The West Marine will auto inflate and it has a lanyard for manual inflation. For super manual inflation there is also tube to blow air into the vest. If you go overboard, don't wait for the auto-inflate, just pull the lanyard.
**As an aside, we recently did a rough race in fairly heavy weather and got soaked. One of the crew was wearing a vest that auto inflated (not sure of the brand). It didn't go off until he was in the car and on his way home. Scared the hell out of him.
I added a strobe to both vests, something that is absolutely critical at night. I also deployed the vest to see how fast it inflates and how full it gets; I was impressed.