400 with 1.76 transmission prop choices

[larry_arizona]

I think a 16 fits a Moomba, but I recall prop burn is possible.


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[dakota4ce]

I think a 16 fits a Moomba, but I recall prop burn is possible.


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It “fits” but will definitely burn your gel.
Would need to install a protective plate to guard against the burn.


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[larry_arizona]

Probably can just 5200 on a piece of stainless steel.


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[sleek98]

Thanks guys, I assumed there had to be a reason they went with a 15.5" instead of the 16".

[cwfehr]

I have the Acme 3591 with.105 cupping on my 21 SL 450 with 1.76 trans. We surf with full ballast, 800lbs of lead and a small crew weighing about 520lbs. Pitch is between 9.5 and 10.5 and speed is 11.2 or 11.4 mph. Elevation is 2820ft. RPM's vary a bit due to current and chop, but pretty consistently between 3450 and 3750. I get noticeable steering wheel shake at launch, which I assume is the force of the water the prop is sending past the rudder. Anyone else experiencing this?

Also, coming off the throttle, right before neutral there is a small rattle (noise no vibration felt). No idea what this is but it is annoying me...worried there is something loose but can't see anything on the shaft and prop looks fine. Prop was refurbished and balanced. I have a second (new) 3591 that I could swap out I guess and see of that makes a difference, but maybe you all have some ideas?

Cheers!

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[HFarr]

Are you sure your rudder is straight when you launch? I have sometimes noticed if I have it turned too far on initial launch I get a funny feeling. Lot of force hitting it on the side suddenly if it's a full throttle launch and it's (the steering wheel) turned.

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[Hayden]

I have the Acme 3591 with.105 cupping on my 21 SL 450 with 1.76 trans. We surf with full ballast, 800lbs of lead and a small crew weighing about 520lbs. Pitch is between 9.5 and 10.5 and speed is 11.2 or 11.4 mph. Elevation is 2820ft. RPM's vary a bit due to current and chop, but pretty consistently between 3450 and 3750. I get noticeable steering wheel shake at launch, which I assume is the force of the water the prop is sending past the rudder. Anyone else experiencing this?

I get this with mine also, very similar setup in terms of weight, elevation, rpm's. Not so much that the steering wheel is shaking but that the rudder itself is cavitating heavily and that that cavitation is moving up the steering cable and felt, to a degree, on the steering wheel.

[cwfehr]

In most cases the steering wheel will not be straight. You are right, if it is straight the effect is minimal relatively speaking.

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[snowboardintahoe]

I am looking for the measurement from the middle of shaft nut to hull from a Supra so I can make a decision on running a 16in prop on my 2021 Moomba max.

If the measurements are the same or extremely close I would love to run a 16 inch prop.

I’m at 6200ft and can use all the help I can get.

[KnoxMojo]

2021 Moomba max.

If the measurements are the same or extremely close I would love to run a 16 inch prop.

I’m at 6200ft and can use all the help I can get.

Read reply #72, you can, but you'll need to install a stainless plate to prevent prop burn. Dakota has a 21 Max.... I'd run like a 15.5x12 or 15.5x12.5 on it.