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Do I need a jack plate

R

red314

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I have a 1989 ranger 396v with

I have a 1989 ranger 396v with a 200 H.P. outboard mariner. I bought this boat last summer. I got a nice suprise when I opened it up on the water. The boat will do 60mph no problem but wants to take a very hard right hand turn which is not to safe. The trim tab was gone so I put a new one on and moved it to either side and no luck. The motor must have alot of torque at high speed which is doing this (my best guess) at low speed no problem. Is a jack plate needed or do I need to relevel the motor or live with it? The prop is a 4 blade SS quick silver not sure on pitch. I did notice on hard turns it looses its bite.
 
Randy can you post a bit more

Randy can you post a bit more info.
prop pitch
Max rpm
Engine height say cav plate in relation to bottom of boat
type of steering .
The natural torque of the motor will make it turn right but it shouldnt be unbearable.
 
"Off the top of my head I woul

"Off the top of my head I would suspect that you have something "unbalanced" on the boat which is causing the severe "swerve". (Another alternative would be a hull defect)

What I mean is, if the batteries are located on the starboard side, plus things like side gas tanks (starboard full, port empty), livewell full of water etc etc, plus "you" the single passenger on the starboard side - the "right" side of the boat could have 600-700 pound more weight on it than the "left" side. That alone will cause a big swerve to the right.

So yes, a standard rotation motor will naturally torque to the right, but that can be easily compensated for with trim tabs and/or redistribution of weight.

And just shifting weight would be my first "test". Put 300-400 pounds of "stuff" on the port side (or a very large friend in the passenger seat) and see if the torque to the right is still as severe....

A Jackplate is used for very fine tuning of performance and personally think that any boat longer than about 16 feet or pushed by more than about 125 horses, is served well by having one installed, but it will not correct an unbalanced situation, in fact, it could make it more pronounced - it's used to "perfectly" trim the motor to the particular hull it's mounted on...."
 
"Thanks for the replies.

Th

"Thanks for the replies.

The boat has 2 fuel tanks one on either side of the boat so I will try keep them full or around the same level. I am aware of the gear weight and try to keep it even.


The trim tab did not seem to help with moving it either direction.

Not to sure on prop pitch or rpm I am to busy holding the wheel to look at it to long.

I did try having the girl friend and 2 kids sit on the port side which did not do a thing

247995.jpg
boat pic
 
Have you noticed if trimming t

Have you noticed if trimming the motor up a bit reduces this effect?? Could be as simple as the motor is tucked too far under the boat driving the nose in exagerating the problem
 
"Randy, some other things I wo

"Randy, some other things I would look at if a rig with similar issues was brought to me would be -

look at the hull, check for any build-up/crud on the bottom which could cause additional drag

make sure the motor isn't "canted" a bit to one side - they guy who rigged it may have tied one on the night before - even an 1/8" out of (square) could have profound effects at higher speed - I would check to see that the motor bracket is snug to the top of the transom at both sides (no room to slip in even a popsicle stick from either side).

Also, make sure the motor is exactly centered on the transom (same reasons as above).

A couple of easy things to check out...."
 
"David, that's a real poss

"David, that's a real possiblity as well. This style of hull has considerably less "wetted surface" when it is wound right out compared to many others.

And yes, totally agree that any additional bit of drag will display a greater effect than may be noticed on another model.

One of the reasons for a jackplate is to get the motor up a little higher - less drag, a little more speed - almost standard equipment on bass boats now to help compensate for the fact less hull is actually in contact with the water.

Having said that though, it should still be possible to get the boat trimmed out without it pulling servely to one side, unless the hull has an imperfection, or the rigging was done incorrectly..."
 
"Yes agreee 100% Graham .Its s

"Yes agreee 100% Graham .Its surprising how many boats go past my place Fully loaded and fully trimmed in .
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David Thanks for bringing up

David Thanks for bringing up trimming of the motor. That is when the problem gets super bad. I trim out to the point the boat feals smooth and you get that quick scooting feal but than I have to hold on to the wheel in fear if doing a circle.

The hull looks like new the boat is in great shape. The motor does not have any marks on or around it like it was ever moved but I will look to see if it is level and take measure ments to see if it is square but that wont be for a while it is to cold outside to mess with it

Could the prop be doing this also? I have never had a boat with a 4 blade prop and unsure what advantage they have over a 3 blade. It came with the boat and I do not know much about props
 
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