Possible Clues:

• Ability to keep one's balance on a ship
• Ability to balance on board
• Marine mammals circling for example -- sailors want them
• Good thing to find on a boat
• Steadiness on a ship
• Members with ability to survive rough voyages
• Good standing in the Navy?
• Salt facility
• Aquatic mammal with roe -- half-hearted adaptation to marine environment
• Sailor's ability