To the best of my knowledge, military flotation systems are not designed to help you swim. Swimming requires the output of energy that you need to retain in a survival situation. The PFD provides flotation so that you can keep your head in the air while not expending energy you may need to survive hours or days in the water. Once you inflate a PFD the farthest you should swim is to your liferaft or the helo hoist the Coast Guard drops.
That LPU-10/P looks rather clumsy. I don't see how that design would aid in swimming. You'd still need to deflate the bladders and with them under your arms, they'd seem to interfere with your stroke much more than the collar type PFD's.
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Better is the Enemy of Good Enough.
Okay, what’s your point??