400 with 1.76 transmission prop choices

[SONIC]

Kent can you jump on plane with full ballast and 6-8 people in the boat?

[larry_arizona]

Had 4 people in boat, 575# lead, 100% bow, 60/60% rear pulling a wakeboarder at 22 on plane, no problem.


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[HFarr]

"cup" also adds surface area to the blade. Makes it a bit longer so to speak.

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[Hayden]

Running at 10.8-11 mph I am only pushing about 3150-3200 rpm with the ACME 3591 (16x13.9), I haven't used another prop but based on what I've seen this is great. I pushed to 11.5 or so last time I was out and it was maybe up around 3400 or so.

How much ballast/passengers are you carry for those numbers?

[larry_arizona]

I get similar RPM’s 100/100/100, 575# lead full fuel and 2 crew, 1 rider in an SA


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[Holdmybeer]

I get similar RPM’s 100/100/100, 575# lead full fuel and 2 crew, 1 rider in an SA


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So all in you are around 10k on the water getting 3200 rpm....I would say perfect

[KnoxMojo]

"cup" also adds surface area to the blade. Makes it a bit longer so to speak.

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Are you sure about that? The way Eric at OJ explained it to me is that more cup actually makes the blade react as if it were shorter while keeping the same surface area. Like a dog ear standing straight up or folded over. I asked about a new prop they had with more cup (950 and 951) and he said it was meant for a boat that was having some clearance issues.

[HFarr]

I may be wrong about it. Not a prop designer, but if the diameter measurements are the same and it has a cup in it, it will have to have more surface area. Now if the start with a flat surface and and add cup and slightly let the O.D. shrink, then no.

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[larry_arizona]

My understanding is cupping reduces the diameter a smidge and is a secondary tuning feature to further optimize pitch.




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[repomannv]

Some really good info in this thread. I knew nothing about boats, let alone props before purchasing my 2021 SA 450... I just looked and I'm running a 16 x 17 prop, which is what my dealer must have spec'ed for me. We only wakesurf, and with a lot of weight on the boat, we have struggled to get the boat to maintain autowake desired speed (say anything above 10.5mph), particularly on heavy current/wind days. I'm thinking now I should swap out my prop to a 16 x 13.9 given our use case.