Quote:
Originally Posted by meaux fishing
If you under power a boat too much wont you cause the engine to strain more than it should? Seems to me like you will cause your motor to wear out faster by putting just enough to get it on plane...
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In my experience, a 20 ft boat loaded to a total weight of 2000 lbs should have a top speed of about 35 mph with a 90 hp motor, but can be throttled back to 24-25 mph and stay up on plane (rough numbers, depending on hull design, trim tabs, etc.) At 25 mph or so, the motor is not really maxing out the hp, and is operating near the peak in its fuel economy.
It is probably true that a 90 hp motor operated in such a manner will wear out before a 150 or a 225 hp motor operated most of their lives pushing the same boat around under 30 mph, but we all know that the 150 and 225 will burn tons more fuel, and probably spend most of their lives pushing the boat around at closer to 40 mph. The newer 4 cycle japenese motors have not been around long enough to be sure of their life spans operated at 80% of their rated hp rather than 50-60%, but I'm betting that they'll last a looooooong time.
It all depends on how you fish too. My fishing style probably puts < 10 miles on the motor per trip, and even with a boat that can handle light offshorse/nearshore duty, I expect to still average under 20 miles per trip. Those distances probably won't wear out motors operating at 80%.