The explanation is perfectly possible. It is a well known problem and can happen anywhere - it can also be extremely local and only effect certain boats at certain pontoons in a marina for example.
Thought I'd add to this post and say hello to a a fellow RIB Owner in Alaska. I'm in Anchorage and own an Almar, 19' RIB. Usually fish/boat in Prince William Sound or out of Seward.
John
