Gary,

After reading this review of the different Epirbs I'm not sure I would trust a McMurdo epirb. They had a problem transmitting when the slot where the antenna comes out gets wet.

Here is the review: http://www.equipped.com/406_beacon_test_toc.htm

McMurdo has an update for thier Epirbs available. You might want to contact them.

Mike Hill
www.stlouiscats.com