Looks potentially good to me. Crew management could be a big strength, with a campaign based around varying "Admiralty Orders" giving destinations & missions to keep things fresh - pirate hunting in the Caribbean would present different challenges & require different crew attributes to rounding the horn in the middle of winter or blockading a French port. Things can get tense if running short of water (or letting in too much water) & thus keep gameplay interesting even on a relatively uneventful voyage. Maybe introduce some challenges relating to navigation - not an exact science in that era - tied to your masters ability.
Keep on going please!