help getting props off!

[kashurst]

been preping boat for big move on Monday. I am struggling to remove the props. They are 4 bladed nickel bronze on 50mm shafts. Spoke to yard mechanics who suggested a bronze drift and a very big hammer. Apparently heat wont work because if the coefficient of expansion of the props and shafts is too similar. I have put in a request for marina to get them off but I am generally not keen on hammering things to get them apart. Any tricks to try please?

 

[MYStargazer]

I've never has to, but this might work...
http://suffolkyacht.com/Propellors-and-shafts/how-to-remove-a-propellor.html

 

[burgundyben]

been preping boat for big move on Monday. I am struggling to remove the props. They are 4 bladed nickel bronze on 50mm shafts. Spoke to yard mechanics who suggested a bronze drift and a very big hammer. Apparently heat wont work because if the coefficient of expansion of the props and shafts is too similar. I have put in a request for marina to get them off but I am generally not keen on hammering things to get them apart. Any tricks to try please?

I have nickel aluminium bronze props on stainless shafts, get a puller on there, nip it up tight, heat the centre boss with a propane torch, they'll come off easy enough.

Keep tightening and heating until they come off, sometimes with a loud bang.

 

[volvopaul]

Hydraulic puller will do them cold, but heat will always help.

What kind of boatyard does not have a prop puller????

 

[aquapower]

I use a Sykes hydraulic puller, dont fully remove the nut as when it comes off it will hurt if you are in the way, if fitted with a dome nut then tie to P bracket with rope, put on the tension then if required give the hub a tap using a drift.

 

[DAKA]

Hydraulic puller will do them cold, but heat will always help.

What kind of boatyard does not have a prop puller????

I have to say Volvopaul is giving some excellent advice here, the boat yard in my old marina didnt appear to have one for a 4 bladed prop and made a real pigs ear of it which cost me real money to rectify, you might want to think about appointing someone else.[/QUOTE]

I had the same trouble with mine about 5 years ago.
The so called professionals made a right mess of them and they had to be reworked by Hamble props.
They used a drift among other things and a few months later I found an oil leak from my hydraulic gearbox which I replaced, cant prove it was from the drift but the gearbox only had a few hours on it and are usually bombproof.

I didnt try it but Fisherman of this parish suggested 'ringing'.

Use two hammers to hit the hub which causes vibration and the prop pops off.
One hammer is held against one side while the other hits the side of the hub.

Others suggest hitting the end of the shaft , and others place a acme harmonic block on the prop nut to welt the shaft , all these methods are putting vibrations into the prop which is the most gentle way to remove.
Perhaps send a pm to fisherman to ask for full details in case I have remembered it wrong after 5 years.

 

[David_J]

I use a Sykes hydraulic puller, dont fully remove the nut as when it comes off it will hurt if you are in the way, if fitted with a dome nut then tie to P bracket with rope, put on the tension then if required give the hub a tap using a drift.

I agree a puller is the only way and there can be a real bang when the taper releases but the prop does not actually fly off, it snaps free of the taper and can then fall on the floor causing damage if not restrained in some way. I am sure a lot of people using a puller on something the size of a prop leave the nut on the end of the shaft due to fear of the prop flying off at great speed!!! Be carefull however if you use a mechanical puller as the action of tightening the puller screw onto the prop nut can damage the threads if the pressure is onto the nut and not onto the shaft. This is certainly the case if the prop nut design has threads on the end for securing a prop anode. Even if the damaged threads are recut they are never the same and there is a real risk the prop anode will fall off. Use a puller and an old nut. Tighten the puller and give the prop hub a sharp tap. Repeat if needed!

 

[aquapower]

I agree a puller is the only way and there can be a real bang when the taper releases but the prop does not actually fly off, it snaps free of the taper and can then fall on the floor causing damage if not restrained in some way. I am sure a lot of people using a puller on something the size of a prop leave the nut on the end of the shaft due to fear of the prop flying off at great speed!!! Be carefull however if you use a mechanical puller as the action of tightening the puller screw onto the prop nut can damage the threads if the pressure is onto the nut and not onto the shaft. This is certainly the case if the prop nut design has threads on the end for securing a prop anode. Even if the damaged threads are recut they are never the same and there is a real risk the prop anode will fall off. Use a puller and an old nut. Tighten the puller and give the prop hub a sharp tap. Repeat if needed!

Yes I agree, and would never put any tension on the nut, reson for the rope was so dome nut can be removed and rope will stop prop from comming right off, the Sykes puller has a proper end that will only press on the middle of the shaft.

 

[kashurst]

props now off OK

thanks for all the advice. I made a DIY prop puller and they came off exactly as described. one without any heat, the other a good warm up and a sharp blow on the hub with a hammer.
further question please - when they go back on should I lightly grease the taper first with water proof grease or just put them on dry????

 

[Shibumi]

thanks for all the advice. I made a DIY prop puller and they came off exactly as described. one without any heat, the other a good warm up and a sharp blow on the hub with a hammer.
further question please - when they go back on should I lightly grease the taper first with water proof grease or just put them on dry????

Dry - it is the friction on the taper that does the work.

Incidentally, totally ignore the 'bronze drift' advice - it's dangerous. Brass or bronze drifts can splinter - not good.

In my personal experience, I have never seen the puller and heat method fail, it always works eventually, even with props in excess of 20 tons weight.

 

[Ripster]

When I asked for the yard to take mine off (bronze 4 blade), the guy came with the heat torch, heated up the hubs for about 20 secs and they just slid off with a small tap from a soft hammer. No need for a puller or any hammering. Just remember to leave the nuts loose on or the props end up on the floor!

 

[Neil_Y]

We advise jacking the props off.

More control, less chance of damaging hub with puller hooks or puller hooks coming off hub and works with our rope cutter spool.

All you need is a rigid box section steel tube, with holes to take two studs and a nut welded in the centre to take another threaded bar/bolt that will push against the shaft centre.

Drill and tap two holes in prop hub from rear opposite each other, thread two threaded rods into these, place the box section bare across the studs and thread bolt into centre until it pulls off prop (with some heat if needed)

 

[Brittany]

I struggled for ages to get a large prop off a 4" shaft with pullers, heat etc; eventually had to draw the whole shaft and took the lot to a prop re-furbishing company. Imagine my feelings when they just took a bronze lump hammer and thwacked the prop on the side of the main body between the blades a few times and off it popped. The guy said it worked every time as the vibration interrupted the friction seal to the shaft.