There are the obvious odd yacht names like "Tits".
However there are other ones that would seem to be innocuous except that in certain places the names have other connotations in common usage.
As an example which gave me momentary pause: http://www.yachtforums.com/forums/37149-post145.html
"an identical sister ship named the "Morning Glory,"
Morning Glory was explained to me by my tailor as "That happy situation in the morning when a gentleman first arises and is incapable of dressing either to the left or to the right".
Any other amusing yacht names that come to mind?