During our recent trip to the Philippines, Katya and I saw a lot of people on the waterways and even on the open ocean traveling on traditional stand up paddleboards. This is an ancient form of transportation throughout Southeast Asia. The boards are constructed simply out of a few thick stems of bamboo which are lashed together with heavy duty fishing line to three or four thin bamboo crosspieces placed along the deck. The stems are oriented so that the more narrow ends are lashed together at the front, making the bow slightly more narrow than the stern.
Although most people paddle standing using a long single bladed paddle, I have seen some sit and paddle them like a kayak, using narrow two-bladed paddles. These boards range from about 17 ft long to 20 ft and longer. The smaller ones might be used merely as tenders to transport people and supplies from a beach to fishing boats anchored in deeper water, while the longer ones are used for fishing on the open ocean, and usually equipped with a small raised platform for sitting, a fishing net, small styrofoam cooler, and other fishing gear. I expected them to be lightweight but they are remarkably heavy, which has the advantage of greater stability in waves as well as easier handling in wind and when going in and out of surf.
Bamboo contains starch which makes it especially attractive as a food source for many organisms, including fungi and insects such as borer beetles. Because of this it isn’t especially naturally rot resistant, and needs to be treated by one of various methods prior to use in any construction. One ancient method involved immersing the stems with weights underwater for 3-4 weeks which leaches out the starch. Others include smoking, heating, and painting with slaked lime.