This is something that I toyed with in the past, so I may have asked a
similar question in the past.

I want to build a floating dock about 7 feet by 14 feet and locate it beside
a seawall fronting a body of water with a fetch of up to eight miles. It
frequently gets quite rough, which the bulkhead makes worse. I am concerned
with how well it would handle this kind of environment, so I was hoping to
hear from someone who might have done this sort of thing.

One thought is to give the raft a lot of mass by way of water ballast (free
flooding barrels with empty plastic jugs inside), but maybe light weight
would be better.

The objective is to provide a means for my wife to board her rowing shell
(when calm, of course), so thanks for any insight some of you might provide.