Possible Clues:

• Sailor’s stability
• Balance on board
• Swell accommodation!
• The Navy's firmest supporters
• Sailor's requirement for supports under the ocean?
• But they won't help you walk on water!
• Ability to maintain one's balance on a ship
• Resistance to seasickness, say, among swimmers
• What a good sailor has
• In the main one finds them strangely ageless