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Trawler Propulsion Designs Wing engine in a 48 foot Selene Trawler. A well-positioned handrail surrounds the engine, making engine room checks in rough weather a little safer.


oday’s trawlers have some innovative ideas for propulsion, but these propulsion concepts started long before the powered commercial fishing trawler was born. In the early days of engine propulsion, owners of sailing vessels wanted to add engines but had no practical below-deck space to install a large machine, so they did the next best thing and added a yawl boat with an engine. This looked very much like an over-powered dinghy hanging on davits while not in use. When the yawl boat was needed to motor into a harbor or dock, it was lowered to propel the sailboat. Some say that the name yawl boat was derived

By Captains Chris and Alyse Caldwell

because it was behind the rudder post. Much like the yawl boat concept, today’s ideas for trawler propulsion are functional and very creative. Remember that pleasure trawlers are designed after the first rugged, yet economical, single-engine fishing trawlers, used for the last century to catch our dinner. These no-nonsense, go-anywhere, all-weather vessels were excellent models for the pleasure trawler of today, whether crossing oceans or just cruising the ICW in comfort. Single or Twin Engine? The age-old question starts with, “Should I buy a singleengine trawler or look for a twin-engine trawler for the safety factor?” Many owners believe that if one engine is good, then two should be better. In reality, the most efficient vessel and engine design is a single-engine installation. Look at the oceangoing container ships and tankers. The engine is mid ship, low in the keel and provides straight forward propulsion. Access is simple and easy with a lot of space around the engine to add accessories and perform owner-preventative maintenance. Since the engine is in the keel, the drive system is protected from impact with logs or sandbars. The propeller is above the bottom line of the keel, giving it and the rudder terrific protection in case of a grounding incident. Have you heard about a right-hand or left-hand propeller or engine rotation? Most engines today have lefthand rotation meaning the propeller also turns left or counterclockwise when going forward. Now quick! Think which direction the propeller turns when in reverse gear. If you guessed that the propeller turns in the opposite of forward then you would be correct. Go to the head of the class! Since for most trawlers today that means right-hand or clockwise rotation, then the boat will walk to the right or starboard when traveling in reverse gear. Keep in mind that propellers are also called screws, so think of screwing something in or out, forward or reverse. A true trawler has a full keel that acts as a guide or track to help keep the boat straight when moving forward. There is nothing to keep the vessel on track in slow reverse (not even the rudder), so the boat will actually walk right to the starboard side when in slow reverse. Pay attention to the wide-body-design trawlers that have much more interior salon space because the designers moved the cabin all the


February 2013


Profile for SOUTHWINDS Magazine