I came up with some extra options and want help on a quality as well. The rules deal very well with land based activities, but there is a lot happening on water as well in the books.
These are Extended Specialties
Athletics Specialty: Education (Knowledge)
Characters can use bonus dice from Education to aid in their actions aboard ship, whether steering, taking in or letting out sails, weighing anchor etc. Climbing the rigging and keeping balance on the rolling deck are Athletics (Climb) and Agility (Balance) as normal.
Survival Specialty: Education (Knowledge)
This combination is for navigating by the stars and placement of the sun while away from common landmarks on land.
This is the new Quality and I don't know if it's balanced or not. It might be too weak.
Sea Legs Ability
Add +1D when testing for balance onboard a ship, including when figuring Routine Success. Also, the character is immune to Sea Sickness.
Also, speaking of sea sickness and nausea, any ideas on how to treat that environmental concern?