Rick wrote in message link.net...
Jim Richardson wrote:


2) The pressure at say, 7 feet depth, is about 1.5 atmospheres,

The pressure at say, 7 feet depth, (in seawater) is about 3 psig. It
would take another 9 feet to reach 1.5 ats.

Seawater pressure increases at around .445 psig per foot.

Rick

I do use a mask and snorkel to work on my prop. I even use it to work
on my keel and I just dive down and hold my breath. Its not a
problem. Sometimes when I dont want to dive down, I use a long
handled edging tool to reach the keel, works for the prop too.