To Rudy: Our boat is a 1979 Marine Trader Trawler, 44 ft. It is registered (documented) in Canada. She has a mast of 13 ft and when mounted on the flybridge the top is 27 feet above the water line. The anchor light sits on the top of the mast and projects 360 degrees. The yardarm has two spreader lights which illuminates the aft cabin deck. This arrangement has been certified by Lloyds of London as well with our surveyor and insurance company. The Federal official who approved the documentation commented the boat with this arrangement satisfied the Colregs (inland and international). This may help you determine what may be suitable for your sail assisted trawler. At anchorages we also use kerosene lamp(s) hanging from the yardarms to conserve DC power over longer periods of time. Regards Leonard Stern, INDIFFERENCE.