R 22

Rhodes 22

 

Choosing a Propeller

We have a buyer who is irate because we cannot tell him whether he should be getting a 9 X 6 or a 9 X 5 or a 9 X 6 (which is a four-bladed prop) with the 8 hp Merc he has on order. In my day all motors came with the same prop for that size motor and if you were really sophisticated you junked it and asked for a sailboat prop and there were no size choices.

I told him I never touch the dirty things but he still says he is not happy dealing with someone who can't tell him the right prop for a Rhodes but he won't buy a computer and join the List.

Can anyone pick a number?

stan/gbi


After I read all of your posts re which prop to use on a Honda 8, I walked outside to see what I had on Dynamic Equilibrium. It's a standard Honda prop, stamped 240 X 220. My Feb, 1994 Honda BF8A Shop Manual Supplement on p. 2 lists this 3 bladed 240 X 220 mm prop as standard. The same data table gives the English measure equivalent prop as 9 X 8.7 inch. 9 inch diameter is clearly the biggest prop that is possible to fit on this engine. The prop barely clears everything. I like this engine/prop combination.

On smooth water, I can hit an indicated 6.5 knots. It cruises quietly at an indicated 5 knots while getting 10 nm/gal. It idles nicely up to a dock & stops the boat on a dime. Until the prop starts cavitating, it will punch through waves very forcefully. Seems like Honda knew what it was doing with this engine/prop combination.

Roger Pihlaja
S/V Dynamic Equilibrium


I recently took delivery on an 8hp long shaft Honda. The standard prop was 9 x 8 5/8. I asked about a "sailboat" prop and was told, by the dealer, a 10 x 9 was recommended by Honda. I tried to contact Honda Marine directly to confirm but haven't yet received an answer.

Bruce


Run, do not walk, away from that dealer. That is some of the worst advice YTD.

First off the largest prop is 9 ; 10 inches will not fit. Assuming someone reversed the numbers, 9 x 10 is listed for light load in the Honda manual; this would be the worst prop in your case.

Straight from page 18 of the Honda 8 hp manual:

Michigan PJ-169 x 10light load
Michigan PJ-219 x 8medium load
Michigan SMC-399 x7heavy load

The stock is a medium to light load prop, great for a tender or other light small fast boat, I tried it on a Rhodes and the motor never got more than half the throttle. I ran the 9.25 x 7, it did better around the docks and got the power into the water for some nasty head winds (35 knots+); it's down side is cruising speed. The motor runs at high rpm's leading to more noise. The prop I wanted would be around 9.5 x 7.5 but they do not make it.

Remember if you cannot get the motor up to the recommended rpm range you will never get all the horsepower you paid for or might need.

The bottom line, the safe bet is the 9 x 7, but I might try 9 x 8, the risk is about $60 each.

MJM

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