# Cutting down a transom?



## MattR (Aug 27, 2017)

Hi everybody.

How many of you had to cut down a transom to accommodate a short shaft motor? The boat is a 1981 Smoker Craft Alaskan 14 footer and want to mount either my 1971 Johnson 20hp or 1950 something 18hp, both short shaft.

Thanks,
Matt


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## water bouy (Aug 28, 2017)

You might do a search on here for transoms. Also keep in mind the value of the boat once you customize it. Sometimes it goes up and sometimes it goes down. It might be easier and cheaper to trade a motor for a long shaft. Or find long shaft parts.


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## earl60446 (Aug 28, 2017)

Never had to cut one down although I would not do it on a boat I own. I would get a long shaft motor.
The peace of mind that 5 inches gives me is reassuring. 
Tim


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## DaleH (Aug 29, 2017)

Can it be done? Sure, but not what you want to hear ... as I wouldn't do it either. That hull is more valuable as a full height transom. Add an OB shaft extension or swap for a long shaft motor.


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## Stumpalump (Aug 29, 2017)

Seems like deals on great condition long shaft motors are a dime a dozen. Long shaft small tin boats are rare as hens teeth. Offer a trade on the boat or one of your outboards on Craigslist for a short transom or long shaft and I bet you come out way ahead. Another boat on here that I would love to have. Tall transom 14... Does it get better?


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## MattR (Aug 29, 2017)

I do appreciate that people took the time to reply/comment. With all due respect and not to be rude, yet I am guessing nobody that replied has ever tried to find a long shaft conversion kit for a 1971 Johnson 20hp before. NONE available in my area, and even if there was, the cost alone since they are tough to come by wouldn't justify converting it. Even if I would get lucky enough to find a conversion for the 20hp, I still want to use the 18hp at times on the boat. So now we are talking about finding another "needle in a haystack" conversion kit for that outboard. As far as finding a long shaft outboard 35hp "with tiller" or under is also out of the question since anything I could find was at least $1,000 minimum. Since I didn't win that $700 million powerball jackpot, I am forced to stay within my financial budget, which basically leaves me with one option, shortening the transom height. 

Which brings me to my original question is if anybody has done it and hoping to get any tips or hints regarding the project. I did try searching the forum regarding transoms, and it seems they all had the same responses as I received. I even thought of the option of a jackplate mounted upside down, yet I ruled that out since most say they cannot tilt the motor up then. The option of making an extension (to hang the motor off the back of the boat transom a bit) didn't seem like a viable option either since IMHO I believe that would cause more stress on the transom than shortening the transom itself would be, since that extension would have to be at least 10-12 inches long.

I will try to get some pics of the transom and get them uploaded today.


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## water bouy (Aug 29, 2017)

Not a big haystack.

https://www.ebay.com/itm/Johnson-Evinrude-25-HP-Long-Shaft-Extension-Kit-/253107654030

https://www.ebay.com/itm/vintage-johnson-evinrude-long-shaft-lower-unit-18-20-25-hp-foot-/253122186487


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## DaleH (Aug 29, 2017)

MattR said:


> Which brings me to my original question is if anybody has done it and hoping to get any tips or hints regarding the project.


Well, I did it ..._ sort of_, meaning that when I had replaced the ENTIRE transom of my current tin skiff ... it was far easier for me to make it into a full, tall transom piece and then cut it down to what I needed for the motor height (mine is a long shaft). But the process is the same. I actually raised the height of my transom (see red line in pictures) from where the old height was (blue line). I'd need to see a picture of your hull to get a good glimpse at the knee and other structural systems to give good input. 

I also cut it square and used bent channel aluminum cut on 45-degree angles, that was then bent and formed for the corners, for the trim cap. Internal to the cut (meaning where you can't see it) the 'cut' wasn't absolutely square - as there is a 1" radius corner. Truly square corners will be a form of stress riser - so avoid square cuts. I cut it with a sawzall and a new sharp blade. But drill the hole for the corner radiuses or radii (both are correct) in place 1st!

My new transom core isn't wood, but if your's is wood, I implore you to seal the exposed wood with epoxy. Buy the Sample Kit by Raka epoxy, only $18 before shipping (Link = *https://store.raka.com/epoxysamplekit.aspx*) and includes: _"This kit includes twelve ounces of our standard marine epoxy Resin 127 with fast 610 and slow 606 hardeners, a small sample of silica, micro-bubbles, and a sample of standard 6 oz. fiberglass. Price $18.00"_. That's enough premium marine epoxy product for you to do the job well, and more!

I bolted the aluminum channel trim cap on, but a good hardware store will sell ribbed aluminum nails that you could do it with too, as that is what many tin hull makers use. Seal any nails or fasteners with a good polysulfide caulk/sealant for marine use. *DO NOT* use regular silicone, as the curing agent in it attacks aluminum.

If using any SS hardware, insulate the SS from the aluminum by nylon washers under the washers for the nut or under the bolthead. Or use adhesive-lined heatshrink on the bolt body. I still recommend doing this, even if not used in saltwater, as aluminum is less noble than stainless steel and over time, the aluminum will corrode due to the presence of the SS, which steals its ions (called galvanic corrosion). A DIY cheap method - that works (I did it when I was poor ...) is to use duct tape. Yup, added a layer to backside of washers. It works!

So ... back to your original question of destroying [-X that fine tall-gunnelled hull (_am just kidding you here ..._ :wink: ) what else do you need to know?

Measure ... cut ... seal ... add trim cap. Mount motor and you're done! Strongly advise you measure 3 times and cut once.


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## MattR (Aug 29, 2017)

It looks like this project would be rather simple. I set the 18hp on the transom to get a visual idea of the available room.


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## MattR (Aug 29, 2017)

DaleH said:


> MattR said:
> 
> 
> > Which brings me to my original question is if anybody has done it and hoping to get any tips or hints regarding the project.
> ...



I knew the part regarding the corner radius and drilling holes for the corners, yet all the rest is knowledge I didn't have previously. My worst fear regarding the project was not that I might be reducing the boat's value by making it usable for my short shaft motors, it was doing the project the wrong way and having to rebuild it in a year or two. TYVM for the sound advice as it is greatly appreciated. I am hoping this is the last boat I buy. I did get a super sweet deal on it too. $200 for the boat and roller trailer.

water bouy... I noticed those the other day which is fine for the "newer" outboard that I have. Yet would still have to find something for the older 18hp. One of the main reasons I am shying away from the converting option is that in the area I am at, short shaft outboards are about half the price of a long shaft outboard. I always like having a spare outboard in the garage just in case one breaks down and while I am waiting on a parts order, I can still go fishing if I wanted to.


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## water bouy (Aug 29, 2017)

Nice boat. Is that another boat in the background. 
One reason I sold my 14 ft was the short transom and it had no splashwell. And the lakes I fish are not that big. Your splashwell may have to go too. For what you paid you could make a nice profit and buy one with a short transom. Mine had benches and it went for $1500 with only a trailer. Just spitballing.


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## MattR (Aug 29, 2017)

water bouy said:


> Nice boat. Is that another boat in the background.
> One reason I sold my 14 ft was the short transom and it had no splashwell. And the lakes I fish are not that big. Your splashwell may have to go too. For what you paid you could make a nice profit and buy one with a short transom. Mine had benches and it went for $1500 with only a trailer. Just spitballing.



Yes that is a 16 foot MirroCraft in the background. After I paid the guy for it, I was then informed he didn't have a title for it and had paperwork all filled out to send into the WI DNR to get a title for it. He "said" he would send it to me, but not holding my breath. If he follows through with what he claims, that is a plus. Paid $300 for that MirroCraft and it came with that old Johnson 18hp on it. Of course that is the boat that requires the short shaft outboard, yet I cannot use it legally because no title to register it. 

Right now boats are going cheap here in the central area of WI, unless it is a jon boat that can be used for duck hunting. Even if I waited until Spring to sell the SmokerCraft, to get $1,500 for it I would have to have an outboard mounted on it. 

If I do end up losing the splashwell, I am fine with that. I never back troll and almost always fishing in the shallows. I will have to be careful when letting off the throttle, yet I am used to that anyways since I always had boats for short shaft outboards.


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## muddywaders (Aug 30, 2017)

I like the open layout of your Smokercraft.You may regret cutting the transom down and it will devalue your boat.Best to find a longshaft parts motor with a good lower unit.Another option would be a bracket or pod which will move your weight balance aft and is better suited to remote steering.mw


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## LDUBS (Sep 1, 2017)

DaleH said:


> Strongly advise you measure 3 times and cut once.



I measured twice and cut three times and it was still too short! :LOL2:


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## MattR (Sep 1, 2017)

LDUBS said:


> DaleH said:
> 
> 
> > Strongly advise you measure 3 times and cut once.
> ...


When that happens LDUBS, I think you can just cut some from the bottom and add it to the top and it should be fine....lol.


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## stinkfoot (Sep 2, 2017)

Remember the boat that Seadoo made where you slot a SeaDoo in the hole to power it?
Get a pallet and mount your motor. Add a little flotation and you have a purpose built push-tug! Add a seat and you could rent it out! :LOL2:


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