Seajet
...
How about: increased windage; weight concentrated right aft; obstructs rearward vision; looks b----y awful.
+1, on any boat / ship short of a square rigger !
I once saw an Anderson 22 with davits; I'm not a violent person but would cheerfully have gone alongside and given the owner a slap just on the principles of trim & taste, if I hadn't been on a hurry for the tide.