What is the correct size transom???

I have a 16' Alumicraft modified-V with a Beavertail 27hp long tail mud motor. It has a 21'' Transom and I was told for the long tail to work efficiently I should have a 16'' Transom. Is this true will the 5'' make a difference in the transom performance change???? Also has anyone seen a alumicraft 16' with a16'' transom? Can I have my transom cut down and still be safe to operate?

Please give any advice!!!

From what ive heard on here longtails work better on short transom boats. i have never ran one on a tall transom boat. but have ran them on short transom boat so i do not know the difference.

You need to match the transom height for the motor. You will probably have a hard time keeping the prop under the water if you put it on like it is. You can half-ass correct this by bending the cavitation plate, but you are better off set up right to start with. You can have your transom cut down and be fine, it won't hurt your boat's strength if its done right. Call beavertail and see if they make a drop mount before you go cutting your boat, 20 inch transoms are safer and get less backwash when you stop.

Go with the 16" if possible.

Thanks, You are exactly right in your description, It is very difficult maintaining the prop beneath the surface while at full speed. Its raises in and out; and it is terrible to do any turning. I was hoping the height was the issue rather than the hardship of using a mud motor.

Also, I have two large performance pods that can be added to the transom. If I do cut down the height of the transom and add these pods would the height be raised to high again? Is there any real benefit to the pods?

John

you dont need the pods unless you boat is saggin low in the water.

I pretty much have the same story, here is what I posted to tinboats:

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I have a Alumacraft MV 1648 NCS w/ tall transom and am about to take delivery of a 27HP beavertail longtail. There are no options for shaft length to accommodate a taller transom from BT so I'm wondering if anyone out here has any advice to me.

I think I have a couple of options maybe:

1) Drop plate?
2) Cut the transom down - would I still be able to swing the motor into the boat if I cut it down to 16"?
3) Find a different motor/boat combo

How much would I expect to be charged at a shop for the transom work? I'd do it myself but I don't have the skills to make a new cap for it since the old one wouldn't fit anymore.

What is the best type of shop to get this work done at? Custom fab place or a boat place?

I also live in MN so any local advice on a shop would be appreciated.

To answer your question about whats different with the motors......the standard shaft is 72 inches long, and the high transom model is like 84 inches long.

I tried a 72" shaft on a tall transom boat before. Not fun at all. They are not suppose to be that difficult to run.

I just talked to Beavertail (ottersports) and the guy there said that the 27hp kohler longtail will run fine on a 20" transom, you just need to make an adjustment using some 9" bolt.

He also said that since these guys took over Beavertail they changed the motor, and that the older ones didn't have this option. How old is your motor?

16" transom is correct... I run that exact motor.

I run a LT on my tall transom Aucoin boat. I did have to re work the cavitation plate on the motor to get it to run right in the water. It was no problem at all to do. I am extremely happy with it and the way it drives and turns. My motor was originally for a 16'' transom which is 72'' shaft I think. Again no complaints once I got the cavitation plate right!

@JpEater: I just got my boat in the water with my beavertail LT 27hp kohler today for the maiden voyage. I couldn't get it to stay in the water even at half power. I plan on bending the cavitation plate up tomorrow and trying again, hopefully this solves my problem. What size boat do you run btw?

im the same way my boatis 15 inch transome i just bent the plate right and got a long stud instead of the bolt in it originally and it worked great after that

15" transom?? why did you bend it? it's supposed to fit on a 15" isn't it?

you tell this crazy motor that it has a mind of its own i tried flat it wanted to pop up i tried up just a little bit again went up now i got it bent right i drive long distances with my hips instead of my hands just stand there and let the motor push against you and take off

lol thats funny

For a tall transom you have to cut the cavitation plate off and reweld it at a different angle. Shaft length has nothing to do with it. You can bend the plate as it is on their but bending it may not and won't be enough. You can add to it, but that looks like shit. It only takes about 45 min to do it right.

How do you know what angle to mount it at?

I have the same problem.

I have a motor made for short transom on my tall transom.

Do I bend the cavitation plate up or down?

The easiest fix is to cut the transom...sorry, but true. My friend suffered for several seasons with a high transom and the same issues and finally cut it down. Hey, you will still have 3/4 of high transom to fend off backwash if need be. Actually, I've driven short transom boats for years and you learn quickly how to avoid it. Believe me, you don't want an 84" LT! The newer BackH2O line of LT's are more "high transom" friendly, with more adjustment points, but since you have the BT might as well cut the sucker.
JpEater, is that 1848 Aucoin hull a short transom? I am moving in that direction with hopefully a 35 HP LT! What does that puppy weigh? If you see the other thread, I am looking for the lightest 18' hull possible for that scenario- we don't have much mud, cypress knees, beaver dams, and the like so I'd do with a .100 skin. I'm a fit 61, but I don't need any hernias! Sorry for the hijack, Newtomudmotors!