So yesterday afternoon I took the new GA-30 up to the boat, unscrewed the cover for the emergency
tiller connection and ran the RG58 cable into the bustle through that. With the antenna connected I tried various locations with the antenna up-side up, up-side down, sideways et al. I placed it so I could sit above it and where it was partially sheltered by equipment
on deck, above. There was nowhere that it was not able to receive a signal, even with me sitting directly above it (I guess I don't have such a magnetic personallity after all).
Considering that in some spots the deck is 1-1/2" thick, this antenna seems to be very sensative and I shall be able to locate it in a convenient spot out of the weather
without difficulty (assuming I can learn to splice RG58 of course).
Thanks to all for suggestions...