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I'm currently in the process of buying a boat (ūüėĀ). The vendor recently commissioned a survey and the boat is very evidently in very good condition, so I don't feel the need to commission my own survey¬†and thus the boat doesn't need to come out of the water. The blacking is in good condition too and won't need redoing for a while.

 

Except that one of the few things the survey did pick up on, and the only thing that'd require it to come out of the water to be rectified, is that the prop is loose and is able to rotate about 5 degrees in either direction around the taper. I don't have any experience of loose props or any real knowledge of why it might be loose, and it'd be much more convenient if fixing it could be deferred - if not until the boat next needs to come out of the water (next winter at the earliest), then at least a few months - June would be ideal. Is it something that likely needs immediate attention, or is it something that might be able to wait a while? Obviously if it needs to come out it needs to come out, I have no problem with that, just wondering if it's the sort of thing that could wait until a more convenient time?

 

My range over the next six months won't be more tha 100 miles or so, all on canals. Obviously I won't be going anywhere near rivers while there are any questions or doubts.

 

(If you're wondering why it's my problem rather than a useful bargaining chip - I struck what I think is a very good deal for the hassle of dealing with the survey recommendations myself, and it was reflected in the price).

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Others with more experience than me will be along in due course but a loose prop would worry me. If it’s already rattling against the key how much more can the key take before it gives up completely?  The key is only a belt and braces thing anyway; the prop should be tightly locked on the taper. I wonder if it’s not matched to the shaft?

 

Thats all quite apart from ignoring the usual wisdom of never relying on a vendor’s survey. 
 

 

Edited by WotEver
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9 minutes ago, tehmarks said:

I'm currently in the process of buying a boat (ūüėĀ). The vendor recently commissioned a survey and the boat is very evidently in very good condition, so I don't feel the need to commission my own survey

Hopefully you didn't buy it from a broker near Daventry who have a history of 'mates writing surveys' without having even looked at the boat.

 

Irrespective, if the survey did not notice something that you subsequently find then you have no (absolutely none) come back on the surveyor as the 'contract' was not between you and the surveyor.

NEVER buy a boat whilst relying on a survey not conducted by YOUR surveyor.

 

Replacement of a loose / worn prop or shaft could well cost more than hiring a surveyor.

 

 

Its not too late - cancel the agreement and start again.

 

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A loose prop is serious and should have been fixed when it was out of the water.  The prop moving around on the shaft it going to do damage to the prop and/or the shaft if it hasn't already.  Replacing a prop and or shaft wouldn't be cheap. Wait long enough you will have to do both and if it fails you have going to have to be towed.

I would be concerned as that could be an expensive repair that needs to be done now. If you ignore it it will be an expensive repair.  I am bettin the cost is why I wasn't addressed while it was out.
Totally agree with what ALan said too.

Edited by Kudzucraft
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16 minutes ago, Alan de Enfield said:

Hopefully you didn't buy it from a broker near Daventry who have a history of 'mates writing surveys' without having even looked at the boat.

 

Irrespective, if the survey did not notice something that you subsequently find then you have no (absolutely none) come back on the surveyor as the 'contract' was not between you and the surveyor.

NEVER buy a boat whilst relying on a survey not conducted by YOUR surveyor.

 

Replacement of a loose / worn prop or shaft could well cost more than hiring a surveyor.

 

 

Its not too late - cancel the agreement and start again.

 

Not that particular broker, no. I don't consider that I'm relying on the survey; it was good confirmation of the impression I got with my own eyes while poking around the bits you might expect to be rusty, damp or dodgy, and I'm happy with the risk I'm taking on by not having a survey carried out myself. And when I sink in three months time, you can tell me you told me so!

15 minutes ago, Kudzucraft said:

I would be concerned as that could be an expensive repair that needs to be done now. If you ignore it it will be an expensive repair.  I am bettin the cost is why I wasn't addressed while it was out.

That's all the information I need. You are right, I'm certain the cost is the reason it wasn't addressed while it was out of the water, but I'm also confident it'll cost less to resolve than what I've negotiated off the asking price. And I think the original asking price was otherwise very fair - so I'm happy. Out of the water it will come.

:)

Edited by tehmarks
Typo correction

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1 minute ago, tehmarks said:

Not that particular broker, no. I don't consider that I'm relying on the survey; it was good confirmation of the impression I got with my own eyes while poking around the bits you might expect to be rusty, damp or dodgy, and I'm happy with the risk I'm taking on by not having a survy carried out myself. And when I sink in three months time, you can tell me you told me so!

That's all the information I need. You are right, I'm certain the cost is the reason it wasn't addressed while it was out of the water, but I'm also confident it'll cost less to resolve than what I've negotiated off the asking price. And I think the original asking price was otherwise very fair - so I'm happy. Out of the water it will come.

:)

As long as you are acting in the knowledge of the likely impact of the fault, then I hope it all goes OK for you. Good luck.

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If the prop has come loose that may well be because the nut that holds it onto the taper on the propshaft has come loose. In which case there is every possibility that the nut will unscrew completely, and the next time you put the boat into reverse, the prop will spin off backwards. And then you will have no propulsion, forwards or backwards.

I would suggest you should open the weedhatch and reach down and find the nut to see if it is still there and if its loose.

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The question I would ask the surveyor is why is it loose?  Presumably if it was something as simple as a loose nut it would have been tightened at the survey.

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A loose propeller will be acting like an unbalanced one.  It may have damaged the shaft as well as the tube.

If it's moving five degrees around the taper I'd suggest it has already damaged the key which may already have had a detrimental effect on the taper.

 

It's impossible to say how long it's going to hang on, it might be 100 yards - 100 miles - 100 years, however the longer it's left the more expensive it's going to be.

Your approach to accepting someone else's survey, especially in the light of how they've allowed something as major as a loose prop to go unattended, I find optimistic.

 

I get the feeling you've made your mind up what you're going to do and are looking for agreement.

Still the things that stop us from sleeping at night are all different, best of luck I hope it goes well for you.

 

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5 minutes ago, zenataomm said:

I get the feeling you've made your mind up what you're going to do and are looking for agreement.

Still the things that stop us from sleeping at night are all different, best of luck I hope it goes well for you.

 

I've made my mind up what I'm going to do (buy the boat), and I'm looking for informed opinion on something I don't really have the knowledge to form an opinion on (how urgently a loose prop will need looking at). The opinion is clearly that it needs looking at urgently, so that is what I'll do.

 

What I do have is a rough idea of what it could cost me, and I'm perfectly happy with that.

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As a ballpark, a new prop = 500-800, stern gear + shaft 1500 +, docking 300. Very likely this will be the starting point. If this has been run in that condition for some time the vibration could have affected coupling, drive plate, etc.

 The vague nature of the defect is a worry in itself. 

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If the previous owner put it back in the water knowing the prop was loose, what other problems / lack of maintenance has been ignored? It just indicates a mind-set of the previous owner, and not a good one.

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I am unsure why the OP is asking about the loose prop. If it is loose, it should be corrected as part of the sale agreement. When we sold Helvetia, the surveyor identified a couple of minor issues with the boiler flue, which were not imminently dangerous, but neverthe less desirable to get rectified. We got a quote from a reliable engineer and agreed to pay for the repairs as part of the sale agreement. I thought that was what any reasonable person would do, and if the vendor is unwilling to get the prop fixed, I would consider walking away.

 

 

Edited by David Schweizer

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That much movement would suggest that the key has fretted the key slot in the propellor at the very least and damaged the tapers too. It is just possible that the propellor shaft being a steel alloy may have survived and the softer bronze of the propellor is the part that has taken the beating.

 

If the taper in the prop and on the shaft have survived or can be cleaned up then the cheapest option is to have the keyways in the prop and shaft enlarged and a new key made to fit. Depending on the facilities to hand in your chosen machineshop then the propellor might need rebalancing.

 

Either way it is going to cost but should not be delayed.

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1 hour ago, tehmarks said:

I've made my mind up what I'm going to do (buy the boat), and I'm looking for informed opinion on something I don't really have the knowledge to form an opinion on (how urgently a loose prop will need looking at). The opinion is clearly that it needs looking at urgently, so that is what I'll do.

 

What I do have is a rough idea of what it could cost me, and I'm perfectly happy with that.

 

The important point is, if the loose prop was an easy fix it would have been fixed while the boat was out of the water rather than have it noted as a fault on the survey. 

 

Therefore we can surmise it is a difficult fix. There is probably something fundamentally wrong preventing the prop being tightened so chances are, the prop and the prop shaft both need replacing, and for some reason this is not easy to do, as the decision was taken to put the boat back in the water with the prop still loose. 

 

My guess is both the prop and the shaft need replacing now it has been run with the prop loose, say £600 for the prop, £500 for the shaft, say £1,000 to lift the boat and put it on hard standing for a fortnight while the new shaft and prop are sourced. Plus say £500 labour for the engineer to fit both. So £2,600 all in to fix this. Just my estimate, assuming it turns out to be a simple fix. 

 

The £2,600 cost *could* be the reason it was just plopped back in the water rather than fix it. 

 

 

 

 

 

 

 

 

 

 

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Lighten up guys - he has made up his mind, he is prepared to be told 'we told you so' in a few days / weeks time, he knows what he is getting into, he didn't get the support he was probably expecting, & no one said 'it'll be fine'. So there seems little point in going round and round.

 

1 hour ago, tehmarks said:

I've made my mind up what I'm going to do (buy the boat), and I'm looking for informed opinion on something I don't really have the knowledge to form an opinion on (how urgently a loose prop will need looking at). The opinion is clearly that it needs looking at urgently, so that is what I'll do.

 

What I do have is a rough idea of what it could cost me, and I'm perfectly happy with that.

 

2 hours ago, tehmarks said:

I don't consider that I'm relying on the survey; it was good confirmation of the impression I got with my own eyes while poking around the bits you might expect to be rusty, damp or dodgy, and I'm happy with the risk I'm taking on by not having a survey carried out myself. And when I sink in three months time, you can tell me you told me so!

 

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1 hour ago, Mike Tee said:

If the previous owner put it back in the water knowing the prop was loose, what other problems / lack of maintenance has been ignored? It just indicates a mind-set of the previous owner, and not a good one.

Yes, which is another reason I wouldn't rely on his survey. But it's your money.... Good luck.

Edited by blackrose

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Not safe to use, if it falls off you have no brakes, could cause a serious collision and damage to a lock etc.

 

There is a good chance that the wear will be in the softer bronze of the prop. I would take it off whilst the boat is in the water, should be simple if its already loose, and let Crowthers have it for repair.

 

The taper should re-bite when it is tightened  back on, but drilling the shaft for the split pin will need it at least up out of the water at the stern.

 

Just a thought.........is this a Vetus shaft and prop? They are held on with a nut (includes an anode) with a tab washer to lock it.

 

They are infamous for shedding props.

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I would want to know how the loose prop was diagnosed. At first sight a simple loose prop should have a fairly easy initial fix by tightening the nut to see what happens. If it won't tighten then something more serious is wrong. I am wondering if that 5 degree movement might be backlash in the gearbox or a loose coupling. If it is the gearbox that could be even more expensive. Its vital the OP establishes exactly where the backlash is.

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17 minutes ago, Tony Brooks said:

I would want to know how the loose prop was diagnosed. At first sight a simple loose prop should have a fairly easy initial fix by tightening the nut to see what happens. If it won't tighten then something more serious is wrong. I am wondering if that 5 degree movement might be backlash in the gearbox or a loose coupling. If it is the gearbox that could be even more expensive. Its vital the OP establishes exactly where the backlash is.

Good point Tony. 

It could be anywhere in the drive train or even a worn stern bearing allowing the shaft to lift.

Some details and/or pictures of the type of coupling and gland would help.

5 degrees is a tiny amount to estimate at the shaft, an eighteenth of a rotation. If the prop is around 17" in diameter it is about 3" at the prop which is a lot. Is it really so loose?

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Nothing to do with a loose prop, (unless the shaft is worn and stern gland leaking) but shows an extreme example of what can happen if you rely on the sellers survey :

 

The vessel was fitted with an air cooled Lister engine and, in accordance with common practice, had a ventilation jalousies cut into the topside aft to give the necessary combustion air supply for the engine. The overplating was such that the jalousie at the engine room was within 65 millimetres of the waterline. That highly dangerous situation was not helped by the presence of a small lop on the water surface. Some five people plus a dog called Gus were on board (three of them sitting aft and two in the cabin) to make the journey and, hearing unusual noises from the engine, the engine room cover was lifted and the boat was found to be rapidly taking water. The situation was made worse by all of the people on board moving aft to have a look and to try to bale the water out, thereby increasing the trim and pushing the lower edge of the jalousie 50 mm under the water. The boat rapidly filled and sank within 10 seconds but, fortunately, a nearby RIB and a police boat arrived within two minutes and all personnel, plus Gus the dog, were picked up by the police and the nearby RIB. Despite the fact that none of them were wearing life jackets and at least one of them could not swim, there were, thankfully, no fatalities although all were suffering from shock. What Gus said was not recorded. It was later said that the owner had relied on a marine survey report prepared for the previous owner

 

https://www.iims.org.uk/the-dangers-of-overplating/

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6 hours ago, Boater Sam said:

Good point Tony. 

It could be anywhere in the drive train or even a worn stern bearing allowing the shaft to lift.

Some details and/or pictures of the type of coupling and gland would help.

5 degrees is a tiny amount to estimate at the shaft, an eighteenth of a rotation. If the prop is around 17" in diameter it is about 3" at the prop which is a lot. Is it really so loose?

I'll try that again. 5 degrees at the shaft is one seventy second of a full rotation. At the prop edge it is about 20mm. So how much is it moving?

 

I was hungry, maths doesn't work with a growling stomach.

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I think the costs mentioned might be a bit on the high side. I had the prop replaced, a new taper machined on the shaft and stern gland repacked with change from £1000. No, the stern gland was repacked with the proper stuff, not bank notes. Doesn't include dry docking as we had the blacking done at the same time. About 8 years ago so add a bit for inflation.

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