Jack plate for trolling?

[fishin4fun]

If I install a hydraulic jackplate between my Merc F115 and my 18 ft
Harborcraft, Will the boat troll at a slower speed at idle when the motor is raised as opposed to the normal fixed mount position?

Just wondering.

[fishin4fun]

Come on all you guys with jack plates...Hasn't anyone tried this???

[WallyHunter16IL]

I dont yet have a Jackplate, still deciding whether to put one between my 115 Merc. and my Astro bassboat. I dont think raising your outboard would slow you down. I think your trolling/ idling speed would stay about the same. The jackplate would give you more mph & rpm's at full throttle, but trolling im not quite sure. Someone should be able to help ya out! Take Care.

[ETT]

I don't have a jackplate but, your idea will work, in fact just using the trim to kill the efficiency of the motor will rub off a couple tenths. The potential problem is that you sure don't want to pull the water intake out of the water and starve the water pump.
good luck, and good fishing.

[fishin4fun]

OK I have received two answers from people who don't have a jack plate and I do appreciate it.

Now let me refine the question...

My boat idles at about 3mph with the motor mounted normal height.
If I install a jackplate and raise the motor so the antiventalation plate is at water level, this will place the prop behind the transom in a much less efficient position. How much reduction in speed can I expect?? I would appreciate an answer from people who actually have jackplates. I understand about keeping the water intake ports submerged.

Thanks

[JAK]

With the engine in about a normal trim position, you will not get the engine to travel high enough to acomplish what you want.

Most plates allow about 5-7 inches of vertical travel. You can also effect high high they go by where the plate is bolted to the engine and in turn where the engine is bolted to the plate.

If you bolt both the engine and the plate as high as they can go, you may not be able to lower the engine far enough for normal running conditions. It would be close. Having said that... with everything as high as it can go you most likly will NOT get the anti-cavitaion plate above the water line while at rest.

Take a look over the back of your boat. How much water is above your plate normally? 7 inches? ...8 inches? ...more?

Most plates are set up to give about half the travel up and the other half down. If you have a plate that has 6" of travel, that means only 3" going up. Granted, you can play some games with how high it is bolted and will get the engine higher, but you will loose the ability to lower the engine far enough for good hole shot and for rough water ride.

Also keep in mind that that if you do get it high enough to slow your rate of speed, that the engine noise will increase!!!