Prop swap

[claudia]

Could somebody please tell me if its possible to change a prop on a narrow boat while it is still in the water or is this a daft question cheers.

[stagedamager]

It's better out the water but possible to do in, if you really want to but I wouldn't!!!!

Dan

[BEngo]

Could somebody please tell me if its possible to change a prop on a narrow boat while it is still in the water or is this a daft question cheers.

 

 

It's relatively easy, provided you have a spare bit of prop-shaft and the water is deep enough to get the rudder out of the way. I posted how to do it somewhere on here, but I can't remember how to link to it- perhpas if you search my posts.

 

N

[carlt]

I did it with Usk's prop. It was surprisingly easy but I did get through 3 keys, trying to get it all back on (I bought 5, just in case).

 

I was expecting the nut to be impossible to get off but it was okay.

[Guest]

It's relatively easy, provided you have a spare bit of prop-shaft and the water is deep enough to get the rudder out of the way. I posted how to do it somewhere on here, but I can't remember how to link to it- perhpas if you search my posts.

 

N

 

As if by magic!!

[claudia]

Thank you all very much for your quick response. I am going to have a go how it goes is as you say in the lap of the gods. But at least I have a few good pointers cheers.

[churchward]

Could somebody please tell me if its possible to change a prop on a narrow boat while it is still in the water or is this a daft question cheers.

It is possible to do in the water but I think that would be in emergency only. You'd have to get wet! the possibility of dropping the vital nut and woodruff key in the cut is quite high!

[carlt]

It is possible to do in the water but I think that would be in emergency only. You'd have to get wet! the possibility of dropping the vital nut and woodruff key in the cut is quite high!

The keys are relatively cheap (though mine was a parallel key, not a Woodruff. I bought a few, from Midland Chandlers, and got a refund on the one I didn't lose (but I'm quite cak-handed).

 

I filled the socket up with plasticine, before knocking it onto the nut, to ensure a tight fit, so I didn't lose it.

 

I did it through the weed hatch, so I didn't get wet, above the elbows.

[stagedamager]

snip

I did it through the weed hatch, so I didn't get wet, above the elbows.

 

Aah, i forget some people, well most people have a weed hatch!!!!!

 

Regards,

 

Dan

[Chris Pink]

I've fitted a prop. in the water to a boat with no weedhatch which was actually easier than I thought it would be. There is, I believe, a picture of me doing so but in respect to the forum rules and guidelines I'll leave that to your imagination.

 

I am also much too mean to buy more than one key so it had to go in first time but was not a problem, I got the prop on, nearly to the point of covering the pin, put the keyway facing up and slid the prop over the key.

 

The tricky bit was lining up for the split pin, obviously it had to be drilled before going in - we did that by marking the shaft end so I had something to feel when it was in line. If I couldn't have done this I would imagine a castle nut would be essential.

 

 

eta: I was I remember, a little disappointed that we didn't get to do it in a lock on the cill (plan

Edited October 5, 2011 by Chris Pink

[carlt]

Aah, i forget some people, well most people have a weed hatch!!!!!

 

Not many people with a Josher (no rivets) have a weed hatch, though.

[David Mack]

I did it through the weed hatch, so I didn't get wet, above the elbows.

 

You had a weed hatch on Usk???

 

David

[blackrose]

Do you put a rope over the side of the boat and tie it around one of the blades before you start? I'm sure my prop won't fit through the weedhatch.

[claudia]

Thats a good point Blackrose!

[steelaway]

It is possible to do in the water but I think that would be in emergency only. You'd have to get wet! the possibility of dropping the vital nut and woodruff key in the cut is quite high!

 

I have done it three times.

If you are careful and get the key way at the top when you remove the prop you wont lose it

You may need to give the prop a sharp blow to knock it of its taper. I drive a wedge (mooring pin) between the prop and the hull

You can tighten it by jamming the spanner in the weed hatch and turning the gearbox coupling

The biggest problem is refitting the split pin, depending on the way it was originally fitted - I have had to make a 'castle nut' in the past.

 

Alex

[carlt]

You had a weed hatch on Usk???

 

Yes

 

Do you put a rope over the side of the boat and tie it around one of the blades before you start?

Yes I did.

 

Even if it fitted through the weed hatch I'd have still tied a line to it.

[claudia]

taking the comments about the woodruf key being at the top how do you know when it is at the top looking down through the hatch?

[bottle]

Now obviously those who have done it are right in saying it can be done in the water but..............................................

 

A friend had to have a new prop fitted and lets say that a few choice words were said in it's removal, a big hammer was needed and all this with the boat out of the water.

[bizzard]

Done this more than once.

Keep a magnet on a rope handy to retrieve dropped tools ect. Tie all tools looped to your wrist with bits of string. Tie rope to prop blade to retrieve old and to install new. If props stubborn to come off,Remove shaft u,j's or flexible coupling and bump it off, sliding propshaft backwards and forwards inside boat and so biffing the prop boss on tube boss.You may have to file key to fit the different prop.

Waters cold now.

[steelaway]

taking the comments about the woodruf key being at the top how do you know when it is at the top looking down through the hatch?

 

When the nut is off you can feel the key slot in the prop and the shaft, simply turn it the top. The key is about 10mm x 10mm x 50mm.

The key is only for locating the prop, the drive is taken by the taper fit onto the shaft

 

Remember that all these bits are brass and not magnetic.

 

Alex

[casper ghost]

I've taken a couple off while in dry dock. I can assure you it wouldn't have been easy while in the water as both were well jammed on. It took a 20 tonne hydraulic puller to remove one of them. The other still needed a puller and some heating to remove.

Casp'

[steelaway]

I've taken a couple off while in dry dock. I can assure you it wouldn't have been easy while in the water as both were well jammed on. It took a 20 tonne hydraulic puller to remove one of them. The other still needed a puller and some heating to remove.

Casp'

 

I've found with tapers that its sharp shock that breaks the taper more than simply pulling.

I once removed the fly wheel on an old Mini, I had Pickavant puller so tight that I couldn't turn it any more, I was so frustrated that I hit with the smallest of hammers - and it sprang onto my lap.

 

Alex

[claudia]

I was thinking would it be a good idea to run a sheet or tarp under the boat tied like a knotted hankerchief to catch anything that fell. I take the point that if its on tight there is no way I will shift it through the hatch, but I bet if I set off to the dry dock with the nut off it would fly off never to be seen again.

[bizzard]

I was thinking would it be a good idea to run a sheet or tarp under the boat tied like a knotted hankerchief to catch anything that fell. I take the point that if its on tight there is no way I will shift it through the hatch, but I bet if I set off to the dry dock with the nut off it would fly off never to be seen again.

In reverse it might.

A thick steel bar through the weed box and onto the side of prop boss and whack with club hammer,not too hard though,keep turning prop and do it on all sides in turn,make sure prop is close up to stern post first though.

To be honest the cold water might beat you, too cold now. Midsummers the time,nice and refreshing.

Edited October 6, 2011 by bizzard

[BEngo]

In reverse it might.

A thick steel bar through the weed box and onto the side of prop boss and whack with club hammer,not too hard though,keep turning prop and do it on all sides in turn,make sure prop is close up to stern post first though.

To be honest the cold water might beat you, too cold now. Midsummers the time,nice and refreshing.

 

 

Don't mess about down the weed hatch. Take the whole tail shaft with prop attached out and onto the bank where you can see what you are doing, catch what falls and have easy access for hammers etc.

 

Remember, as I was once told when still very green; "Don't force it lad, get a bigger 'ammer."

 

N