Several thoughts:
If this is a hobby - find another hobby. When one’s hobby takes precedence over the Lord’s Day it goes against the commandment “Thou shalt not have false gods before me” (the hobby being the false god, as you value your time focusing on it instead of our Lord).
If this is a career, then thank God you have been blessed to make a living at something you love to do which makes it feel more like a hobby than a job, but all the more reason to make sure to honor the Lord’s day in thanksgiving and praise for blessing you so.
Relevant Radio and EWTN offer Mass via radio, television and internet connections. If you don’t already have the equipment, invest in whatever will pick up one or more of those signals (with satelite radio these days I hear there’s almost no excuse anymore). Then be sure to block out whatever time on Sunday Mass will be aired and spend that hour worshipping via soundwaves. You will receive communion in spirit and you will be honoring the commandment.
When it comes to getting to Mass while out to sea ‘hard’ or ‘difficult’ in that it’s a pain to alter your schedule or route in order to accommodate a mass just keep in mind the path Christ took on your behalf to keep His appointment at Golgatha. It was cumbersome, heavy, painful, he fell three times and still He honored his obligation to His Father for you. Whatever inconvenience you have to go through to honor your obligation to Him will never be anything close to what He went through for you.
If it truly is absolutely unavoidable for you to attend Mass or tune into a broadcast, then on your immediately next opportunity go find a church, go to confession, and if at all possible attend daily mass the next morning before setting out to sea again. You are truly blessed to have something you enjoy doing, to have a wonderful fiance and to be kept safe while at sea. Please, please, make the time to thank God for all He’s given you by keeping His day holy.