geer. It'll cover many of the ratios and some of the calculations you'll want to know, if asking questions such as this. It's an eclectic mix, a good read and makes these often dry and abstract concepts, palatable to the novice, just looking for some understandable information.

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DCockeySenior Member

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