Jack Plate Height

[Jryley]

Hello, I was wondering if there is any rule of thumb or anything to setting the height on a jack plate. I've got a 21' triton with a 225 optimax and a 6" manual jack plate. The problem is that when I get up to faster speeds (around 65) its starts getting real squirly. I'm almost positive that is what it is because I've tried it out at a couple different heights and some are worse than others. I've got it trimmed at the right height and everything. like I said i can only get about 65-67, and I should get about 80 or so. Thanks

[jdw174]

Not trying to be a smarta** here, but the only way you'll see 80 out of a TR21 with a 225 Opti is going down the interstate.  If you call the factory they'll connect you to someone who can definitely put your setup in the ballpark.

Jackplates need to be adjusted just a little at a time....a real PITA if it's a manual plate.  Sometimes as little as 1/4" can make a difference.  If your TR21 is an older model, they were known for their chine-walking which sounds like what you're experiencing.  Seat time will help you to learn to drive thru it.  A proper setup will help alleviate most of it.  You may want to experiment with props also.  Properly set up, I would expect your rig to be a low-mid 70's outfit with a full load and running flat-out.  You didn't say if you have a GPS to check speed, but most Tritons I've seen (I own one) are 5mph fast on the speedometer.  The newer hulls (X2 series) supposedly don't chine-walk and are much steadier to drive.  They're also a tad slower than the older boats.

[Jryley]

Ok thanks, I just know I have throttle left and I cant get wide open without it chine walking. ill check out that site and just keep driving it. and yes its GPS speed.

[Way2slow]

Height is going to depend on the prop your running and where you start loosing water pressure at.  Yes, the more of the lower unit you can get out of the water, the less it will chine walk.  

Do Not raise it any higher than the motor can maintain 16 psi of water pressure at WOT and trimed out, even in the turns, you can fry your motor if you do.

Some props will loose too much lift if you raise them high enough to get the water pressure down to 16 psi so you have to watch for that.  Dialing one is paying attention to the tac, speed (gps, not speedo), water pressure and bow lift while making 1/4" adjustments up on the jackplate.  Once you start loosing lift, too much water pressure or speed, or the tac gains rpm but the boat does not gain speed, you drop it back down 1/2"

I'm not sure what the max offset you can run without voiding the hull warrenty but I would have thought it would have been more than 6" and I would think on a 21' boat, it would need more.  However, the more setback you run, the more it will want to walk.

Chine walk is a fact of life with your boat, once you get the setup perfect, you are still going to have to learn to drive it, and that want be no two or three trips to the lake.

To save a lot of work and agrivation, and the Toons are very propular boats, I would suggest you try several of the sites and ask what they are running for a setup (prop, setback, prop height etc) with you same outfit.

Not real sure you will see 80 mph but you should get well into the 70's.  I was running 76.7 gps Sunday and it took me a good ways to pass a Triton with two people in it so I figure it was running close to 75.  We were not real close so I didn't pay any attention to the size of the boat or the motor, other than it was a Merc 225.

[burleytog]

Chine walking + high speeds + blast-off = tons of fun!  ;D

That feeling of being both in and out of control is exhilarating.