This is my buoyancy aid of choice for Olympic Nacra 17 sailing. Its ergonomic fit works with well on both warm and cold days on top of a rash guard or many wetsuit layers. Its neoprene construction allows stretching around your personal shape while maintaining a snug fit. Side zipper and clip makes it easy to put on and take off. Its huge front pocket holds nearly anything you could want on the water! I’ve carried several full size spanners while racing without a problem.
The sides extend downward enough to cover the sides of a harness. There is a harness loop on the front to hook over your trapeze ring to help keep the vest down, but I find this isn’t necessary and personally don’t use it. With the correct fit the vest easily stays down over my torso. Also, with its sleek exterior design I no longer have to wear a pinnie or rashguard to prevent snagging!
As an added bonus the neoprene can absorb and hold water which is quite useful on windy days. Sail normally during light wind minimizing water immersion and then when the breeze picks up just dunk yourself or the vest for an added weight bonus. I wear a size M.