There
are plenty of day trips available at a reasonable cost on boats
that take you to 2 or 3 snorkelling sites and provide lunch too.
The Red Sea is not very wide compared to most and so is
generally pretty calm as waves don't have a long distance to
build up over, after a windy day, the swell dies down fairly
quickly again.
Here's a shot from the back of the boat on the way out that I've
always found rather mesmerizing, watching the water surging up
from below as its pushed out by the propeller. The white ladder
thing sticking up is for getting out of the water, it hinges
over and drops into the sea when at anchor.