Snorkeling PFD advice

Can someone please recommend a good PFD for snorkeling and where to get
it?

On a recent snorkeling trip to Grand Cayman, we encountered some pretty
rough waters. Since I had brought my own equipment, I was fine in that
department. But I was using the boat's PFD and I found it really was a
hinderance more than a help. I am a competant but not a strong
swimmer. In those conditions, a PFD gives me the security that I
need. Thanks in advance for your input.

The last time I went snorkeling in Hawaii, the company supplied flotation
belts that are basically a band of flexible foam about 1 inch thick and
maybe 6-8 inches wide, wrapping around your waist. I thought those were the
best flotation devices I have used for snorkeling, because they kept me
afloat but never got in the way and didn't have to be re-inflated
periodically like some of the other vests that I've used. I don't know
where you would get one though, and it would be somewhat bulky to pack.

Mary