Hull terminology

[Pablo]

Hi,
I'd like to have a thread that I can refer to describing all the different aspects of RIB hulls.

I've already had excellent descriptions of what is the deadrise, with diagrams might I add. Bow and transom i'm ok with . Please could you, my boating oracle, now be kind enough to shed some light on other terms such as :
- planing pad?
- low sheer?
- any other aspect of hull design?

Here's the diagram for deadrise
http://rib.net/forum/attachment.php?...1&d=1201542558

[codprawn]

A planing pad is basically a flatter section at the stern.

A deep V hull is great in rough conditions but does need a lot of power to drive it so you use a lot of fuel. A flat bottom boat will be much faster but will slam a lot.

A planing pad is going to be a bit of a compromise as it will still give a harder ride than a proper deep V but will be better in calm water as you will use less power for the same speed.

http://en.wikipedia.org/wiki/Rigid-h...nflatable_boat

This article on Wiki has a bit about it.

[9D280]

Originally Posted by Pablo

Hi,
Bow and transom i'm ok with .

...unless it's a Dory, where those two become remarkably similar!!!

[Pablo]

9D280 you're right about the bathtub dorys

OK but is a planing pad the rear of a progressive hull that gradually flattens out or is it the 10cm of complete flatness that I have on my boat but it appears to be absent from, for example, a SeaRider ?

[Pablo]

I found these other terms on http://www.rcboataholic.com/hulls/hullsdef.htm

Beam: The width of the boat at its widest point, typically at the transom for planning hulls.

Bow: Front of the boat.

Chine: The line of intersection of the bottom with the side of a vee or flat bottomed vessel.

Deadrise: Degrees of V-shape hull angle measured at the transom of planing powerboats.

Deck: A deck in a ship corresponds to a floor in a building. It is the plating, planking, or covering above the inner bottom forming a floor.

Freeboard: The vertical distance from the waterline to the top of the deck at side.

Hatch: An opening in a deck through which cargo may be handled, machinery or boilers installed or removed, and access obtained to the decks and holds below. For R/C's this is how we access, servos, fuel and motor.

Keel: The backbone at the very bottom of the hull to which frames are attached.

Ride pad: Ride pads are used to ensure that you get a clean edge to spill water off the ride areas to reduce drag and increase speed. They are an easy way to get a clean sharp edge.

[Nos4r2]

Cookee can you define Speed Rails please?

[9D280]

Is a chine not gererally the join where flat plates change angle?

E.g in sailing dinghies a GP14 has a single chine, Enterprise, Wayfarer have double chines. 420 has none.

[K&S]

Originally Posted by 9D280

Is a chine not gererally the join where flat plates change angle?

E.g in sailing dinghies a GP14 has a single chine, Enterprise, Wayfarer have double chines. 420 has none.

Is a 420 not a Radius Chine ??? Just to help confuse the matter

[K&S]

Are Dorys a combination of reverse radius chine and radius chine???

Now my head really hurts lol....

[jwalker]

Originally Posted by Pablo

...or is it the 10cm of complete flatness that I have on my boat but it appears to be absent from, for example, a SeaRider ?

That one.

It isn't necessarily only at the stern.

[Richard B]

Warped-V

Excellent explanation here: http://books.google.co.uk/books?id=R...um=1&ct=result