Manecraft deep Sea seal leak

[phil28]

Hi everyone!

I see there has Been quite a lot of discussion on the reliability of the deep sea seals. I would love to know now if anyone has any suggestions on my current problem.

I recently purchased a boat in tollesbury which was moored on a Mud berth over winter. We proceeded To sail the Yacht to dunkerque And motored through the canals. About a quarter of the way through we noticed quite a lot of water in the bilge and traced it back to the seal. At first we did not have much of a leak but we are now currently on our way to Barcelona after sailing/motoring around the Balearics. The leak seems to be steadily getting worse.

I have uploaded a video of the leak and the shaft rotation.
https://www.dropbox.com/sh/ek3uwbe4i6m67fn/AAAHhSGxI9CUFSNWx-h9MN84a?dl=0

Wanting to know what people think of the shaft alignment as well.

First of all, is there any way of telling if the leak is caused by wear on the seal or from my shaft being slightly out of alignment?
There has always been a slight knock in forward gear which gets worse at certain revs.

Second, what is the best plan of attack? Can I re seat the rubber seal to be closer and hopefully that will work? Or will it need to come out of the water and replaced?

What is everyone's views on the reliability now? Am I risking it to keep going the way it is?

Also does anyone have any contacts for repairs in Barcelona/badalona?

Cheers in advance for any help you can provide!!

You guys are life savers

 

[macd]

I've no special knowledge of this seal, I'm afraid, but there are many previous threads which may help.

For starters:
http://www.ybw.com/forums/showthread.php?159514-Manecraft-shaft-seal&

http://www.ybw.com/forums/showthread.php?29224-Manecraft-Propeller-Shaft-Seals&

http://www.ybw.com/forums/showthread.php?77211-Deep-Sea-Seal&

 

[Tranona]

Get rid of that seal as quickly as you can. It is a very poor design. Its weaknesses are the inadequate rubber bellows and faces that suffer rapid wear. In your case not helped by the shaft being either bent or severely out of line and the engine mounts probably shot.

The vibration is causing the faces to rub against each other and wear which is allowing water to get int. Little you can do as even if you compress the bellows it will only increase the wear.

Motoring through the canals in that state has brought the problem to a head. You ought also to check the prop as you may have hit something and damaged it which also may be the cause of the vibration.

 

[vyv_cox]

I fear that no seal on earth is going to last for long with such excessive shaft movement as you seem to have. Engine movement seems considerable, you could look at alignment while still afloat and attempt to equalise the loading on the mounts. It's also possible that one or more mounts have failed.

Measure any offset of the shaft very simply by setting up a pointer or a piece of chalk near to the coupling and rotating the shaft by hand. This will tell you if there is any offset in the coupling itself, which you may be able to correct by changing its position (moving round one or two bolt holes)

 

[Snoopy463]

I bought my Achilles 9m that was fitted with such a seal number of years ago. It was previously moored on a swinging mooring in Milford Haven. After a couple of years in a mud berth in the Bristol Channel the seal started leaking. Changed for another of the same, mainly because of the limited room and all went well for two years. Then leaks again. Replaced by a conventional stuffing box and all's well. I guess the mud acts as a grinding paste that erodes the bronze face. The dark composition material of the other face seems made of sterner stuff.

 

[phil28]

Thanks very much for your replies everyone!

I feared the shaft may have been out of alignment

As for testing with the chalk I don't quite understand how you mean. How exactly would i test and change its position?

Sorry for being a bit of a novice, have not had to deal with stern drives before.

Is there a way to tell if any of the mounts are shot?
If so is this something that could be fixed on the water?

 

[vyv_cox]

Thanks very much for your replies everyone!

I feared the shaft may have been out of alignment

As for testing with the chalk I don't quite understand how you mean. How exactly would i test and change its position?

Sorry for being a bit of a novice, have not had to deal with stern drives before.

Is there a way to tell if any of the mounts are shot?
If so is this something that could be fixed on the water?

Clamp the chalk close to the shaft. Doesn't need to be anything sophisticated, anything that holds it in position fairly steadily. Rotate the shaft by hand so that the chalk marks any high points. You can do it with just a pointer if you prefer but the chalk method marks the place better. Assuming you find that the shaft/coupling is offset, loosen the bolts and push in the opposite direction from the high point. It may just be that the holes in the coupling are oversize. If this does nothing, try removing the bolts and repositioning the shaft flange 90 or 180 degrees out to see if this can fix it. If the chalk test shows the shaft/coupling to be true the problem lies elsewhere.

Inspect the mounts for breaks in the rubber by levering up each one in turn, gently. Inspect the brackets holding them to the engine and its beds. These sometimes fatigue and snap. If these are all OK you might check alignment by loosening the coupling bolts and checking the clearance between the flanges, top, bottom and sides. They should be the same within a few thousandths of an inch.

All of this can be done on the water.

 

[Tranona]

Posted a reply saying much the same as Vyv, but think it got lost.

Just for clarification, it is not a stern drive, but a conventional shaft drive through a stern tube, and judging from your photo of the boat in your blog, there will likely be a P bracket supporting the shaft just in front of the prop.

The amount of movement suggests that if everything is OK inside, then the shaft could be bent, the P bracket bent or loose, the bearing inside the bracket worn or the prop damaged. This could be inspected by a diver but probably better to lift the boat. Any repairs in this area will need to be done out of the water anyway.

 

[pcatterall]

Sorry, it does look bad !! hopefully some of the suggestions made may help sort any alignment issues inside the boat.
I fear that on the engine there could soon be a rapid deterioration in the tube/seal area. depending on weather conditions if you are confident that you can proceed under sail and save any motoring for in marinas etc you may consider taking the risk in continuing to Barcelona. With my seal completely out my small pump could easily handle the amount of water coming in. Possibly the leak may not be to bad when sailing provided the shaft doesn't turn and possibly there is a stationary prop position where the leak is very small?

We are too far from Barcelona to offer advice about local repairs but someone here or on the live aboard forum will have some ideas.

Good luck

 

[phil28]

Thanks everyone for your input.

We are currently on the last stretch towards Barcelona, once we get in I'll check all the things as suggested. Will get back to you all with how I go!

Cheers

 

[phil28]

Quick update.

The seal leaks a lot more when I hear the strong knocking noise. If I adjust the revs, whether up or down until the engine (lack of a better word) is in sync and sounds smoother,the engine shakes a lot less and the knocking sounds dies down and less water is coming through the seal.

Also added a couple more videos to the drop box folder
https://www.dropbox.com/sh/ek3uwbe4i6m67fn/AAAHhSGxI9CUFSNWx-h9MN84a?dl=0


In my head this seems like another thing pointing to engine mounts? Please correct me if I am wrong?

Cheers again

 

[wizzer]

I just replaced two of these on my twin engine installation Seaward 25 during a winter refit, spent a lot of time ensuring they were fitted right & making sure that the engine / shaft alignment was as near perfect as I could get it. When I look down at the shafts when underway, there is virtually no out of place movement. I reckon you're asking a lot of that Manecraft seal to do its job under those conditions. Something is certainly out of line or maybe even a cutlass bearing is out of place or badly worn. Get it checked as soon as poss. Good luck in the meantime.

 

[phil28]

Get it checked as soon as poss. Good luck in the meantime.

The more I look into it the more I see how out of alignment it is. Only 25 miles out now so all should be okay ��
Thank you!

 

[phil28]

We have made it to badalona! After emptying nearly 40L over a 12 hour day.

I have done as vyv_cox has suggested by checking the alignment with a fixed marker.

On the coupling end I have found no misalignment however on the seal end of the shaft the shaft seems to be very bad. The marker covered about 180 degrees of the shaft.

Moving the shaft up and down it seems to have a lot of play through the stern tube (see video)
https://www.dropbox.com/sh/ft1dwlastwo07vj/AAAldCNOiqzq0_Dm7n72V77la?dl=0
Is this likely where a lot of the problem lies?

In regards to engine mounts it seems alright from what I can see but I cannot be sure if they are shot completely.

Is the best bet going to be getting the boat out. Removing shaft, checking if it is bent. Replace bearing, have engine realigned and balance prop?

Does anyone have any idea what kind of price I will be looking at?

Cheers again for the help!

 

[Fr J Hackett]

All the checking work should be easily done by yourself so then it's the cost of haul out, new engine mounts are again a relatively easy self fix, stern tube is not that easy but depending on tools available not difficult nor is alignment if the prop is damaged and out of balance which I suspect it is not as you would see a problem at all revs it may be cheaper to get a new prop. Long and short you can minimise costs by doing a fair bit yourself. As to costs others will be able to advise hopefully.

 

[Pete7]

Phil, I can't believe that you can move the shaft like that. Something seriously wrong with either the engine mounts or the cutlass bearing, no wonder the seal leaks.

Suggest lift out, check and replace cutlass bearing, check shaft is straight, replace seal with the Volvo one if it will fit, refit and then check alignment of engine and condition of engine mounts.

Pete

 

[Tranona]

Pretty sure you have a P bracket and it is either the cutless bearing in the bracket that is worn or the P bracket is loose. another possibility is that thee is a bearing in the stern tube, but that is unlikely as normally that would require a flexible coupling at the gearbox end which you don't have.

Replace that seal with a Radice one piece seal - far better than the one you have. The little red handle is to lock the seal because they have a history of failing. "Sold" as a safety feature but in reality a bodge for an inadequate design.

 

[geem]

Get rid of that seal as quickly as you can. It is a very poor design. Its weaknesses are the inadequate rubber bellows and faces that suffer rapid wear. In your case not helped by the shaft being either bent or severely out of line and the engine mounts probably shot.

The vibration is causing the faces to rub against each other and wear which is allowing water to get int. Little you can do as even if you compress the bellows it will only increase the wear.

Motoring through the canals in that state has brought the problem to a head. You ought also to check the prop as you may have hit something and damaged it which also may be the cause of the vibration.

Your comment is not correct. These seals are used in commercial water pumps and dont leak. I know of several that run at very high speed continuously 24/7/365 for years without a drip. The difference is that in these installations the alignment is perfect. If you install this kind of seal on a shaft that is bent or has longitudinal movement then you will have a leak. It is not a problem of the seal but the installation. We have an appropriate installation on our boat that has no longitudinal movement and we have never had the slightest drip. On a boat these seals will last many years if installed correctly.

 

[macd]

Phil: if you do go for a Radice or Volvo seal, research them early. Both are available to fit only a fairly small range of stern tube sizes (the Volvo being the worst in this respect), which might oblige you to source an adaptor. I believe both are made by Radice, so there's little to choose between them in terms of quality, but the ease of greasing and self-burping qualities of the Radice are well worth having.

Fitting dimensions (and prices) here, under 'RMTA' (apologies for the Manecraft on the same page :ambivalence:
https://www.google.com/url?sa=t&rct...qGu4wOH3JfCCvSR6Q&sig2=g76N_bHkvSTKFhbjYGaEAA

 

[ibbo]

Regarding the Manecraft seals, I just replaced one that was 15 years old, and would have still been going strong apart from the mild steel bolt that had been placed in the fitting for the bleed hole. this had rusted and split the tube.

As Geem says, if the alignment is true, then these are a perfectly adequate seal.

I have replaced it with a new one the same.