Small Boat Design

Discussions around designing small boats including kayaks and canoes.

Exploring chine shapes

Yesterday I saw a (fibreglass) boat with a hard-chined hull in which
the chines were very "flat", ie. almost parallel to the waterline,
rather than curved up toward bow and stern which seems more common.

In a more conventional chine, when the boat is leaned to turn, the
curve which you see in a plan view is the one which makes the boat
turn away from the side you leaned. The "rocker" on the chine tends
to work the other way and one can imagine that if this were taken to
an extreme, turning would be neutralised, or even occur toward the
lean. I surmised that this boat I saw would be unusually responsive
to leaned turns.

On the other hand, flattening the chines would tend to reduce the deadrise
at the ends of the boat, which I guess would impair tracking.

Does this analysis seem sound ? Is there any software out there (ideally
free, and available for Linux:) which can calculate turning and tracking
performance for a range of hull designs varying the form of the chine
like this ? Obviously varying this parameter will change the distribution
of volume, which has consequences for stability and the actual ease with
which the hull can be leaned, but I know of software which calculates
stability curves - that is a hydrostatic thing and fairly easy. It is
the fluid dynamic problem I am interested in.

Andy

Messages In This Thread

Exploring chine shapes
Re: Exploring chine shapes