T&T: Why do longer boats go faster?

[Thomas Averill]

This whole issue confuses me.  I have seen a simple formula which goes
something like this:  Hull speed is equal to 1.4X square root of the length of
the vessel's waterline. Maybe by chance, it pretty well explains why my CHB34
will only go about 7 knots.  Also, I have been told that the  porpoise nose on
some larger vessels uses this device to increase the waterline length to
increase the hull speed.
Maybe the formula for hull speed is just a rough estimate, but it seems to
ignore the shape of the hull, particularly its beam.

I discussed this at my local lap pool and concluded that disstending my
stomach would probably not reduce my lap times.

Can you explain this issue to me please?

Thanks Tom