I've decided to just build a longtail mud motor.
I've been doing a fair amount of reading, I also have a copy of the Mad Mud Motor plan's.
Some guy's like bearings throughout the shaft/housing assembly.
Some guy's say that bearing's are alright at the engine end, but not needed at the prop end, or in the middle.
I don't want to build more than one, I'd like to do it the best way, right from the start.
So, you guy's that run these motor's, have experience, I don't.
If you were building your own, or buying one, what kind of a shaft set-up would you be looking for?
Thanks
Jim

bushing at the prop end and middle some type of bearing assembly at the motor end.

Resurrecting this thread, lol. Is this still the case? It would seem to me that a sealed bearing on both ends with seals would be the way to go and add a bushing in the middle to get rid of the shaft "whip"

I understand that a shaft in 3/4" diameter needs to be supported every 42" max. unsupported length.

So I put a bushing about 24" from the prop end I use a bushing on the prop end as well. I lubricate the drive shaft top to bottom with synthetic gear lube, 70 - 90 weight. I use a wet sump do do this. I use high pressure wave lip seals top and bottom. My drive shaft is 17 - 4 stainless. It is a little harder. My seals polish a shallow grove at the wear point and the shaft seams to work harden and then doesn't wear further. Bearings - ball or roller are made out of carbon bearing steel and they eventually corrode out. I have taken my system apart with 5 -6 years on them and they are still in good shatpe. I put a my thrust collar at the top bearing on the driveshaft which is out of the water and moderately protected. Bear in mind that your driveshaft is turning 4,000 rpm and need a high speed lubricant or else a grease labrinth to make grease work with a bushing.

Every body has a theory. good luck!

Mark F. Cheney

I used an oilite bronze end bushing at the prop end and a regular bronze oilite bushing in the middle. And a pillow block style flange bearing at the motor side
This configuration is on a 22hp
It's simple. get a mud motor. shoot ducks in the face.

Oillite bushings top to bottom.
Lubricate with 90w gear oil.

Working good on over 20 units, mostly 6-7hp, some hunt 50+ days a year for the last 5 years and almost no signs of wear.
If your a commercial crawfisherman mechanical bearings my be better choice.