Jackplate Question

[chadbenton]

I have an 89 Cajun Espirit 175, with 88 150 XR2, 19p al. 4blade. It has a notched transom, my vent plate is set a little below the bottom line of the keel. I want to raise it to help with performance, and from what I have read with a notched transom it could be raised several inches above the bottom. Do any of you guys know if this is correct. If so, I would rather put a jackplate on the aid in finding the sweetspot, then moving the motor itself up and down. Thanks for all the help in the past, and look forward to hearing what you think.

 

[1nebel0]

Re: Jackplate Question

Well.........if you move the motor to high, you will need to cone the lower unit which could cost you around 500 from Bob's. Then you have the cost of the plate that could cost you $1,000 plus. I can tell you that you are only looking at maybe 5 miles per hour, sometimes more in speed gain...You can buy a fixed jack plate and just lift motor a notch or two but that would be it. I have one on a tunnel that makes a difference however again had to cone my lower unit and the cost of the plate... They are cool for sure and just depends on how much you want to spend to go a little faster...Remember when you add the jack plate you are adding more weight on the stern since the motor is sitting back further and can hurt you planning possibly. Good Luck

 

[chadbenton]

Re: Jackplate Question

I was looking at a manual plate, I can get one off of ebay fairly cheap. Main thing is does it need to be set higher. Also one dumb question on trimming, should the vent. plate basically be parallel with the bottom of the boat when fully trimmed, is there any short and fast rule to trim settings.

 

[Bondo]

Re: Jackplate Question

is there any short and fast rule to trim settings.

Ayuh,... Trim up til it porpoises, then tap it down til it stops...

 

[chadbenton]

Re: Jackplate Question

I knew it was a dumb question, just was'nt sure. That's what I usually do....

 

[Faztbullet]

Re: Jackplate Question

if you move the motor to high, you will need to cone the lower unit

This really only applys to a performance hull or speeds above 70mph. The Cajun hull is heavy like a Astro. The best set-up for that hull would be a 6" jack plate(may have to change steering cables)and a water pressure guage (to see if you start to loose water pressure). If you only want to fish and get max speed start with boat level and trim engine level. Lay a straight edge on bottom of boat "pad" and it should split the top 2 intake holes on lower unit. This is your starting point. Also dump the Al prop and borrow a S/S in a 21-22 pitch to start with....

 

[chadbenton]

Re: Jackplate Question

Ok, thanks for the info., that gives me a good place to start from. I was incorrect on the prop. it is a 21p Solas, but will look into a stainless. I do have a water press. guage installed...