If you're ship offers free wifi access you might be spared GDPR regs since technicaly you not connecting to the net from an EU country, but a maritime connection. If you log on to a mairitime connection via mobile, be careful. They can be costly.
Most ships have internet cafe's set up for HSXers who can't stand to loose large amonts of fake money while getting away from it all. ;-) That might be your best bet. Have a great trip!