Fitting a prop while in the water?

[TandC]

I can't imagine it's sensible...  but would it be possible to fit a propeller to the shaft with the boat still in the water (shallows, marina, etc) .... standing in the water...  maybe with a snorkel!?

 

What's involved?  is there a keyway on the prop shaft?  Something super-fiddly that you just wouldn't be able to achieve without scuba gear? 

 

 

 

 

Where's Bizzard to come up with a DIY diving bell? 

 

 

[Tonka]

9 minutes ago, TandC said:

I can't imagine it's sensible...  but would it be possible to fit a propeller to the shaft with the boat still in the water (shallows, marina, etc) .... standing in the water...  maybe with a snorkel!?

 

What's involved?  is there a keyway on the prop shaft?  Something super-fiddly that you just wouldn't be able to achieve without scuba gear? 

 

 

 

 

Where's Bizzard to come up with a DIY diving bell? 

 

 

Is there not a slipway nearby where you can drag the stern up enough to do it. Mike Heywood did our 50ft prop and shaft like that at Hoo Mill.

Or are you near a tidal river to do it when the tide is out

[nicknorman]

Yes it is possible. But difficult and fiddly! There is usually a nut with split pin, the prop is on a tapered shaft (so might not come off easily) and there is a key and keyways.

[Tony Brooks]

2 minutes ago, nicknorman said:

so might not come off easily

 

I think that in the majority of cases that is a massive understatement. In the past I have had to use a combination of puller, heat and hitting the side of the boss with a large hammer to shift props. I have never had one that pulled off by hand. If you are lucky, just hitting the side of the boss may shock it off, but underwater!

[Jen-in-Wellies]

A neighbour did it. Removed the rudder, then removed the prop and propshaft as a unit and very quickly shoved a tapered wooden bung in the hole, via the weed hatch. Remarkably little water came in. Has the advantage that the prop can be swapped  out of the water. Not for the faint hearted and a good idea to have a working bilge pump, or two.

[David Mack]

And if you drop the key/nut/washer/split pin?

1 minute ago, Jen-in-Wellies said:

A neighbour did it. Removed the rudder, then removed the prop and propshaft as a unit and very quickly shoved a tapered wooden bung in the hole, via the weed hatch. Remarkably little water came in. Has the advantage that the prop can be swapped  out of the water. Not for the faint hearted and a good idea to have a working bilge pump, or two.

Getting the propshaft out and a tapered wooden bung in might be quick. But I think it might take rather longer to take the wooden bung out then get the (non-tapered) shaft back into the stern tube.

[PaulJ]

If new and old props are exactly the same you may manage it. Going to be very hard to check if the prop is sitting on the taper properly- the keyways on both props may vary.

Boss/hub length may also be slightly (had less slightly too) different so both were it actually fits and the split pin is unlikely to be in the right place either. 

Not impossible but so much harder. 

[davidg]

Depends on how the stern tube is arranged but I’ve done this on a Grand Union boat.

Remove rudder

Make a piece of plywood drilled to take the stuffing box studs.

Undo tail shaft coupling, remove any keys, pins etc. from shaft

Tie a rope round the shaft inboard of the  blade

Grease one face of the plywood

Push the shaft back with someone holding the rope but not all the way out

When the inboard end of the tail shaft is clear of the inboard end of the stern tube remove the stuffing box packer

Put the plywood on the studs greased face towards the stern tube and hold it on with the stuffing box nuts

Pull the shaft the rest of the way out

 

Very little water comes in

 

To reassemble reverse the removal procedure. 😀 With a weed hatch getting the end of the shaft back in is easy, without a weed hatch less so.

 

 

 

[BEngo]

2 hours ago, David Mack said:

And if you drop the key/nut/washer/split pin?

Getting the propshaft out and a tapered wooden bung in might be quick. But I think it might take rather longer to take the wooden bung out then get the (non-tapered) shaft back into the stern tube.

You dont have to do that. 

 

The technique is to put the bung in from inside when removing the shaft.   Ypu can use it to push the ( firmly tied on) prop shaft back. Then, when refitting push the bung inwards with the shaft, having eased the gland follower nuts.  Very little water comes in if the stern bearing is on good order.

 

I used a  short piece of spare tail shaft as the bung.  Once the prop was away a couple of ty-wraps either end were added to stop the bung coming out.

N

[MtB]

3 hours ago, TandC said:

I can't imagine it's sensible...  but would it be possible to fit a propeller to the shaft with the boat still in the water (shallows, marina, etc) .... standing in the water...  maybe with a snorkel!?

 

I'd have thought this was perfectly possible through the weed hatch. If awkward and time-consuming. 

 

Removing the old prop if there is one already on the shaft however, a different story! 

 

Mind you we do hear tales of props falling off when astern is engaged if the nut has fallen orf, so they aren't always firmly engaged on the taper. 

 

 

[peterboat]

I did mine on the widebeam through the weedhatch had to use a puller on it to remove very fiddly indeed but doable

[ditchcrawler]

@Biggles did it through his weed hatch

[Biggles]

I did. It took about 4 hours through the weed hatch. Make sure all tools used are tied onto something. And be ready to collect anything that can fall off. Because it will!

 

I changed again on dry land and it took about an hour. 

[Ex Brummie]

I saw an old hand who having removed the rudder, withdrew the prop and shaft and used a pound of lard to seal the stern tube. Certainly not for the faint hearted, but he maintained it was often the way on old working boats.

[blackrose]

I had my boat pulled up a slipway stern first to get the prop off with the bow still in the water. I stood at the bow doors while they pulled it up and the river water came through the well deck scuppers and stopped a couple of inches short of the bottom of the doors. Heart in mouth moment. It would have made a nasty mess. 

 

Then I realised the little swan neck water tank vent was underwater.

47 minutes ago, Ex Brummie said:

I saw an old hand who having removed the rudder, withdrew the prop and shaft and used a pound of lard to seal the stern tube. Certainly not for the faint hearted, but he maintained it was often the way on old working boats.

 

Lard? I heard they used to use a pound of tripe. It sounds like a load of old working boat bollox to me. 

 

These days I think you'd be better off using something like plasticine or modelling clay.

[robtheplod]

I wouldn't have the confidence to do this in the water or on a tide.... something will always go wrong.....

[ditchcrawler]

50 minutes ago, blackrose said:

I had my boat pulled up a slipway stern first to get the prop off with the bow still in the water. I stood at the bow doors while they pulled it up and the river water came through the well deck scuppers and stopped a couple of inches short of the bottom of the doors. Heart in mouth moment. It would have made a nasty mess. 

 

Then I realised the little swan neck water tank vent was underwater.

 

Lard? I heard they used to use a pound of tripe. It sounds like a load of old working boat bollox to me. 

 

These days I think you'd be better off using something like plasticine or modelling clay.

Tripe would be no good, but the fat you get when you boil it up would be OK 

[blackrose]

39 minutes ago, robtheplod said:

I wouldn't have the confidence to do this in the water or on a tide.... something will always go wrong.....

 

I've beached my boat on a tideway before just to have a look at some rust patches, but like you I wouldn't do something where I was under time pressure to fix something or risk sinking. Too much stress.

13 minutes ago, ditchcrawler said:

Tripe would be no good, but the fat you get when you boil it up would be OK 

 

The old working boatmen used boiled tripe with onions - and gravy! 

[nb Innisfree]

I once changed the prop through the weed hatch, water temp was below freezing & the pain was unbelievable, faded away after 15 mins but that is the point at which physical damage starts to occur, had to withdraw and warm up (more pain) then start again, not recommended in winter! 🥶

[magnetman]

10 minutes ago, nb Innisfree said:

I once changed the prop through the weed hatch,

Out of interest what circumstance led to you needing to change the propeller? 

 

 

[ditchcrawler]

1 hour ago, blackrose said:

The old working boatmen used boiled tripe with onions - and gravy! 

Yes but that wasn't fresh tripe, That is where the fat comes from. They use to sell tripe on Gt Yarmouth market. The fresh tripe was boiled and cleaned down some old buildings that many years ago were the old slaughter houses. The fat or lard that came off was used to fry the market chips in. This was in 1980 and before, today its all "healthy" processed oil to fry in.

[nb Innisfree]

2 hours ago, magnetman said:

Out of interest what circumstance led to you needing to change the propeller? 

 

 

Change of 2k rpm engine to 3k rpm one, same prop actually just had it reworked by Crowthers.

 

Crowthers RIP 

Edited March 26 by nb Innisfree

[magnetman]

Yes it is a shame that Crowthers closed down. They were brilliant. 

[peterboat]

1 hour ago, magnetman said:

Yes it is a shame that Crowthers closed down. They were brilliant. 

We have Woodwards up north they produce very large propellers as well as repairing or modifying them

[MtB]

1 hour ago, magnetman said:

Yes it is a shame that Crowthers closed down. They were brilliant. 

 

And too cheap, presumably.