My GPS (Garmin) works fine when inside a kayak with the hatch sealed. I've done this in several, both composite and plastic. Of course, it's hard to read when down there. But these experiences were during times when I was testing boats and recording average and maximum speed.

: I know the GPS has to have a visual of a satellite to lock on. I'm sure if it
: was in the hatch it won't work. I'm thinking that the antenna has to be
: physically touching the casing in order to "become one" with it.
: Once you introduce air space then it doesn't work. So, if you had a molded
: plastic case that exactly fit the GPS it would transmit (in my theory),
: but if there were a gap in there then it would not. That's what I am
: assuming. However it seems to work through glass, so maybe it's a visual
: thing. maybe it will "see through" the plexiglass front???

: Where are the rocket scientists when you need them?

: -Malcolm