Optimizing the performance of Boston Whaler boats
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Postby Grossjas » Sun May 21, 2023 10:31 am

Q1: what propeller should be used on a Yamaha F90 on a 1972 NAUSET 16?

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Re: 1972 NAUSET 16 YAMAHA F90

Postby jimh » Sun May 21, 2023 1:53 pm

Q2: what will be the total boat weight (lbs) with engine, fuel, passengers, and gear during normal operation?

Performance of smaller and lightweight boats will vary rapidly with changes in weight load on the boat, so knowing the weight at which the boat isgoing to be operated at will be important to choosing a suitable propeller. If you are planning to go out with three adults, a 100-lbs dog, a 22-gallon full fuel tank, and a cooler full of ice, the propeller selection will be much different from going out with a single 110-lbs person and practically nothing else aboard.

Q3: what is the gear ratio of the Yamaha F90 engine?

The engine gear ratio has a direct effect on propeller selection. Often engines of the same horsepower are available with different gear cases, with different gear ratios. Knowing the gear ratio of the engine in use is important to propeller selection.

Q4: what is the recommended engine speed range at full-throttle?

An engine manufacturer will usually publish the engine speed range at full-throttle where the engine will be able to best product its rated power output. This is the engine speed range in which the engine should be operated for best performance. Knowing this engine speed range is important for the selection of a suitable propeller.

Q5: do you have any performance data on this boat and engine combination now, and if so, what propeller was used?

Having some actual performance data for the boat and engine under discussion is very useful in optimizing the performance. If there is any performance data, please include it.

Q6: what engine mounting height is going to be used with the Yamaha F70 on the shallow engine splash well of the older 16-foot hull?

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Phil T
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Re: 1972 NAUSET 16 YAMAHA F90

Postby Phil T » Sun May 21, 2023 7:31 pm

Classic 16' owners who have installed a Yamaha F90 have done extensive testing. These are their recommendations.

Note- Engine is mounted 2 holes up, with the top bolt in the 3rd hole counting down from the top.

13-1/3 x 18 Yamaha Talon (Performance)
13 x 19 Yamaha Painted SS
13 x 19 Powertech SCD
13.25 x 17” Stiletto Advantage

Size only applies to the specific make and model of prop listed and is NOT transferrable.
1992 Outrage 17
2019 E-TEC 90
2018 LoadRite 18280096VT
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