I roger your last but the actual thread was in regards to kayaks and there are not many kayaks far enough out to accommodate a sub's draft. I'm not saying that it's impossible to occur but it would definitely be rare.

That's what diesel-electrics and sailboats have in common, they operate extremely quietly.

Did you ever do boomers? I have several experiences with both Attack boats and Boomers as OOD on Patrol Boats and as Nav LPO on Corvettes in the Bahamas areas and southward. You gotta love a Port of Call in Port Canaveral, Fl.