# Mini-jacker ???



## truckhuntfish (Mar 25, 2011)

I am looking at getting a mini-jacker from BPS and was wondering if anyone has one of these ?
I have a long shaft motor on a short shaft boat and seen these for a quick/easy fix.

If you do , what is the height of the mounting flange(where the bolts go through) that mounts to the transom ?

Also , did it NOTICEABLY help with the perfomance of planing out etc. ?

Thanks ahead for any replies


----------



## lckstckn2smknbrls (Mar 25, 2011)

I have one on a long short shaft motor on a 15" transom. The river I'm on can get very shallow.
There are series of dimples on each side it that you drill out to get the proper fit.


----------



## Pappy (Mar 25, 2011)

In your case, with the mismatch of shaft length vs transom height the performance difference should be very noticeable. Try and mount it to where the cavitation plate is about even with the bottom of the boat measured when the plate is parallel to the bottom not trimmed in or out. That would put the jack plate higher than the transom as a starting point am guessing. I have one on a 13' Gheenoe and just installed a Bob's Machine Mini Adjustable plate on another Gheenoe.


----------



## Bobg (Mar 26, 2011)

I've made several jack plates using 3x3 aluminum angle, spaced wide enough for the engine, and high enough, so that the anti-cavitation plate above the prop is lined up with the bottom of the hull.

Mount the angle to the hull and put in the transom boards you need. I used 3 pieces of 3/4 plywood to get the 2 1/4 inch thickness of a transom. Not all transoms are that thick, but 2 1/4 is about all the thickness you'll need. I glued them together over night, and mounted the transom board the next day.

Mount the motor and measure up from the motor plate to the bottom of the hull and that will tell you how high to mount the angle sticking up above the transom.

The last one I did was for a 25 Merc because they measure 18", not the 15" or 20" that most other motors measure. The mini jack plate shown above is only a 3" rise I believe. If you need 5" it's cheaper and you get what you need if you can make your own.


----------



## truckhuntfish (Mar 27, 2011)

Thanks for the replies , I ordered it already and it should be here this week sometime. when i bought the boat , they used a 2" x 2" piece of wood to raise it up. was thinking about mounting top of jacker mount flange even with top of transom and re-using 2 by 2 again in case i might want to move it up or down in the future. but i could just move jacker too i guess.

I just bought the boat from a friend and took it out for about 5 mins to make sure everything worked. He told me everything worked fine but the motor needed to be raised up. i probably wont notice a difference.

this is my first boat ever and i think i got a good deal SO FAR.


----------



## Pappy (Mar 27, 2011)

Instead of thinking why not measure? You have two replies that indicate you will probably be above the transom to start with. Of course theres that old saying about never having time to do it right but always have time to do it twice! Without me measuring, am betting once again that your top of the mount flange will need to be (a minimum of 2-3") above the transom. There are dimples in the plate that can be used as drill guides for raising the plate. Use them! Your thinking would be closer if you had a 15" engine to start with, you don't. Most cavitation plates are at least an inch below the bottom of the boat plus your engine is 5" too long to start with so there's a minimum of 6" just to start with to bring your engine close to where it needs to run.


----------



## truckhuntfish (Mar 28, 2011)

I put the motor back on , put a level on bottom of boat (for a straight edge) and measured the difference. cavitation plate is 5 inches from bottom of boat.

I probably will still want to put a piece of wood ( 2 x 2 ) on top of plate right ? to keep motor and plate from rubbing together ?

3 inch rise from mini jacker + 2 inch rise from 2 x 2 = 5 inches 

should do it. right ?


----------



## Bobg (Mar 28, 2011)

BOLT that engine to that jack plate when you get it mounted.

Mount that jack plate as high as you can to get as close to the 5" that you need for the best performance. It looks like your jack plate will set the engine back about 3", meaning you could go another 1/2" higher.

Looking at that jack plate, I can see mounting a transom board to it to get the height you need. Anchoring the top of the board to the jack plate, with two bolts wider than the engine mount, and using the lower holes in the engine mount to anchor the bottom portion of the board, using two more bolts through the engine mounts, jack plate and board. This would eliminate your need to shim it 2" higher, and give you a more stable surface for your engine.

Thumb screws would be biting into wood, and bolted at the bottom.

Watcha think, Pappy?


----------



## Pappy (Mar 28, 2011)

There is nothing wrong with mounting the flange of the plate higher than the transom to start with. It is made to do that. That plate comes with wood on the inside of the plate to mount the engine with. I say mount the plate at the right height to begin with. There is plenty of support for the plate and engine if he has the wood on the inside of the transom for (4) plate holes through the transom. Would like to see the cavitation plate around 1" above the bottom if possible. Again that measurement is made with the plate parallel to the bottom and not angled down or up. Engine will only need its clamp screws and the two optional mount screws to be secure. You do not want to place a 2 x 2 above the plate to keep the engine from rubbing. That is a non issue and will place additional stress on the clamp screw geometry of the engine brackets. Small engines have been mounted right on the tops of transoms for the last 102 production years with no issues.


----------



## Howard (Mar 28, 2011)

Can you use this plate for the reverse situation? I have a 17" shaft on a 20" transom. I need to lower my motor.


----------



## nathanielrthomas (Mar 28, 2011)

Howard said:


> Can you use this plate for the reverse situation? I have a 17" shaft on a 20" transom. I need to lower my motor.


 

I dont advise it. Itll work, but its aggravating. you cant tilt your motor up all the way


----------



## richg99 (Mar 28, 2011)

Perhaps you two guys (Howard from GA and the OP from WI) could swap your motors..... Rich


----------



## lckstckn2smknbrls (Mar 28, 2011)

The reason you see a 1" wood shim in my pictures is that I was experimenting with different motor heights. I have remounted the mini jack plate higher.


----------



## truckhuntfish (Mar 28, 2011)

OK , Thanks for the replies , I was probably making more out of it than i needed to but just wanted input from people with more experiance than i have.

Thanks again


----------



## clarkbre (Mar 28, 2011)

Here's my two cents: 

I had the same issue of a longshaft motor on a 15" transom boat. I looked into the jackplates but none of them looked that great. So, i decided to design one specific for my application. Here are the results:

The riser is 6" taller than the transom and sandwiches the transom both inside and outside of the boat. I used (4) 3/8" bolts to mount it to the boat and the motor clamps to the riser.


----------



## Howard (Mar 28, 2011)

> I dont advise it. Itll work, but its aggravating. you cant tilt your motor up all the way


 Ah, didn't of that. Im down to that or cutting the transom. Maybe tradeing.....


----------



## truckhuntfish (Mar 28, 2011)

looks nice clark , would you trust a 30 hp motor on that ?


----------



## nathanielrthomas (Mar 28, 2011)

Howard said:


> > I dont advise it. Itll work, but its aggravating. you cant tilt your motor up all the way
> 
> 
> Ah, didn't of that. Im down to that or cutting the transom. Maybe tradeing.....



I cut mine down, and it worked out great. Here is the link:

https://www.tinboats.net/forum/viewtopic.php?f=21&t=12719


----------



## Howard (Mar 28, 2011)

> I cut mine down, and it worked out great. Here is the link:



Thanks, I can not use the mini jacker. It does not allow enough room for the turn handles unless I want to I fur it out myself. My only concern with cutting the transom is weakening it. Yours looks great btw. Looks professional.


----------



## richg99 (Mar 28, 2011)

With regard to cutting down the transom...many of the Carolina Skiffs wind up with their transoms cut out to accommodate a shorter shaft motor. Of course, that is pretty thick fiberglass. I don't doubt that it can be done on any sturdy boat, though. 

However, it might be a lot easier to just sell the short shaft motor (especially since it runs so well) and then just buy the right length motor to fit your boat. Rich


----------



## Howard (Mar 28, 2011)

Thanks Rich, buying a used motor is a roll of the dice and this one runs so well. This was given to me by my nephew so probally looking at cutting transom.


----------



## richg99 (Mar 28, 2011)

IF you happen to be anywhere close to Waycross GA....Carolina Skiffs are made there. As I said, they cut down transoms all of the time. Perhaps you can get an idea or thought from them. regards, Rich

https://www.carolinaskiff.com/about.html


----------



## ditchen (Mar 28, 2011)

Another piece of info you need when mounting a jack plate. A rough baseline is for every 1" of set back the motor height should be 1/2" higher. So if you use a set back of 6", ventilation plate should be approx 3" above the keel.

That is usually a good baseline to start. Application and total package combo will vary.


----------



## Pappy (Mar 28, 2011)

ditchen said:


> Another piece of info you need when mounting a jack plate. A rough baseline is for every 1" of set back the motor height should be 1/2" higher. So if you use a set back of 6", ventilation plate should be approx 3" above the keel.
> 
> That is usually a good baseline to start. Application and total package combo will vary.



Not necessarily! That "standard" started when plates were used mainly on faster deep V hulls (the old Gil brackets) and spread to the Bass market where the engines had specialized propellers and water pick-ups. Way not true on a small flat bottomed aluminum hull that may have an engine with a water pick-up at the rear bottom of the cavitaion plate or a more modern one on the side of the gearcase and well below the cav plate. These boats have no chance of airing out and running bow high like on a built in pad bottom or a 24 degree deadrise offshore hull. All rules do not apply on all boats and engines all the time. Even the 15" designation on a short shaft engine or a standard 20" is all over the place from manufacturer to manufacturer. You may find an inch or more difference between Johnson/Evinrude/Merc/Yamaha/Suziki/Nissan/Tohatsu, etc.


----------



## clarkbre (Mar 28, 2011)

truckhuntfish said:


> looks nice clark , would you trust a 30 hp motor on that ?



The one on my boat I would not. However, I would use a 30 if I beefed up the vertical plates. If they were stepped up to1/4" instead of 1/8" the riser would be plenty strong for a 30.


----------



## ditchen (Mar 29, 2011)

Pappy said:


> ditchen said:
> 
> 
> > Another piece of info you need when mounting a jack plate. A rough baseline is for every 1" of set back the motor height should be 1/2" higher. So if you use a set back of 6", ventilation plate should be approx 3" above the keel.
> ...



I used "rough baseline", not a standard. It is a useful guideline and I will agree with ya that "All rules do not apply on all boats and engines all the time". I also understand what hulls/outboard combos most are using here and modified v's and flat bottoms are not the same. 

I wanted to point out that the further that outboard is from the transom, the optimal position will be higher then if it was directly attached to the transom without a jack plate.


----------



## lckstckn2smknbrls (Mar 29, 2011)

The TH Mini jacker is rated to 35 hp.


----------

