16 OCTOBER 2017 • FOGHORN FOGHORNFOCUS: MARINE PROPULSION Technical factors in an engine repower If operators choose to pursue an engine repower, several considerations should be made: Propeller match — If the power outputs are different on the replacement engine, operators may need to modify or change the propeller characteristics to obtain the desired vessel performance. Transmission compatibility — If the operator plans to change the engine but keep the existing transmission, it is paramount to ensure that the transmission is rated to handle the torque and rpm of the new engine. Propeller and driveline shafting — The operator should ensure that the existing shafting is of sufficient torsional yield strength to handle the power and torque of the new engine. This is determined by both the shaft material and the diameter of the shaft. Engine installation — The overall footprint of the engine, as well as potential modifications to the stringers, exhaust, seawater and fuel piping must be carefully considered. When looking for a new engine model, review available in- stallation requirements and engine specifications regarding exhaust back pressure limits, radiated heat, air consump- tion, seawater inlet restriction and fuel inlet restriction. These items are critical and may necessitate additional modifica- tions to ensure proper installation. Engine and transmission controls — If the operator chooses to change or keep the existing engine and transmis- sion controls, compatibility with the new engines must not be overlooked. Serviceability — Once everything else is accounted for, ensure there is sufficient space in the engine compartment to perform maintenance on the new engine. Financial and operational considerations of an engine repower Beyond the upfront capital cost of the project, operators should consider the financial impact of replacing versus rebuilding their engine. These can include changes in maintenance and fuel cost — due to differences in fuel ef- ficiency — as well as in diesel exhaust fluid consumption, if applicable. When evaluating maintenance costs, analyze the different prices of parts, as they can differ greatly between brands. One way to do this is through requesting quotes for the price of regular maintenance parts from multiple engine suppliers. Another aspect to investigate is the possibility of financial grants associated with emissions reduction from state, federal and private sources, such as the Carl Moyer Memorial WORK BOATS. THAT WORK. MAVRIKMARINE.COM | 360.296.4051 Unsurpassed quality and attention to detail. Specializing in aluminum and steel new construction, refit & repair.