Removing a prop

[Alan Wheeler]

OK folks, I haven't removed a prop from a shaft myself. In a bit over a week, my boat comes out and I want to remove the prop and take it back to my workshop and polish it. So how do I remove it. I am presuming it is a Tappered shaft. Do I need a puller or just a block of wood and a very large hammer to give it a good wack.

Also, I want to check the rear bearing wear. At idle ingear, I get a little rumbly rattly sort of sound. Does anyone know what sort of max clearance is allowed between the shaft and bearing???

Thanks

[Vasco]

If you've got a wheel puller, that would be ideal although I have removed them with the wood and hammer method. First time I did it I was struggling and an old timer came up and gave it a helluva whack on the side with a block of wood and a hammer and it came off although I thought he nearly bent the shaft! No damage though. I prefer a wheel puller if one's available.

Beg, borrow, rent, jerry-rig, whatever you have to do to get a wheel puller!

Besides the possibility of bending the shaft, you also risk damage to the cutlass bearing, coupling, and transmissing bearings, not ot mention the prop itself. It's just not worth the risk, unless you planned on replacing all of those things anyway, which I doubt.

You'll likely here a bunch of people tell you that they use a hammer all the time, it's still not the best way. It's your boat, do it right!

[Gallivanters]

Alan,

I did the same job just two weeks ago and bought a spare set of bearings while I was at it for good measure. Hopefully I won't need the spares anytime soon... but I'm sure they'll cost more next time I need to change them. If you have a tough time finding new bearings now... go ahead and buy a spare set.

My rule of thumb has always been that if you can sense any movement between the shaft & bearing then it needs replacement. I generally replace the bearings every other haul out... or every four to six years when actively cruising.

After less than 50 hrs running time, I wasn't intending to to think too much about the bearings this time. However, upon inspection I was quite surprised to see that the slots in the inner rubber sleeve were gone and looked as if the bearing had been subjected to extreme heat. Knowing me... I must have snugged the packing nut prior to launch the last time I replaced them and prevented the shaft log from flooding which overheated the bearing and packing during the short voyage back to our berth. This time, I backed the nut completely off and allowed the log to fill with a copious ammount of water before stemming the flood. I let her settle a few days and then checked the shaft coupling allignment... which had shifted considerably.

Be gentle to your prop while removing it because, as stated above, you'll be shock-loading the transmission thrust bearings if trying to hammer it free. Better to buy, beg, borrow or fabricate a proper propeller puller. Try saying that fast three times in a row!

Good Luck,

Kirk

Definitely a puller. I have used a bit of heat from a propane torch with no ill effects as well. The shaft is tapered, and will have a key. It should also have a kotter pin. If the pin is not visible, but you can not see a hole, keep digging. You can end up destroying your threads from the remnants of a pin.

[soul searcher]

Leave one of the nuts on the shaft if you can some times when they come off they come off fast.

[Alan Wheeler]

Thanks guy's. A puller is no problem, if the one I have is big enough. I have a large Sykes Pikavant hydraulic puller with both 2 and three leg adaptors. So I would hope I can get it with that. But then, she is no girls blouse of a prop either. A decent lump of bronze sitting on a good 2" or so shaft.

[Jentine]

With the puller, you will need a five pound hammer. Back the nut off until 1/2 the threads are still on the shaft, tighten the puller as much as possible and when you can no longer tighten it, strike the puller screw. This should dislodge the prop from the shaft. Remove the puller, remove the nut and the prop is yours.

[Alan Wheeler]

Yeeaahh well you can't strike the puller screw on a hydraulic one. But that's OK, I'll give the prop a smack once I have all the tension on her.
So should I get Dawn to stand behind it in case it flies off with the instructions of, "it it drops, fall under it". I mean, I don't want to damage the prop now do I.

You do live dangerously don't you Don't over do it with the hydraulic puller. You can damage the prop, and/or the shaft with too much pressure. If things start to stretch, just put some heat to it, and it will come right off.

[hellosailor]

Wheels-
Before you hook up the puller...if you can...think about making a slush of dry ice and alcohol, loading it up in some old terry towel and wrapping it around the prop hub. Let it cold soak five or ten minutes and apply more slush "into" the hub as best you can.
Cold soaking parts that way often makes them contract differently and unstucks the part that is on the shaft, i.e. unstucks the prop.

I'd say to just pour on a thermos of liquid nitrogen but that cold soaks metals into confetti too often.<G>

[Alan Wheeler]

You'd do WHAT to Alcohol???? ;-)
Actually a little heat to Brass makes Brass expand like crazy. I often heat fit Brass parts at work.
I have also helped put a large bearing shell in to an earth mover hub using Liquid Nitro. The shell was over 6' in Diameter. We heated the hub and cooled the shell with the Nitrogen and then dropped the ring into the hub. Then smacked the snot out of it with a sledge hammer and block of wood till it was seated home. We had poured on about 20ltrs of Nitro. Cool floor show.

[Chrisc]

Alan,
Are you sure the rumbly rattly sound is your tail shaft bearing?
If you have a mechanical gear box it will produce exactly the sounds you describe when idling in gear if it is not fitted with a damper plate. I have a Twin Disc gear box and it does the same - increase the revs a little and the noise disappears as you load up the prop and thereby stop the backlash in the box. I am assured that this is not a problem.
It may not be your box, but just a thought.

Chris

[Alan Wheeler]

Yeah that's a good thought. Although my gearbox is a Velevet drive which is hydraulic, it still has a final drive gear system.
I ain't panicing yet, it's a simple check when the boat is hauled out in two days and the prop is coming off (hopefully) anyway.

[hellosailor]

Wheels-
"You'd do WHAT to Alcohol???? ;-) " Not the drinking kind.<G> In the states it is sometimes used to make a slurry with dry ice, which conducts the cold (so to speak) when you're trying to cold soak a part with dry ice as the source.

As you're familiar liquid nitro, then I'll rest assured you know how to freeze a shaft and smack it without turning it into glitter flakes. I've used a CO2 extinguisher so similar purposes, but most folks don't have a "spare" one to use for that, an they're up to about $25US for a refill now. OTOH, if you have one in the shop that is due for servicing....<G>....

Between detempering parts and setting toxin-painted vessels on fire...the torch just seems too adventurous to recommend at times.