Simple Prop Removal Tool

[yachtsmanbill]

That was made out of 10,000# steel flanges. Its never met a prop that it couldnt have for lunch (up to 2" shafts!). If you were really in a jam, you can put a hydraulic jack under the plate. Just tightening the nuts on the studs has always worked for me (?) !
FWIW... those studs should be simplex stud and NOT all-thred from the ace hardware. The 3/4" stuff has a tensile of about 25K lbs each. Thats 100,000lbs and a jack mite give up 20 tons.
These are from the shop... thats a 100 ton jack pulling a hub and a bearing with an 11" bore. These are usually heated to 275F which yields
.002" of expansion per inch of diameter. That makes the bearing .022 oversize hot, which cools to a .003" undersize fit. Banging on a bearing will Brinell where the rollers contact the races/cups. How much is too much? You be the judge. ws

[Mike36c]

I've used a prop knocker for years, no issues and they work great underwater too. I learned about them at a boatyard, they had several sizes and removed all their props with them.

[67hat34c]

I have a prop puller that I will want to sell. Will post info later.

[Beckytek]

I had my props removed last week for repair. The yard workers used a traditional wheel puller and tightened it as far as they could, then took a small sledge and hit the hub of my prop. Both times the prop banged loose. They didn't hit the end of the shaft or the end of the prop, but perpendicular to the plane of the shaft. Just one blow did the trick. Never saw that done before. Ron

[doc g]

I have removed alot of props underwater and that's always how I removed them ,bang on the hub rotate and bang again without using a puller . Gotta be sure to leave a nut on the end of the shaft though......don't ask me how I know that.............................Pat

[Genesis]

I have an "A-frame" puller - a big Mofo - that has never failed to get the wheel off.

You don't just tighten it until it pops though. You tighten it up then rap on the hub, tighten it a bit more, rap again, etc.

Keep the nut on loosely unless you like flying wheel!

I'd sell it but if I ever buy another big boat, I'll need it again. It was moderately expensive but worth every nickel - it works underwater too although you can't properly lap on re-installation underwater.

[Trojan]

I always use a puller. You tighten the puller by hand and if it does not break the prop free. I use a 10in piece of 1 1/4 hex bar stock, to get away from the blades and use a hammer on the side of the hub. The minuit amount of deformation of the hub will release the prop from the taper. You are never to use a hammer on the end of the shaft. Your only shafting your self.

BILL

[oldboat]

i got a little curious about this problem so i ran a simple analysis to see what force would be transmitted to the transmission end of the shaft when you hit the prop end with a hammer. the analysis was done as a non-linear problem with a time dependent solution. the force from the hammer was delivered to the shaft in the time shown on the time curve graph. the force goes from zero to 800lbf and then returns to zero in 0.05 seconds, the value of 800 lbf is just a guess. the second graph shows the reaction force on the transmission end. it is significantly lower than the input force, and shows more than one peak. the third picture shows the problem setup and resultant stress. it may not be that easy to read at this reduced resolution, but the stress on the shaft is insignificant. the shaft was held in place with two cutlass bearings that allowed the shaft to translate and rotate. the bearings were rubber but with only minimal friction. the shaft was fixed at the transmission end. the shaft was 316ss, 2 inch diameter, 15 feet long, and weighs 162 lbs. the prop was just a round bronze disk at 20 lbs. much too light but an ok starting point. if anyone knows the weight of a representative prop let me know and i will try to dial in the solution a little better.

[Brian Degulis]

That's to cool!! So your actually able to calculate the effect of the 800lb blow as it travels up the shaft? A 30x22 4 blade prop is about 80lbs so that's probably a pretty good average? How do you figure the force of the hammer blow? I remember reading somewhere that an average man with a long handle sledge striking down can generate a peak force of around 10,000 lbs is that bs?

Brian

[yachtsmanbill]

Hey Brian... look at the pic of the Hi-Torque loosening the bolts... a 16 lb sledge hammer didnt touch them! That unit generates generally about 30 tons (60K), depending on the drive head size. That one is a 1-1/4" drive. ws