I thought I had made all the decisions necessary to order a new prop, but now I've received two different "recommendations" as to pitch
for a 3-blade 18" FlexOFold. I know that another Jonmeri 40 like mine went through 3 different FlexOFolds before finding the correct prop, so I really need to get this right on the first go.
Here is the dilemma: FlexOFold "strongly" recommends 14 pitch
but one of their agents (who has been extremely helpful and savvy) "would recommend 18x13 if you want to achieve the full rating of 3600rpm from the engine
. You could use 18x14 but this is likely to limit the maximum rpm
achieved to around 3000-3200. The advantage of 18x14 though is that you would achieve good cruising speeds at lower rpm
Have you gone through a similar debate in selecting pitch for a FlexOFold? Of have relevant experience in actual use to share (i.e., "followed FoF's recommendation but have never been able to get top revs")?
As full-time liveaboards we have the boat loaded down; cruising through the Philippines
and SE Asia
the last several months we did a LOT of motoring in windless conditions and calm seas. So good performance and fuel
economy at cruising speeds is important. BUT Larry Berlin taught us that if you can't get 3600rpm out of this motor
, you've got the wrong prop. Our Yanmar
4JH2E is old (8750 hours) and has surely lost
some umph, but we've decided to defer a full rebuild
as she really runs well and burns no oil
despite a bit of blue smoke.
Considering our old prop doesn't provide any clues -- for some unexplained reason, a prior owner installed a massively-oversized 22" MaxProp 2-blade. At least we could adjust the pitch, rather than needing to disable the boat and remove/return the blades for a different pitch as will be the case if I make the wrong choice with the FlexOFold.