Need to raise motor

[breausaw]

Taken directly from the Permatrim USA.
http://www.permatrims.com/category_s/12.htm

To verify the outboard installation height, trim your engine all the way down and take a straight edge and place it at the bottom side of the AV plate. Carry that straight edge forward and see that the straight edge is now level with the hull bottom.

From everything I have read having the engine at the right height is imperative for the Permatrim to function properly.

My engine needs to be raised up a notch to achieve proper high according to this statement taken directly form the Permatrim site, so how hard is this? I looked aft while the wife had the helm to see my Permatrim under water.
I know some brats have done this, and it can’t be that hard from looking at the bolt-on set up. The bottom bolts have a slot for adjustment and to top bolts have 4 adjustment holes. If I leave the bottom bolts a little loss and pull the top bolts I should be able to jack the motor up, run the top bolts back in and tighten everything up.
Realizing I have to use a lot of 5200 or 4200 in the process along with loosing up the motor for movement.

I know is looks easy but can’t be as hard doing a V8 long block swap, which I have.
.
If someone has raised their motor and has direct experience doing the job any helpful tips would be great!

Thanks...

[AK-Brando]

Never raised a motor before, but I figure I can put in my $.02 worth anyway!

I would venture a guess that it would be ok to do what you propose, but I would also add a thin strip of material (starboard, perhaps?) along the top of the transom to fill in the gap that you raise the outboard. I know there is a lot of torque and stresses where outboards mount, so I would think "shimming" the top of the transom could only help keep the outboard from slipping down again.

Glad to see another Alaskan on the boards!

[Dora~Jean]

I did it with my Yami 80's, 2 holes up. I simply put a wood block between the skeg and my hydraulic floor jack and lifted VERY CAREFULLY about 1/4" at a time while checking for any binding, etc. I did the same thing, removed the top mounting bolts then loosened the bottom bolts to allow it to slide. Hard part was resealing the bolt holes and reinserting the upper bolts while ensuring a good seal.

Good luck!

[Catch 22]

yeah this is not hard, and doesnt take too long either, ive installed a few motors, just put one on my boat, the only thing i can say is that i seemed to have notices on a few boats, when the motor is directly on the transom cap, the the vibration can eventually crack the transom top, letting water in and rotting out the transom, i think its fine if you have a small gap between your motor and the transom cap, no shim necissary....

[AK-Brando]

I stand corrected.

[Wandering Sagebrush]

Jay,

I would be interested in hearing the results in performance if you do change engine height. To be truthful, I ignored that when I installed the Permatrim on Constant Craving. My speeds and economy seems to be much the same, and I am impressed with the degree of control that I now have over the fore and aft attitude of the boat.

The only thing that I would remotely describe as as undesirable is a tendency to torque turn with lots of throttle/speed and the engine trimmed all the way down. It goes away as soon as the engine is trimmed up.

Steve

[thataway]

I probably need to move my motor up two holes, but the slottled lower "hole" will only allow one. We have considered using a tractor front loader with a chain to pull up the engine--seems easier than a jack, and safer.

I used to think that the transom support was necessary, but it is not. Almost all boats with the larger engines have the weight on the 4 bolts and no weight on the transom cap.

One of my concerns is that under certain condtions I will get cavitation with the current setup-- (the plate is about 3/4" below the transom)---and fear that the cavitation might be worse if we were to raise the motor too much.

[cemiii]

I read somewhere, i'll try and find it, that a good way to do this is to build up under the skeg with, for example, a concrete block, and then soft wood , like a 4x, with a skeg notch cut in it, then after bottom bolts are loosened (slightly) and top are removed, slowly jack up the front of the trailer with your hydraulic jack. In fact with the huge leverage, you may be able to lift it easily with simply using the trailer tongue jack. you can make the minor adjustments to seat the skeg on the wood with the trailer jack.

chris

[NORO LIM]

I recently acquired Permatrims. I think they are a significant help in adjusting bow attitude, lateral level (I have twin engines), and in maintaining plane at lower speeds. They do not seem to have reduced top speed or mileage in any detectable way.

I, too, was quite concerned about engine depth, having read what was available on the subject. To begin with, in my opinion the AV plate measurement is pretty arbitrary, especially with twin engines and any dead rise at all. I mean what exactly is "level with the hull bottom?" Figuring this out has got to be as much art as science. My boat has 5 degrees of deadrise at the transom, so the Permatrims on the twins are, of course, not centered on the lowest point. My best eyeball estimate is that the center of the Permatrims (which are horizontal) hits just at or minutely below the corresponding points on the transom lower edge (which is 5 degrees off horizontal). Of course, the Permatrims are still slightly above the lowest point (center) of the hull bottom. This measurement will, of course, be a little more straightforward with a single engine or a boat with even less deadrise.

I talked on the phone at some length with a guy (Stan?) at the Permatrim dealer about this engine depth issue. He said he was sure my engines as I described them would be just fine. He said not to take any offense, but with "slower boats" the depth issue is much less critical. (I took the comment as a compliment.) Apparently it's at speeds above about 40 mph that height adjustment can become really significant.

Don't have any independent corroboration for what I was told other than the excellent performance I've experienced with my Permatrims.

[Notayot]

[breausaw]

Brian and Kevin
My 90 Honda doesn’t rest on the transom cap, all weight is on the 4 bolts.

Steve,
We are thinking exactly alike; this is the approach I had in mind.

Chris,
Great idea

Bill,
Waiting to here back from Permatrim regarding this issue. I was going to talk with them before doing the lift, so if they think its not necessary guess I’ll bag it. What ever they have to say I’ll share it with the group.

Thanks for all the feedback..

[breausaw]

Talked with Andy Jr. at shipyard Island Marina, where I bought the Permatrim.
He said raising my motor to the point where the CP is even with the bottom would be ok; a notch above would be ok if running a stainless prop. Said the stainless has a better bight in shallow water where aluminum would probable cavatate.
Said raising the motor would defiantly produce better results but couldn’t suggest how much improvement I would see.
He also suggested Chris’s idea of blocking the skeg and raising the trailer to lift the motor, said he’s done this at the ramp.
I plan on raising the motor this weekend before our 3 day excursion next week, let you know the results.

[tpbrady]

Jay,

I get geometrically challenged at times so am having a hard time interpreting what Permatrim is saying. If I trim the motor down until the motor's cavitation plate is parallel with the bottom of the boat (using a 4' carpenter's level), the cavitation plate is about 3/4 inch above the plane of the bottom. As I continue to trim the motor down the leading edge of the cavitation plate approaches the top of the level and then ends up almost 1" below the top of the level when fully down. I almost never run with the motor fully down and with a Permatrim, that full down position would definitely drive the bow down into the water.

So the question is, with your motor trimmed to where the cavitation plate is parallel to the bottom of the boat, where is the cavitation plate in relation to the bottom? On the same plane, above the plane of the bottom, or below the plane of the bottom.

If I raised my motor any further, as the cavitation plate approaches a plane parallel to the bottom of the boat it would be in excess of 1 inch above the plane of the bottom. Besides that, I am not sure I am raise the motor any further as I am running out of transom. The top bolts are about 1.5 inches down from the top of the transom so I would be reluctant to raise them any.

[thataway]

Tom,
In your case, your Permatrim is already above the bottom of the boat when it is parallel to the bottom, so you would not raise it. The question is if you are getting any cavitation?

Driving the bow definatively down, is one of the goals of adding the Permatrim--this puts the "v" of the foreward lines of the boat into the chop, instead of the flatter bottom, aft. This is desirable only going into chop. Going down wind/chop/waves, putting the bow down can cause dangerous bow steering and a tendancy to broach. So down wind, you want the bow slightly up...

[breausaw]