The Hawaiian Peʻa is classified as a "Crab Claw" sail. A "crab claw" is defined as a triangular sail with spars along the upper(or leading) edge and a spar along the bottom (or rear) edge of the sail. Crab Claw sails are further classified as a "Fore and Aft sail Rig. Fore and Aft sails are much more efficient in sailing "to windward" than Square Rigger Sails.
Manner in which the ʻie of the sail were sewn together and loops used to secure the sail to the mast and spar. This photo of a Tahitian Sail obtained by Captain Cook during his first visit to Tahiti (Click to see more of Tahitian Sail)
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The Hawaiian Pe'a or La, was made out of lauhala, the leaves of the Hala Tree. Strips of Lauhala were woven into a mat averaging 16 inches wide. These mat panels, called 'ie, were overlapped horizontally then sewn together to create the sail.
.The Hawaiian sail is very effective in sailing across the wind or down wind. It can sail windward at an angle of about 75 degrees off the wind. The round hull of the Hawaiian canoe however allows for significant lee drift. Early explores describe Hawaiians frequently paddling their canoes while under sail, especially when trying to sail to windward. Paddling while under sail allowed the canoe to travel higher to windward and reduced the lee drift significantly. Paddling while under sail makes the paddling much easier. It also can increase the canoe's windward ability making between 45 to 40 degrees off the wind.
For more on Sail dynamics click HERE
Herb Kawainui Kane
Within ten years of the arrival of Westerners in Hawaii, the traditional Hawaiian Sail was largly replaced with Western cloth sails and Western "booms" and "spars"...
Prior to Western contact the Hawaiian Sail had a fixed mast that was set slightly forward of the forward 'iako. The sail was attached directly to the mast. To drop the sail the entire sailing rig had to be lowered. Today a Manahiki Island sail rig has been adopted where there is a stationary mast upon which a spar to which the sail is attached is raised and lowered. This allows the sail to be dropped quickly and without having to take down the entire sailing rig.
Below are the traditional names of the parts of the Hawaiian Sail.