I think I hear Mars calling...that setup should work fine without electrolysis
problems. The only tricky bit with a steel hull
is not to lose to much signal on the line to the insulated backstay. Minimize the run inside the boat, no sharp corners, and use standoffs on the uninsulated part of the backstay and the steel parts
I had a friend whose NZ 'expert installers' ran his antenna
line up inside an aluminum arch for about 10 feet. He couldn't hear the Mrs, let alone Mars till we reran it outside.