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Adjustable jack plate for my Duck Invader with a 20hp

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Adjustable jack plate for my Duck Invader with a 20hp
So I was talking with Nick Zito yesterday, and he is trying to make me spend more money!
We were talking about navigating in shallow water, and it would be nice to motor in, instead of poling or walking the boat in.
Does anyone have any ideas about using an adjustable jack plate. I saw some that are manually adjustable with a crank that looked good to me, Nick thinks we need hydraulic.
My outboard is a 2018 Suzuki 4 stroke 20hp. Electric start, NO power trim/tilt.
Thanks





Oxford, CT
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Re: Adjustable jack plate for my Duck Invader with a 20hp In reply to
I have electrical driven hydraulic backplates on my 19 foot Bankes crusader with a 115 hp Yamaha and 17 foot polarkraft tunnel boat with a 60 hp Yamaha. They really help dial in the engine height for maximum speed and for adjusting engine height to the water depth in shallow water. But the range of travel is only 6-8 inches. This really is useful with the tunnel boat and I use it occasionally in the bigger boat to get that last 2-3 mph out of the hull. They are made of 1/2 inch thick aluminum and have an electric motor/hydraulic pump and actuator so they are not lightweight. The ability to run shallower is modest (1-6 inches) and the extra weight on the transom may offset that shallower draft. I like the ability to change the vertical position on my boats. I am not sure I'd do it again on my aluminum tunnel boat given the squat caused by the weight. I could just permanently mount the engine high on the transom. But it is a tunnel boat so I start from a stop with the motor fully extended down for hole shot and then when I am on plane and either wanting to increase speed or decrease draft I'll raise the engine to the point that the prop is operating in the tunnel and the skeg extends below the hull by only a few inches. I probably wouldn't do it on a smaller boat.
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Re: Adjustable jack plate for my Duck Invader with a 20hp In reply to
I'm just lazy mike. The thought of trying to manual crank up my DF40 (250ish lbs) sounds awful. I already tore my bicep moving logs, I'm trying to learn from my mistakes and work smarter not harder! Running 6" shallower doesn't sound bad. I already run pretty low if I trim the motor up. That trim and tilt hydraulic jack plate might get me lower!
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Re: Adjustable jack plate for my Duck Invader with a 20hp In reply to
Nick Zito wrote:
I'm just lazy mike. The thought of trying to manual crank up my DF40 (250ish lbs) sounds awful. I already tore my bicep moving logs, I'm trying to learn from my mistakes and work smarter not harder! Running 6" shallower doesn't sound bad. I already run pretty low if I trim the motor up. That trim and tilt hydraulic jack plate might get me lower!



Adjustable Manual Boat Jack Plate - High Grade Marine Aluminum - for up to 30hp Outboard Motors - by On The Fly Jack Plates https://smile.amazon.com/...oding=UTF8&psc=1


This looks interesting. my 20 hp is less than half the weight of yours, and I'm not old like you Cool





Oxford, CT
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Re: Adjustable jack plate for my Duck Invader with a 20hp In reply to
Sucks getting old. Everything breaks. And. It just on the boat!
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Re: Adjustable jack plate for my Duck Invader with a 20hp In reply to
Nick Zito wrote:
Sucks getting old. Everything breaks. And. It just on the boat!

As I typed my last reply, I had to stop to take Alieve for my elbow that's hurting.
Ha ha.


Now I'm just thinking of mounting my motor up a few inches and calling it good.





Oxford, CT
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Re: Adjustable jack plate for my Duck Invader with a 20hp In reply to
How high can you set it? Is there a guide to reference?
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Re: Adjustable jack plate for my Duck Invader with a 20hp In reply to
yeah I have tilt and trim on both engines. So if you don't then I'd think that would be a good place to start. There are add on tilt-trim units that would allow you to mount it higher on the transom and get the functionality of tilt/trim without buying a new engine or retrofitting to get OEM tilt/trim.
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Re: Adjustable jack plate for my Duck Invader with a 20hp In reply to
On my Estuary there was a piece of 1?1 wood at the top of my transom similar to this. I never thought about it until I took off the motor when I got my new boat.





Oxford, CT
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Re: Adjustable jack plate for my Duck Invader with a 20hp In reply to
I had to do the same on my BBSB when I went from a Johnson to Yamaha. Being the engineer that I am, I cut multiple shims, and made several passes with each shim in each pin location and plotted the results then selected the best total height and made a single shim that was screwed and epoxied to the top of the motorboard. I also ran a couple bolts through the motorboard to bolt the motor in place as I was not trusting just the screw clamps from vibration, and thieves.

Dave Diefenderfer
Manassas, VA

"Once you set out to build a boat, throw away your square. And if you work on her after she's launched, throw away your level." author unknown

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Re: Adjustable jack plate for my Duck Invader with a 20hp In reply to
So if I get a Jack plate like this. How do I judge how high or low to set the outboard?
https://www.basspro.com/...BwE&gclsrc=aw.ds





Oxford, CT
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Re: Adjustable jack plate for my Duck Invader with a 20hp In reply to
Typically you want to mount the engine so that the anti-ventilation or cavitation plate is in the same plane as the bottom of the boat. But that is for normal operation. You can play with it. Your motor should have a series of about 5 mounting bolt holes spaced about 3/4 inch apart. Experimentation will show how high you can go before you loose hole shot or don't like the performance. Keep an eye on the motor temperature or the water tell-tale (i.e., pisser). If you raise it too high you might starve it for cooling water.
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Re: Adjustable jack plate for my Duck Invader with a 20hp In reply to
Look up on the fly jack plates. Manually powered for small outboards.
South Jersey
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Re: Adjustable jack plate for my Duck Invader with a 20hp In reply to
Mike,

There is a guy here in NJ, with the same boat as us, with a hydro-jacker. He runs a 1-2 year old Yamaha f25. I've spoken to him before. He told me where it really shines is in water that's 12" deep or so. He pulls the jack plate up (it's electric) so basically just the raw water intakes, prop, and most of the lower unit are in the water. Motors on slow right into areas he'd normally have to pole into. Goes without saying that with the motor up that high, you need to go slow. I've debated it but will probably wait until I upgrade to a newer 4 stroke. Few reasons why:

- My motor is a manual start Merc 25 2 stroke with no stator.
- It's about as light as it gets to begin with at 112 lbs.
- A lot of guys will get the plate to use a long shaft motor with a short transom. $800 is better than $2000 or so and the difficulty finding a SS 25hp.
- I would need to add a swing tongue to my trailer to fit in the garage. I know it sounds silly but it's the only place to keep my boat.
- With that, it does set the motor back another foot or so. You will need to use a tiller handle extension at all times.

If I was going to do it, zero chance I'd go with a manual crank one. No way I'd want to be leaning over, in the dark, cranking the motor up to get into 12" of water. With that being said, the manual one stands less chance of breaking on the water, leaving your motor up.

EDIT: I believe it's the TH Marine "Micro Jacker" he has.
Shoot me a message I can put you in contact with him on FB.

Last edited by:

Jay K: Jan 27, 2022, 4:58 AM
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Re: Adjustable jack plate for my Duck Invader with a 20hp In reply to
PM sent

I like that Micro Marine one.
I'm really liking it. I'll have to think seriously about one for next season





Oxford, CT
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Re: Adjustable jack plate for my Duck Invader with a 20hp In reply to
After today's adventure in the marsh, I'm 90% leaning towards getting the hydraulic jack plate. The mud was coming up fast, and I ended up poling and walking my boat around to retrieve a couple geese. It would have been much easier to motor around instead.
T-H Marine AHJM-4-DP Atlas Micro Jacker https://smile.amazon.com/...oding=UTF8&psc=1





Oxford, CT
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Re: Adjustable jack plate for my Duck Invader with a 20hp In reply to
Mike,

I have a similar, maybe slightly smaller manual jack plate by TSG Custom, single vertical adjustment screw and four side bolts to lock it in place. Mine is not an "on the fly", the assembly relies on the four side bolts for stability and trying to loosen and tighten up the five fasteners with the motor on from inside the boat isn't practical. It is good for optimizing the motor's position but not an "on the fly" adjustment. The TM version may work better but at that price, I'd recommend looking for an "on the fly" / crank or hydraulic version that doesn't rely on side bolts for stability.

Now the Rock-Hopper prop and skeg guard has been great in the rocky river.




The jack plate has let me swap out to a Suzuki long shaft (20") but I did have to fabricate a larger motor mounting plate to handle the larger motor mount. I'd volunteer to go out and take more photos but you know what it's like outside today.

Best,
Scott

Last edited by:

Scott Farris: Jan 29, 2022, 10:14 AM
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Re: Adjustable jack plate for my Duck Invader with a 20hp In reply to
Thanks Scott, yup we are getting some snow. Tough to judge with the wind blowing it around.
I definitely want a hydraulic jack plate. That part number on Amazon is for a hydraulic jack but the picture sure doesn't look like it's hydraulic
Thanks for the information





Oxford, CT
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Re: Adjustable jack plate for my Duck Invader with a 20hp In reply to
Mike

Here are my jackplates. They work well but are probably overkill for a 20 hp.

This is a 60 hp on a 17 foot tunnel Jon boat.



And the same jackplate lifting a Yamaha 115 hp on a 19 foot Bankes.