props for 300x sutphen
05-01-2011, 09:34 AM
#1
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Location: Simsbury ct
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props for 300x sutphen
I was out yesterday and figured Id check my RPms and see how my props looked on my 31 sutphen.
Its a spirit model with twin 300x, sportmaster combo. Usually runs around 78 MPH but has been as fast as 82 MPH.
So yesterday , I was running back from LI and watched the RPMS and I was seeing 5730 based on a freind GPS in a boat next to me running 85 to 86 we figured I was running 82 to 83 at 5730. The way I was trimmed running back in about 1 ft or less chop.
In the river trimmed out pretty well, in flat water I was seeing 6370 RPM, No GPS so no Idea of MPH
I have bravo 1, 24 pitch, 4 blade props on the boat right now.
Anyone have any input or suggestions?
Its a spirit model with twin 300x, sportmaster combo. Usually runs around 78 MPH but has been as fast as 82 MPH.
So yesterday , I was running back from LI and watched the RPMS and I was seeing 5730 based on a freind GPS in a boat next to me running 85 to 86 we figured I was running 82 to 83 at 5730. The way I was trimmed running back in about 1 ft or less chop.
In the river trimmed out pretty well, in flat water I was seeing 6370 RPM, No GPS so no Idea of MPH
I have bravo 1, 24 pitch, 4 blade props on the boat right now.
Anyone have any input or suggestions?
05-02-2011, 11:19 AM
#5
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Neither does he! 
+1 for getting some real data from a GPS so you can see what's going on. You might have been running 83 at 5730 rpm, but you could have also been running 73 at 6370 with a lot more prop slip since you were playing with the jack height at the same time. You need to get some more detailed data before you start looking for something other than those 'fishin' props. Also, keep in mind the currents or tides can play games with the numbers.
+1 for getting some real data from a GPS so you can see what's going on. You might have been running 83 at 5730 rpm, but you could have also been running 73 at 6370 with a lot more prop slip since you were playing with the jack height at the same time. You need to get some more detailed data before you start looking for something other than those 'fishin' props. Also, keep in mind the currents or tides can play games with the numbers.
05-02-2011, 11:44 AM
#6
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true, also those 2 strokes just keep making more and more power with rpm, so you should really be propped right at the limiter. being able to move the bracket up and down is nice but it really makes it hard on trying to find a prop haha. that boat is light in the azz with the ob's so maybe going to a three blade mirage will help carry the bow without needing as much trim input.
05-02-2011, 11:44 AM
#7
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also, has anyone ever raced a 31 sutphen with ob's??????? maybe hearing their input would be able to help you out. if you really want the mph, put through hull pickups, jack them up, and run cleavers. when you start surfacing a mirage/bravo style prop it isnt going to like it
Last edited by 302Sport; 05-02-2011 at 11:47 AM.
05-02-2011, 01:00 PM
#10
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