Another jack plate question.

So I have a 12 V bottom and a 7.5 Mercury motor.
The tiller handle is to close to my seat and the motor is over an inch low might be two. It's currently at shop. I just got the motor and haven't ran it yet.
But I'm thinking about building a Jack plate to set it back and up some. Question being how far back would I want it for best performance. 4 inches I think would still be comfortable to reach the tiller.
I'd assum farther is better but is that true for such a small motor?
Is there a reason to keep it closer to the boat?
And if you've got pics of any home made ones I'd love to see them. Seen a really nice thick one on here last week but can't find it again to save my life.

For every inch of set back you can raise the motor 1/4".

I got to run my boat a little today. The nose runs a bit to high with the motor all the way down.
I pulled the pin and let the motor all the way down against the boat. And it put me almost level when running wot.
I want to run with the pin in a hole so the motor can lock down in rev.
Think the Jack plate will give me atleast that one hole back. Or should I twist the engine mounting side back a little before welding it.
Also read the off set will make the boat sit deeper when at rest. I don't need that!
Think it makes that much difference in the resting depth? It's a small motor but it's also a small boat :mrgreen:

I don't want to relocate my battery forward unless I have to. Il sacrifice speed first.

Is there any reason I can't make it six inches of off set?
That would be the most comfortable to run the tiller handle.
Heck eight would be nice. :mrgreen:

My new test plate. Or what ever you want to call it. Lol. Made from steel rectangular and square tubing. Weight 6 pounds. Seven inch off set, three inches of lift.
Does anyone think three bolts is enough to keep that sucker from twisting up or down and breaking the bolts.
I didn't want to make it any heavier buy adding a down brace. But now I'm thinking what if I hit something with the motor. Thoughts?

If this one works I've only drilled one extra hole in the boat.
And I can make one out a aluminum later. That fits it.
Thinking il run a safety cable on the motor just in case I break it off the boat. :mrgreen:

I would strongly suggest you not use that.
Please look at commercially produced units. Google "Dillon racing jack plate" Then sell plans to make your own the plans used to be free now $5.00.

T&H Mini Jacker.

Your design will concentrate the weight and torque to the top of the transom only. I don't think that's a good idea.

It should be distributed across the transom.

IL weld some flat stock pieces down off the bottom so it will be a square bolt pattern.
Theres a piece of Dimond plate covering the hole out side of the transom

Ok everyone relax you not going to get to see my you tube boat wreck video. Lol. I'm scraping my steel jack plate. It flexes the back of the boat to much even with a brace ran all the way to the bottom. Darn it.

So next question does anyone see a problem shimming the motor up? With a one inch piece of sqaure tubing under the motor to lift it one inch. It puts my hold downs rite at the top of the transom. But seems strong enough. I could bolt the bottom of the motor down.
Here's a pic. Note that's a short scrap piece of tubbing il cut one longer.

Is it going to give you what you want or need?

[Before you drill holes in the transom]

With the engine tilted down take some pictures that show the keel in relation to the engine / cav plate.

A straight edge against the keel running past the engine would help

Its closer but still needs to go up a little. This is a good angle of it.
It will be a while before I can get the alumnuim to build a real Jack plate. And it isnt going to line up with those holes. But atleast there above the water line.
Do you think one inch will be that much gain performance wise?

Put the shim under it, run it and see how you like it.

I don't think you'll get much benefit.

With the setback you get from a jackplate you'll get a couple of inches.

On my build I put a 6" jackplate on and raised 3+ inches.

Even with the extra weight [100 lbs] I added to the boat I probably got another 2 mph.... And I love the fuel burn - 7.5 miles per gallon.

ETA:

You might find some 1/4" plate angle at a scrap yard on the cheap. That will work with a 7 1/2 hp no problem.

3" angle will get you a 4" setback easy - maybe almost 6"

SumDumGuy said:

Put the shim under it, run it and see how you like it.

Click to expand...

That's what I did before I decided to get a T&H mini jacker.

Thanks for the help guys!
I went ahead and drilled the holes for now. What's a couple of holes in a boat that has no motor because it hit something and fell off. :mrgreen:

I'd sure like to hear the results of your next runs.

CMOS

It wouldn't plane out. Blamed the motor for running poorly.
Then as I pulled into the drive way it hit me I never pulled the pin out. And let the motor all the way down like I did last time. Duhh
Lol.
I'm going again this week end. IL let ya no.