Ummm... that's not how it's supposed to work. What you're doing is dead grounding your system to the hull and dumping current into the hull. This is going to chew any metal you have to rust in no time flat and potentially damage your electrical system & generator if not zap you every time you grab a railing! We just had a ship down for a month because they didn't fix the grounds and it destroyed all the main engine bearings in a 4 story tall engine!
The reason there is no Neutral is because your system is designed to take 120v from L1 and 120v from L2 and provide the 240v that your boat is built to use. If you need 120v for N.American stuff, you need to get transformers involved that will create that Neutral line and/or step it to 60v on each leg to provide 120v.
For reference, the 60v on each leg is how American ships are wired and built, everyone else outside of North America uses 220v systems so they're wired 120-120 with no neutral.
Anything that is designed to run 220v either needs to be 120-120 or 240-N, so those lights that were mentioned are expecting a hot leg of 120-240v and a neutral leg of 0v
I'm an electrician on container ships and any ground is a "Bad Thing" out here.
@Jodi: Please,
PLEASE for the safety of yourself and your vessel, undo this ASAP! You're going to need to get some serious 8kw transformers involved if you want to run 110v stuff on that boat, either that or start tracking down suppliers for 220v stuff.