Why not run DVD into an RF modulator, then just coax cable in as many TVs
on Channel 3 or 4 as you want? Boat TV isn't exactly high def, is it?

Boat already has video/audio to existing TV and I have no desire to pull
coax to it. Adding another TV and I'd prefer to avoid using RF channels.
No sense having one TV get a/v and the other get RF only to hear the admiral
complain.