OK, think about it a little more. These guys are not likely to have
fished until the waves built to 14' or even 6' and 40 miles off
Clearwater the water is deep enough that the waves prob were not
breaking and the survivor said they swamped when they hauled the
anchor. I would guess that it started to get rough, they hauled the
anchor and swamped and then it got really rough.
Why did they swamp? Anchored from the bow in a 21' boat, you'd think
the bow would rise with a wave. When you read about fishing accidents
like this, you sometimes read they anchored by the stern and that when
they hauled the anchor it drops the stern just enough that a wave
comes over and that is all it takes.
The survivor also said they did not put on life jackets until after
they turned over so that also indicates they were not too worried
until then leading me to think it happened suddenly and not completely
as a result of high seas.