(US/UK/International) Can anyone provide details on tax deductions for a US citizen working as a Merchant Mariner aboard a ship whose company is based in the UK?

Background:

I'm in the application process with a gas transport company out of Glasgow, Scotland. In an initial conversation, a HR manager outlined some of the perks of working internationally, and briefly mentioned something about tax exemptions/reductions. Does anyone have experience in this area or guide me into some reading material? As I evaluate my options with other potential employers I'd like to take full advantage of anything I can. My other potential employment is with an extremely stable government company in the US that would provide stronger benefits, but most likely a lower salary than this UK position.

Thanks in advance!