400 with 1.76 transmission prop choices

[Stazi]

Probably +8% all round if slip I the same.


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[SONIC]

The prop calculator I use is showing about 200-250 rpm increase with the same slip.

[Stazi]

That’s 8%.


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[SONIC]

Pretty much yep

[Shoebox]

@Shoebox what's your drive ratio?

I'm 1.76 : 1 and run about 3200-3400 at surf speed on the 16x15 prop full ballast

1.76. I also have 1k lead.

[larry_arizona]

I would be happy surfing at 3600rpm with a 16x13.9

Do you have the prop slip calculator?


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[SONIC]

https://www.rbbi.com/folders/prop/propcalc.htm

Here you go, good to play around with.

[DNIXD99]

I thought lower Pitch was supposed to produce lower RPM, and lower Top Speed.

[DDNorCal]

I was just up at Tahoe with 3k of people and lead and running 3800 rpm at 11.4.

[Isaguel]

I would think the 16x15 would be sufficient. I run the 16x17 now and all 100% full ballast+ 500 lbs lead distributed evenly side to side + crew of 4-5 adults and I have not experienced any lag pulling a surfer. 400 engine. I thought it would be necessary to go down to 16x15 but have not been hurting for it. I do plan to get a second prop and it'll be 16x15 but frankly, not out of necessity. Just my 2 cents.
I just cant imagine what I'm gaining by moving down to a 13"pitch. Loose speed, increased RPM. Considering how my boat handles it now, I just don't see the payoff for what I'd be giving up.