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I mounted a 12" Jack Plate on my 1979 22ft Revenge. The motor is a 2009 HO 200hp E-tec. The weight of the motor with the 12" extension has left a 3/8" bow over a 4 foot span. I have a 1/4" stainless plate on the interior of the transom that includes the bolts for the bracket.

I was contemplating a new aluminum plate that would spread the weight further, about 16" x 4 ft or, the same plate with a 4" x 6" aluminum channel welded on for stiffening. I know the plate by itself will spread the weight but would not be structural without the channel. I have yet to take off the motor to see if I can flex back the transom square.

Any ideas or knowledge of the structural would be appreciated. Is it something I should even be concerned with? The gel coat appears to be holding up but I have not done any trailering.

Garris

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I've had excellent results with "Sea Cast" check their web sight. Removing wood coring using their method is very labor intensive. On models that have a thicker transom in the engine mounting area (also where the wood is located), I've removed a section of the outer glass staying about 2 inches in from the edge of this area, then removed the wood, cleaned the surfaces, securely glassed the removed panel back in place, opened the top surface of the transom, fabricated a funnel, pouedr in the "Sea Cast" brining the level slightly above the top edge of the transom, once the "Sea Cast" is cured, shape the top of the transom for the proper contour (it's easy to work with) and height, and glass over the repaired area. This is also a good opportunity to remove any wet foam in the transom area and replace it with Sea Cast, order a little extra Sea Cast to make sure you have enough, they say you can add later, but I think it's best when used as one pour. The results are incredibly strong, and this stuff floats.

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I have a stainless steel plate covering all the 4 mounting holes and also folded 90 degrees on top of the transom. That helps stiffening. Also you can fold it forward 90 degreesat the bottom edge.
Make it as wide as possible to spread load from side to side of the transom.

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Thanks for the replies.

HR, I hope I caught this before structural repair. The bow in the transom seems to have become greater as I was doing work on the rest of the boat. I am hoping for an ounce of prevention is worth a pound of cure.

Petrus. I am in 100% agreement. My first option was the over transom stiffening. However, I have customized stainless rails that include the top of the transom that makes that detail prohibitive. I am planning to weld the aluminum channel a 1/2 " down from the top of the transom and spread the plate the maximum width before the transom curves start. I am leaving the 1/2" as a weldable area in case I need additional bar stock.

I am interested in others that installed Jack Plates for their boats. Is that 3/8" curvature over 4 feet standard or should I be concerned with structural integrity. Either way I am installing the larger plate, but is the channel necessary?

Garris

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I don't know much about the 22 Revenge but I've owned a few boats over the years and I have to say I would be very seriously concerned by that distortion of the transom while set boat is sitting still on dry land. Realistically transom a are built to be granite solid well in excess of the maximum recommended weight of the motor. Seems like that 12 inch jack plate is acting as a lever putting way more stress on the transom than it was designed for. Can't imagine what it would do to the boat while running in a chop. I would immediately remove the engine weight and get rid of the jack plate.

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Thanks Wing, my thoughts entirely. I just needed to know if movement with the jack plate standard. I have seen a lot of posts about the plate installation and wanted to know if I was an isolated incident or the norm.

Garris

Wing, I was hoping to offset the motor to put in a splash board to prevent flooding in the back of the boat. A Whaler drive would have been perfect, but I am committed pretty deep right now to make this work. I have seen innumerable posts about Jack Plates and high performance. I do not give a hoot about "hole shots". My transom is low and guests get wet feet when drift fishing. Quite frankly. I do not think I would ever want to go 45mph in a boat.

Garris

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I would agree with Wing.

Adding the weight of the jack plate and the motor 12" aft is added load to the transom and also causing the stern to sit even lower, exacerbating the wet feet.

I would want to know how the transom is with the motor mounted directly on the transom, does the "bow" disappear.

If you have to have the plate, I would either rebuild the transom or add significant reinforcement to the entire transom (corner to corner).

How about some photos?

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Phil,
I am "picture challenged" on the computer and the wife is out of town so cannot help me navigate. I believe both yours and Wings assessments are correct. Also my thoughts. I have never had the boat in the water with this setup so I cannot reply to "sitting lower". I had a 6 inch jack plate on in the past, but friends who have been in similarly hulled Whalers without the jack plate said wet feet common when drift fishing.

At this point I am looking for reinforcement for the flex. I know that each boat has different characteristics but, I read several posts and studied the different installations on this website, and thought that the jack plate installation was somewhat a "turn key". Others did it and I was hoping that the flex was standard. A little deflating not to hear what you want to hear. Maybe I do have to "can the experiment". Off to work and day dream a solution. I may have to go with additional bar stock to go the complete width of stern.

Thanks all so far for your comments, please keep them coming.

Garris

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Garris, I would be concerned. I would have it looked into.

HRBertram, Do you have pictures of your transom rebuild? Also, where are you located in MD?

Thanks, Don.

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The motor is off and I believe that the is a permanent bow in the transom. I set up a jack underneath the the jack plate and as it raised, the boat raised but, the transom stayed rigid. Looks like the 12" jack plate with the 200HO E-tec exaggerated the issue. The bow/curve is now subtle (closer to 3/16"). I also googled pictures of "Whalers with jack plates" and noticed some appeared to have a curve (tough to truly study, just angled photos, none directly overhead). No accompanying reference mentioned in write ups.

I removed the drain tube at the bottom of the transom and the wood is in excellent condition as well the wood for through holes for my trim tabs and electronics, etc.... . I consider this flex a by product of 35 years of a 600lb motor sitting on a transom the nature of an old boat. I do not consider it a problem enough to tear into the transom but it is enough of a concern to reinforce.

I just purchased 3/8" aluminum plate to cover the interior of the transom. The metal supplier had a remnant of 4" x 6" I beam which I am going to scribe and weld in place onto the top of the plate. Will span about 4' along the back. Plating over the transom would have been a cleaner look (thanks Petrus) but the curve made it too difficult to match. I am figuring that though bolting the plate will match the flex and then stiffen the top. In addition. I have some 1/2" aluminum plate which I am cutting to reinforce underneath the jack plate. It will attach to the transom, through bolted to the interior plate (I have an aversion to lag bolting) giving bottom support to the cantilever. I had several old time waterfront fishermen/boat repair folk take a look and say the subtle permanent flex no big deal and to reinforce as is. I will attempt to straighten once everything is off but any drastic measures might do more damage than good.

I am increasing the weight of the transom by about 115lb with the repair aluminum and jack plate. However, I moved my batteries and oil reservoir to the front of the boat. Any feedback would be nice. I have not started fabricating. One of the nice things is I now have an anchor winch and can easily put weight in the bow of the boat with additional chain. Thanks.

Garris

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Adding 115 lbs to the transom????? Plus the added weight of the jackplate assembly and the new heavy motor???? Do we think that will affect the attitude of the overall boat at rest in the water???? Do we think that the rear of the boat will sit considerably LOWER in the water than it did when people were "getting their feet wet" in the same boat before all this????? naaaah, it's probably going to be allright :)

I am going fishing, I'll get back to the drama here later :)

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Adding 100+ lbs to the transom. Never a good idea in my book.

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I have the same weight demons going through my head. When I referenced the weights of the new vs. old motor I believe the new repower was 35lb lighter. I am also going to modify my structural pieces to shed a couple of more lbs. .

What baffles me is that I have searched the web site about jack plates and no issues like this ever came up. Suddenly transom reinforcement at 60lb is an issue and quite possibly my boat hull was not meant for a 55lb. 12" jack plate. I have read the articles on extending the motor out. All pointed to a smoother, high performance, fuel saving option. I believe that if I decided to enclose the transom the weight issue would be a wash with my additional aluminum reinforcement. I just like the idea of keeping "self bailing" with a removable splash board.

Has anyone on this website added a jack plate to a 22ft 1979 to 1985 low cut transom whaler hull? Outrage or Revenge. If so, please please offer a comment. Thanks all and back to the drawing board. If all works out, might be a nice prototype. Worst thing to me is moving the motor back in, not that horrendous an option.

Garris

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I don't think the weight of the jack plate is the problem, it's the distance from the transom that you're mounting the motor. Boston Whaler didn't design that transom to sustain that kind of leverage. If you used a one pound jack plate that sat a 100 pound motor back a hundred feet it would probably break the transom off. I would get rid of the jack plate and mount the motor in the manner for which the boat was designed.

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I have a jackplate on my 18 Outrage, there was no flex or movement of the transom. It did sink the splashwelll drains under water if that is a concern to you as with the motor hung farther aft the attitude of the boat at rest and on plane is changed. If having wet feet is an issue, then hanging the engine off a jackplate will only make that worse not better. The jackplate does make the boat feel and handle like a larger boat, not sure how much more efficient or if you really do get better fuel economy. I did mine because I had installed a stern seat and I wanted the old smokey two stroke as far away from the people on the seat as possible. I left it on there when i repowered because i saw no reason to remove it.

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Wing, Galileo once said "...give me the moon as a fulcrum and a lever long enough, I can move the earth with my pinkie...". I am in complete agreement. I admit I am experimenting with this option and it may very well fail. I have also bid construction projects and lost more than the cost of my boat with improvements. I am taking the fulcrum and am displacing it throughout the transom and the stern. The bottom of my fulcrum would be 3" above the keel. I believe the closed transom/stern hulls displaces the weight (jack plate not mounted on top of transom but middle) more evenly and structurally. My bottom reinforcement is as integral as the top of the transom.

Kamie, thank you so much for your post. Like I always said, wet feet never bothered me. My goal is to have the motor completely outside of the stern. That allows the splash board over the back of the boat (closed transom). That 12" cantilever was a killer (leaves only 2" of clearance) and too much for the original design. That is why I never launched. I just want to drift fish without a wave or wake overwork the bilge for water removal. The hydraulic feature in the jack plate allows me motor adjustment (the pump and valve are in a cabinet in the front of the boat).

Quite honestly fellows, I have failed in experiments in the past. My goals are the advantages of a motor outside of the boat without the space taken up by a Whaler Drive or Armstrong Bracket (or similar). Honestly, I did not think what I was doing was so drastic or unconventional. I thought I would install the jack plate and motor into the sunset. My nickel. I will not launch without complete confidence.

Garris

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We have had this article on WhalerCentral since 2006.

I thought someone posted it here but it must have been another thread.
Keep it tight.
http://www.whalercentral.com/articles...icle_id=49

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Joe, thank you for the article reference. It was one of my guidelines (along with several other related articles) that I must have reread a dozen times before I started this endeavor. I will keep it tight.

Kamie, my splashwell drain is 12" below the existing water line. Does your hull have a couple drains higher up on the transom. If so, are they below that little barrier that separates the deck from the transom.

Silentpardner, well if all else fails I am now left with hydraulic steering.

"... to the Batmobile..."

Garris

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The 18 has three splashwell drains. Two are slightly above the deck but still below the barrier that separates the main deck from the splashwell. The third is in the center in a bilge area that is lower than the deck

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Kamie, Thanks for the information.
Garris

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I am having trouble following the logic here on several different levels. It is probably me.

Could someone tell me, please, how replacing a sea drive unit with a jackplate that was factory attached to an Outrage 18 full transom boat has any relevance at all, other than maybe the bolt pattern of a jackplate, to the project of adding a jackplate to 22' Revenge model that was factory equipped with a standard bolt on transom? I mean, the effective strength and buoyancy of a factory built closed transom, built for a sea drive at the factory, would seem almost certainly to be much greater than the 22' Revenge with a bolt on transom, or am I missing something here?

BTW, the fishing trip didn't go too well...managed to miss one good strike on a trolled Ballyhoo, had to return early. Sure hope I get another chance soon! Good Luck g, I feel your pain.

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In re-reading a few posts, I think we have gotten off track and muddled some specifications.

A jack plate is an appendage that allows the motor to be mounted to a plate that can be raised or lowered either by a mechanical device (screw) or by hydraulics.

A set back bracket is an appendage that allows a motor to be installed a set distance "back" behind the transom.

Using a set back bracket can exacerbate the tendency for a hull to squat (due to added weight) and/or porpoise while underway.

To reduce water over the transom of a hull, one could look at reducing the weight in the stern and/or installing splash door(s).

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Phil,
In essence, my reason for the set back was greediness. I wanted to increase my deck space as well as have "splash doors" at the stern of my boat. My "splash door" is a splash board is directly on top of my transom enclosing the rear of my boat. I needed the motor completely free of stern and the 12" jack plate was my solution.

I am glad Joe posted the article that I was familiar with. In retrospect I realize I took parts of different articles and applied them to my boat. None of which was a replica of my situation. With Joe's reminder, I am actually more optimistic now. If my current reinforcement does not work instead of canning the whole idea, I'll just enclose the stern completely and have what I was after all along. A boat ride with dry feet.

Garris

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Phil, as I understand this, gchuba is using a jackplate that is also set back from the transom 12". He is NOT using a 12" jackplate by itself.

Of course, there still hasn't been any pictures posted, confusion about this is certainly understandable :)

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Whether it is an 18', 20', 22', 25', etc., some type of bracket is needed if you want a "Full" transom.

Whaler basically had 2 types.
1. Sea Drive
2. Whaler Drive

A Sea Drive is basically the same thing as using a setback bracket or jack plate. The motor sits off the transom allowing a closed or full transom.

Finnegan ordered his 25' as a "Blank" sea drive and added his own bracket which was Armstrong or something similar I believe.
http://smg.photobucket.com/user/lgolt...amp;page=1
I don't remember why he just didn't purchase the Whaler Drive model but he had his own ideas.

I believe this is what gchuba is basically trying to accomplish.
A closed transom of some sort. Whether removable or permanent.

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As I understand it, a Sea Drive unit is most certainly not the same as a jackplate. A jackplate moves an engine vertically, and is normally attached directly to the transom. A Sea drive moves the engine back away from the transom of any boat, and does not move the engine up and down.

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Fellows, thanks all for the responses. Aside from research with the computer I am computer challenged for pictures and computer data transferring. My wife is with a new grandchild for another week plus and when she gets back will see about pictures/album.

Garris

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I think will all know that Silentpardner.
Basically the same as a Sea Drive unit however, in the way that the motor is setback off the transom like I said above.
It is a bracket no matter how you look at it.
1. Sea Drive
2. Whaler Drive (with flotation)
3. Jack Plate bracket (whether manual or hydraulic)
4. Setback bracket
5. Armstrong bracket (without flotation)

On a side note, I am not a fan of any brackets that do not provide flotation like the Whaler Drive.
Brackets can change the boat ride characteristics for the worse in some models.
Most of the time brackets are not needed unless the owner has a specific use and need for one.
I also think most brackets are ugly on a Whaler. But that is my personal opinion.