Prop shaft adapter?

[Speedo125]

The shaft on my boat is 1/8" dia. I want to move up to a larger prop. However, the larger props all seem to be bored for a 3/16" dia shaft. How can I fit that prop to my existing shaft? -Thom

[Brooks]

For a low power boat, nested K&S tubing might work. Build a bushing with the tubing, and clamp it tight to the shaft with a good setscrew in your prop and a new Allen wrench. I have used the tubing method with my vacutug, but it only took 1 layer. I am not sure how well your prop's setscrew will deform the multilayer tubing bushing. If you can remove the propshaft, you could silver solder the bushing to the shaft, file a flat, and then mount the prop the normal way.
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"Ole pro"...now I know I've arrived *grin*. Thanks for the compliment!

Heating the tubing red hot and letting it cool before installation will make it softer and more easily deformable. I did not need to do that with the 1 layer bushing, but it might help with the multilayer bushing. Vibration is a killer if you have a high speed prop, to be sure, so this K&S method would not be a good one in that case, I agree.

[retoabcr]

I do the same with mine with one exception. Now if i use carbon fiber prop only. The best way is to get a new 3/16" cable shaft from Octura and have it done with. The time you get a money order sent and it takes 8 calander days to your door, depending if you live in the USA. I have found out the hard way if using K & S tubing on a 1/8" for a 3/16" prop, vibration can easily occurr. Mr. Brooks is an ole pro, the way he decribes his method , he got it down to a gnats ( censored ). Now for certain cf prop, a 1/8" K & S slides over 1/8" cable shaft but you have to dremel disc to cut notches for the drive dog ears with 1/8" inside cf prop. CF prop have threads, so this method is needed.

[Ray Farina]

I had the same problem and I had found that SHIPS n' THINGS, INC. 41 North 10th Avenue, Manville, N.J. 08835-1513 sells 1/8' shaft with any length you need, and the shaft has a screw type end so you can put a nut on it to hold. I had the same problem with 2 boats that I was building, had the shaft and housing in them and found out that no one around makes a 2" diameter, 3 blade prop for 1/8" shaft. I had purchased many a year ago the last 2" nylon props that sterling had made and thought that I had both a left and right props, but found out that all of me props were all the same way. If you need further info come back to me at r.r.farina@att.net

[Speedo125]

Thanks guys. I appreciate your help.

I guess I should've mentioned that the props I need for my tug screw onto the end of the shaft. I think I'll take retroabcr's advice, bite the proverbial bullet, and invest in the new 3/16th shaft, the appropriate stuffing box and the larger prop that I need. -Thom

[toesup]

Thanks guys. I appreciate your help.

I guess I should've mentioned that the props I need for my tug screw onto the end of the shaft. I think I'll take retroabcr's advice, bite the proverbial bullet, and invest in the new 3/16th shaft, the appropriate stuffing box and the larger prop that I need. -Thom

I dont think an adapter is physically possible to go from 1/8 to 3/16, the threads would clash..
Although, just a thought, you might be able to drill out the 3/16 in the prop to 1/4" and then make an adapter to suit..