Cole Hydro

[shirkey4750]

Have a friend who has a Cole Hydro, this boat is turning 7000 RPM, but won't kick the tail. It has a 11 1/4 x 17 cleaver with 25% gears(?). What should the clearence be between the prop and the strut? This boat has a 588 tall deck that is making 850 HP on the dyno with 830 lbs. of torque. It appears that the prop is extended out past the transom by about 1/4".

[Kurtis500]

Have a friend who has a Cole Hydro, this boat is turning 7000 RPM, but won't kick the tail. It has a 11 1/4 x 17 cleaver with 25% gears(?). What should the clearence be between the prop and the strut? This boat has a 588 tall deck that is making 850 HP on the dyno with 830 lbs. of torque. It appears that the prop is extended out past the transom by about 1/4".
Check motor placement and weight distribution. If its doing that RPM with that combo it must be bucking pretty hard to get the tail up if it still cant do it....

[bigheavyd2]

Hey Shirkey 4750 Is your friend running inboard sterring or outboard, prop should be no more than a 1/4 from the strut, prop might be to small, I run a 11 3/4 x 17 at 8000 RPM with a 588 BBC at 145 MPH blowing the tail. need more diameter thats what give you more lift. if you have inboard sterring going to be hard to get her to blow the tail. little bigger prop and 1000 more rpm and your there. heavyd

[shirkey4750]

Its outboard steering, with a 11 1/2x 17 precision clever.

[bigheavyd2]

See if your friend can barrow a 11 3/4x 17 to try, then what you can do is spit the coulper and put a nickle between the two shafts, it puts the prop more in the water and back!!!! I learn that trick from RB that what they do to there top fuelers. and it WORKS. If the boat not blowing a R tail the props not ridding on top of the water. heavyd

[BUSBY]

Another thing to think of is about the blast plate ... I have my prop set at 1/2" from the strut ...
You say that the prop (tip?) is 1/4" past the transom ... but is it still under the blast plate?
If the prop is shrouded by the plate, it will make it harder to blow the tail quicker.
Engine placement is a key factor ... getting it too far to the rear and you'll never blow the tail. Did it ever before? Something to think about.

[Kurtis500]

The tail of my prop extends back to the transom, but my blast plate goes another 2 inches or so beyond.
I'm guessing weight distribution is the reason. I moved my battery from behind the motor to the sponson and it alone made a difference. A motor to far back and/or a battery and/or a 10 gallon tank full of fuel in the back can keep the tail in the water with marginal HP.

[bigheavyd2]

Kurtis is wright, weight distribution has alot to do with it when running margrinal HP, your motor should be around 44 inch from the transom, Im running 2 10 gal, tanks 1 on each side, boat weights 2020 lb. loaded. Im running a river rat not a full blow race boat.

[whiskey & water]

Maybe this may help a little, here is mine its a 1987 cole
http://www.***boat.net/hbcove/37/3/05.jpg
Here is a clip of one of my runs. I run the same size prop as your friend the motor in the video is a 427 blown on alcohol its problably set at about 1100 hp click on the bottom address.
http://www2.***boat.com/image_center/data/500/2748Joe_2nd_pass_1_Sac_04.avi

[Bad Meds]

Did it blow the tail before and now it's not ? Or has it never lifted the tail with this combo ? Just an FYI , just because the prop says it's an 11 1/2 -17 doesn't mean that it is .Do you know the history on the prop ? How old is it ? Has he tried different props ? Detailed pictures of his set up would really help .You said the prop is 1/4" past the transom.Is that the tip of the prop or ? How close is the tip of the prop to the bottom of the boat ? You said it's running 7000 rpms .When does it get to that rpm ? Does the prop burn to that rpm and stay there ? Does he roll into the throttle or is this a stand still full throttle start ? I think we need some more info :D

[BUSBY]

Did it blow the tail before and now it's not ? Or has it never lifted the tail with this combo ? Just an FYI , just because the prop says it's an 11 1/2 -17 doesn't mean that it is .Do you know the history on the prop ? How old is it ? Has he tried different props ? Detailed pictures of his set up would really help .You said the prop is 1/4" past the transom.Is that the tip of the prop or ? How close is the tip of the prop to the bottom of the boat ? You said it's running 7000 rpms .When does it get to that rpm ? Does the prop burn to that rpm and stay there ? Does he roll into the throttle or is this a stand still full throttle start ? I think we need some more info :D
Hey Mikey B! What's up ...
Good questions there ... those are they next ones I was going after (some of the ones you helped me out with) ...
Shirkey ... you're in good hands here ... you have the attention of some real experienced (and fast) hydro guys ... now is the time to get your data together and ask all of your questions ...
Just my .02 ...
Brian
P.S. ... not to jack the thread ... but Mike, PM me your phone number ... I want to see if you might have some gears I can try for the next race.

[BUSBY]

The reason I ask about the blast plate is that when my hull was rigged originally, there was 4" of plast plate installed beyond the transom by the previous owner and that left the prop sheilded. After a visit by Ron Braaksma, he advised me to make it 1/2 of that leaving only about 1/8" beyond the 2" angle aluminium that it bolted to. Now ... take note that I couldn't get the tail to blow completely before the mod and with that change alone ... it blew the tail everytime.
He was very helpful in that situation ... however there were a lot of questions that led up to that decision ... like the ones Bad Meds is asking ...
Good Luck.
Brian