Shortest is best. Make sure they stay clear. Stuff that accumulates in the cockpit (we had a problem with dead bugs and leaves) can get down into the hose and clog it up. BTW, the valve is most likely on the thru-hull. Its purpose is to close off the thru-hull if the hose breaks so that you don''t sink! Some people choose to close all the thru-hulls when they leave the boat. In the case of the cockpit thru-hulls you are a little dam*( if you do and dam&* if you don''t. If you close them the cockpit may fill with water (not good), if you don''t a hose could break (unlikely if your maintenance is good) and the boat could sink!