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Long shaft outboard on a short shaft transom?

4684 Views 15 Replies 12 Participants Last post by  ncgreg
Just wondering about possibly picking up a 20" shaft 4 stroke outboard to put on an older 14' sea nymph that takes a short shaft, in anticipation of later using this motor as a 2nd motor for a larger wider tiller steering boat down the road. Is this possible? The larger wider boat would probably be in the range of a 16' to 17' tiller steering boat. Thanks,
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It will work. You’ll lose a little bit of top end speed because there’s more stuff in the water causing drag. And you obviously won’t be able to operate in water as shallow as you should, but that’s the extent of the downsides.
Thanks. I suppose the alternative would be to get the short shaft and then put a bracket off the back when or if i get the wider boat. Are there any problems going that route?
It will work. You’ll lose a little bit of top end speed because there’s more stuff in the water causing drag. And you obviously won’t be able to operate in water as shallow as you should, but that’s the extent of the downsides.
It will throw more spray too.
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Lots of ways to skin a cat, but the simplest is usually the best.
You can run a short shaft now and get a long shaft kit down the road. Cheaper than new motor.
Just raise the transom
Thanks. I suppose the alternative would be to get the short shaft and then put a bracket off the back when or if i get the wider boat. Are there any problems going that route?
Just raise the transom
It will throw more spray too.
Both true. It will work, but throw a lot of spray up at the transom. With a tiller boat, you're gonna get a bath at cruising speed. If you rip a 2x4 in half and place it between the top of the transom and the outboard it will make a huge difference.
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Do it once and never have to redo it. Remove the cap over the transom now and glue up plywood to the same thickness of the transom. Then get some aluminum diamond plate and cut so it goes all the way across the rear of the boat and at least 2 or 3 inches so it overlaps the transon on the bottom. Use a good epoxy and glue the aluminum to the new transom piece. Once dry tap it into place and bolt it to the existing transom. I have done this on several boats I used for a while and sold. I told the new owner what I did and gave them the aluminum cap . I talked to one the other day and it still going strong. On that one I put a 3/4 inch thick cedar floor in it
Both true. It will work, but throw a lot of spray up at the transom. With a tiller boat, you're gonna get a bath at cruising speed. If you rip a 2x4 in half and place it between the top of the transom and the outboard it will make a huge difference.
I made one of those to. Bought wide aluminum angle and fired up the mill. I did not care for it so I sold it
I think your biggest problem maybe on a trailer. You may see that it sits low to the ground. So you may have to trailer it at an angle going down the road to prevent damage from bumps or approaches.
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How big of a motor are you putting on it?

Size does matter.

I do have a bracket that was bolted to a swim platform to hang a kicker on. Saved it from being tossed out. You might be able to modify it to work to extend the transom up for a small size motor. You are welcome to it.
I restored an old 1956 alumacraft and it didn't have enough transom for the new motors but this Panther bracker (depending on your HP) might help bring your motor up.
757455
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So this happened to me, the boat I had the past 5 seasons I bought not knowing it was a longshaft on a short shaft boat... Took it out the first time. I've never experienced so much water coming over the back, it was like Niagara Falls. No joke.

Went home called a few people did some googling and come up with asking myself "jackplate? What's that?". More Google and I went and bought one, at first I was trying to make one but I wanted to be able to adjust it on the fly if need be so I went and bought one. It was a good investment and worked well for shallow water running. Great addition to any duck boat or fishing boat. They are not cheap.
Tinboats.net web site has like 15 pages of jackplate info. Search “jackplate”, and good luck!
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