Fat Transoms

Why do most Footy designs have wide transoms? Seems to me that wide transoms increase buoyancy at the stern and help drive the bow underwater when running and reaching. Why am I wrong?

I think that ‘burying the bow’ is more a function of forward displacement (or lack thereof) than a wide transom. This ‘nose-dive’ is a problem in all ‘box’ rules where the box limit causes LOA and LWL to be equal. In rule that allow overhangs, such as 10R and A class, nosediving is not a problem.

I suspect that the wide transom gives a longer effective sailing length. A longer lwl is faster than a shorter one (all other things being equal).