[Lee Stewart]

Prior to the Japanese attack on Pearl Harbor the fill for most life preservers and flight vests came from the island of Java in the Dutch East Indies, harvested from the pods of the ceiba tree. A cotton-like fiber called kapok also was water resistant and buoyant, but the Japanese captured Java soon after Pearl Harbor, cutting off the supply.

The "Kapok" life preserver vests used by the Navy and Marine corps during WWII, and were in many ways easier to use than the "Mae West" type, as they did not require inflation and were easier to secure. This type of preserver was intended more for "General" use

Tests by the U.S Navy had found 1 pound of milkweed fluff was as warm as wool, but six times as light, and it was six times as buoyant as cork.

A pound of milkweed fluff could keep a 150-pound man afloat for more than 40 hours.