The simple fact is that a cantilever ( a keel is a cantilever) is
inherently WEAK .... needing FOUR TIMES the strength to be equal of
any other 'simple beam in flexure' structure. Add a safety factor of
4 for offshore or 'hard usage' and you wind up with a minimum of
needing 16 times the strength ... then add fatigue/endurance, etc.
etc. etc. and you wind up with a very complicated structural
element. A cantilever with smooth transitions at the 'root' of the
cantilever is MUCH stronger simply by 'good structural design
practice'.