Propeller for 13-footer with Tohatsu 9.8
Posted: Mon Oct 16, 2017 2:05 pm
At present [my classic 13-foot Boston Whaler boat has] a Tohatsu 9.8-HP four-stroke-power-cycle short-shaft engine with a 8.5 x 7.5 propeller. I run a load of three or four adults. [The Tohatsu 9.8) is only [accelerating to] 5,000-RPM at WOT.
I am looking for a bit more RPM and possibly [for the hull to reach] plane. I know this is a lot to ask for a 9.8-HP.
The boat and engine feel like you are in fourth-gear but really should be in third-gear--if you know what I mean.
I put on a foil (to the anti-ventilation plate] hopes of easier planing, but no luck.
I see Tohatsu offers a 8.3 x 6 and a 8.0 x 5 three-blade propellers. I think the 2.5-inch drop in pitch to 5-inch would get me closer to 6,000-RPM at WOT and better [acceleration onto plane from a standing start], and the drop in diameter would keep slip resistance and strain down on the motor, compared to trying a four-blade propeller.
To anyone [with a 13-footer and a Tohatsu 9.8-HP engine and has tried]:
can your offer some feedback?
I am looking for a bit more RPM and possibly [for the hull to reach] plane. I know this is a lot to ask for a 9.8-HP.
The boat and engine feel like you are in fourth-gear but really should be in third-gear--if you know what I mean.
I put on a foil (to the anti-ventilation plate] hopes of easier planing, but no luck.
I see Tohatsu offers a 8.3 x 6 and a 8.0 x 5 three-blade propellers. I think the 2.5-inch drop in pitch to 5-inch would get me closer to 6,000-RPM at WOT and better [acceleration onto plane from a standing start], and the drop in diameter would keep slip resistance and strain down on the motor, compared to trying a four-blade propeller.
To anyone [with a 13-footer and a Tohatsu 9.8-HP engine and has tried]:
- --a 8.3 x 6 three-blade propeller
--a 8.0 x 5 three-blade propeller
--6-pitch proper
can your offer some feedback?