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05-14-2010 | 01:34 PM

#21

phil_p999

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Joined: Oct 2008

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From: Belle River, Ontario / Lake St. Clair

Quote:

Originally Posted by tssteph

i personally picked up 9 mph with -2 shorties with no boxes and absolutly no other changes. With that being said my boat really frees up around 95 mph which is where I was stuck prior to the shorties. Mine is a 98 so is probably similar in weight to yours.

Also 95 mph at 5000 rpm with 30 pitch props and 1.50 drives would be zero slip. This is not likely. Some number somewhere must be off.

Brian, I was wondering that myself as I used that mercury prop caculator after I went out............ how accurate is a hand held GPS?

these cat are usally 6-8 maybe 10% slip???

Phil

05-14-2010 | 01:54 PM

#22

tssteph

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From: Cincinnati, Ohio

Handhelds are accurate. Check your ratio first. Based on the bottom side of the hatch your boat may have had blowers at some point so the ratio may not be 1.50. If it is 1.36 then your slip is reasonable and your speed is reasonable based on the data you provided. If they are 1.50 then I question rpm.

Slip depends on the boat. A wise man once told me to work on slip first and the speed will come.

05-14-2010 | 02:37 PM

#23

Ran-Dom 32

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From: Lake St. Clair

I also believe he has 1:36 ratio, My Buddy's 31 Awesome w/500efi's 1:36 with stock 30P (not labbed) no boxes, runs 92-93 @ 5100 ish , correct me is I'm wrong Bill.

, so having labbed B1 & boxes netted him a couple MPH