I live in Newport News Va, boat in Seaford Va, lower chesapeake bay and I get all the channels except for 4. I made my own double bowtie and added in a large copper loop for vhf, joining them with a uhf-vhf combiner bolun splitter.
I added in a 20 db powered amp, of course runs on 120v ac.
Channels all work fine. My antenna is directional but mostly works ok even if boat is pointed not in the direction of the broadcaster. I mounted the antenna behind the flybridge plywood forward facing panel. I did notice at the eastern shore with bow facing east, I did not receive any channels.
I do have a dc powered westmarine circular antenna but was never too impressed with the performance. My homemade antenna works better.