Proa

Warning Spoilers through Storm Surge. The Proa is a type of sailing craft with a crab claw rig see https://en.wikipedia.org/wiki/Proa  First mentioned in Rising Tides to describe the sailing craft of the Tagranesi, 'Lawrence's People.'  Later in Storm Surge the Laa-Lanti boats are described as having crab claw sails, perhaps Proas.

Wikipedia article: https://en.wikipedia.org/wiki/Proa