By this time everyone must be getting tired of my discussion of the Willard Horizon's sailing ability or lack thereof. But with the price of diesel quickly approaching $5 a gallon, I was curious about how much help the sails could actually give. Powerboat zealots should relax. I'm not advocating a wholesale return to sailboats. But many trawlers, including Beebe's original Passagemaker and Buhler's current Diesel Ducks, offer the possibility of sail assist. Is it worth it? Let's see. For the last couple of weeks, whenever conditions permit, I've been conducting experiments on motorsailing at various engine powers and wind speeds. In steady winds, with waves less than two feet high, I measured boat speeds over a three mile course in both directions at specific throttle settings on engine alone and with engine and sails. The course was always laid out so that the wind was abeam, the most efficient point of sailing. As point of reference, the fastest speed my Horizon could achieve under sail alone in a 20 KT wind was about 5 KT. I estimated that the drag of the 18" x 14" prop cost about 20% of the power the sails were capable of producing. When motorsailing, the prop drag is negated and the full power of the sails can be used to add to the propulsion of the boat. On one afternoon last week the wind averaged 20 KT. The Perkins 4-107 engine was set at 1700 RPM, generating about 8 HP and produced a boat speed of 5 KT. The speed was measured with a Garmin 48 GPS and confirmed by Loran. On the second run the sails were raised. With the engine still running at 1700 RPM and a 20 KT beam wind, the boat speed was now 6.44 KT. It would require almost 17 HP to move the boat this fast under engine power alone. Thus the sails were adding 9 HP of propulsive force with a 20 KT beam wind. Each 30 sq. ft. of sail was producing 1 HP. This is within 8% of the figure used by racing sailboat designers who estimate 1 HP produced by 27.5 sq. ft. of sail in a 20 KT wind. The Willard sails are hardly racing rags so I'm satisfied. Last Sunday I went out again in a much stronger wind averaging 25KT. The engine speed was set at 1200 RPM, giving a boat speed of 3.5 KT. This takes about 3 HP at the prop. It takes very little power to move a displacement boat at slow speed. Because the wind was so strong, I only raised the 180 sq. ft. jib. With the jib up the boat speed increased to 6.2 KT. This would take about 15 HP under engine power alone. The jib was generating the equivalent of 12 HP, about one HP per 15 sq. ft. Given that a 25KT wind has over 1 1/2 times the energy of a 20 KT wind this seems about right. Also the large Willard jib is a much more efficient sail than the puny mainsail. I haven't worked out the exact fuel savings yet but motorsailer owners should take comfort in the fact that if they can arrange their trips so that strong winds blow from the beam, the aft quarter, or the stern they can markedly reduce their fuel costs. Any other T&T trawler owners whose boats are equipped with auxiliary sails are welcome to chime in, adding their information to the collective data base. Larry Z ************** Get the scoop on last night's hottest shows and the live music scene in your area - Check out TourTracker.com! (http://www.tourtracker.com?NCID=aolmus00050000000112)