Ive been recently looking at life jackets and life preservers from a more sporting angle - the difference being that its function is mostly to help you swim to safety.

Ive been watching videos of the collar type preservers - the ones that go around the neck and have a large floatation bladder at the front. Seems to me that these are almost impossible to swim in, except on your back.

Is anyone aware of any lifejacket designs that dont impede your ability to swim he way the collar ones do?

The only one that comes close is the military issue LPU-10/P. I havent had any experience with this type, but it looks like it was designed with a goal of enabling you to to keep your head high and out of the water, while leaving your arms free for swimming. Has anyone had any experience with this type of device?