Interesting... how do conventional VHF aerials work on a wooden hull?
Surely they need a ground plane? At least around the aerial base.
Otherwise what you have is a length of coax whose screen suddenly ends in nothing, and the inner conductor goes to the base of the aerial. RF stuff was never my strong area (I used to build pirate ratio transmitters in the late 1960s, with a pair of 807s; we even considered powering it from the 700V DC train rail
) but this doesn't seem right. The cable screen needs to go to that ground plane.