Deep sea seals

[SAWDOC]

I see from previous posts that Deep Sea Seals have a reputation akin to infectious ailments around here but has anyone ever had the experience of one failing suddenly or otherwise? Am I right in thinking if the bellows is visibly sound the seal is secure?

 

[Marsupial]

I see from previous posts that Deep Sea Seals have a reputation akin to infectious ailments around here but has anyone ever had the experience of one failing suddenly or otherwise? Am I right in thinking if the bellows is visibly sound the seal is secure?

Not personal experience but a pal of mine had one fail suddently while crossing the North Sea from Harwich to Ostend. After bailing for a few hours, upon arrival in the early hours of the morning he persuaded the harbourmaster in Belgum to let him have the keys to the crane so he could save the boat from sinking, he did. This was 1988; I dont think you could do that today! Yes he was a self reliant type, calling for a lifeboat would only happen after he stepped up into the liferaft.

 

[Tranona]

They are no longer actively marketed in the UK. Like all face seals they rely on the pressure of the bellows to keep the faces in contact. The one face seal on the market that seems to be successful is the PSS. Compare the bellows of this design with the Deep Sea. The Deep Sea which is made (I think) in Australia has an emergency clamp - presumably for when it fails.

Lip seal designs such as the Volvo, Tides Marine or Vetus seem to have taken the non-traditional stuffing box market in both OE and replacements.

 

[NorthUp]

The 'emergency clamp' on the Deep sea seal is used to clamp off the sterntube part, so the seal faces can be opened out for inspection or maintainance, or if the seal is damaged- but you cannot rotate the shaft while clamped.

Not many about these days as Tranona says, I recall that Wartsilla deal with them now, on the big ship side (at big ship prices!)

Go for a Volvo type lip seal if it will fit your stern tube/ shaft diameter combination.

 

[Bishop Terrorchoke]

I have heard of it

I see from previous posts that Deep Sea Seals have a reputation akin to infectious ailments around here but has anyone ever had the experience of one failing suddenly or otherwise? Am I right in thinking if the bellows is visibly sound the seal is secure?

Friends used to charter out a small yacht which had either a PSS or Deep Sea shaft seal, can't remember which. It failed catastrophically in the Clyde one day and the boat was towed into Rothesay by the lifeboat with water over the cabin sole, much to the alarm of the charterers. I believe the bellows tore when an engine mount went.

As others have said, a Volvo lip seal is the way to go if there is one to fit your shaft. I also think it is worth considering what emergency action you would take in the event of sudden seal/stuffing box failure. Having some sort of temporary fix handy might be a good idea.

BishopT

 

[30boat]

Even if they don't fail they're remarkably hard to set up squarely so they tend to leak slightly.That's my experience anyway,I had them for 8 or 9 years in two boats.On top of that they're more expensive that the Volvo Seal .

 

[pohopetch]

We have had a Manecraft Deep Sea Seal seal in our yacht for 9 years with no major problems - last 3 years has been continuous use. They are readily available in the a UK. Just bought a new one from T Norris Marine ex-stock - http://www.tnorrismarine.co.uk - to replace the existing one as a matter of routine maintenance although the old one does seem fine. It only ever once "stuck" on us. After not running the engine for 3 or 4 months the two surfaces had stuck together so when the prop shaft was rotated it attempted to rotate the rubber bellows and this work a bit lose and let some water in until I freed it up and retightened everything. As long as you have good access I think a routine check of the drive drain and seal is a good thing and you would see any impending problem with the bellows failing or a slow leak. If you had no easy access to the shaft seal then maybe the Deep Sea Seal is not the best option. Replacement set for our 1 1/2" shaft was £198 a month ago.

Cheers
Peter

 

[Bosun Higgs]

Had a couple of deep sea seals - both were the early ones. Neither failed suddenly but both failed fairly rapidly. They both suffered from the seal "welding" itself to the ring and the twist until it unwelded itself always used to worry me.

Went to the lipseal types instead and now the Volvo. Of the three I prefer the lip seal ones.

 

[Ruffles]

We had one for many years.

If the shaft gets wet or oily the bit that clamps to the shaft can lose its grip and slowly move towards the engine. The pressure on the sealing ring will be reduced and it will leak. Rather than tightening the clip which will cut into the rubber put a second clip on the shaft against the edge of the rubber so that it cannot move. Two smaller clips clamped head to toe would be best.

If the boats not been used for a while, before starting the engine, spin the shaft by hand to break any incrusted verdigris on the bearing surface. I would do this when opening the engine sea cock.

Mine always leaked very slightly with the engine idling. Caused I think by the increased amplitude of the vibration at low speeds.

Like many others, I replaced it with a Volvo seal. Mainly because I wanted a dry bilge, not for reasons of safety. It also seems to give some support to the shaft and so reduces vibration.

 

[Ruffles]

Went to the lipseal types instead and now the Volvo. Of the three I prefer the lip seal ones.

I think the market in shaft seals is really odd.
I replaced the seals on a raw water pump and discovered that a one inch triple seal only costs a couple of quid. Surely you could turn up a stainless steel housing to take two of these seals, connect it to the stern tube with that stiff rubber hose and you'd have something that lasts for ever? Or an I missing something?

 

[PCUK]

MY DSS failed and filled the engine compartment with water. Dirt got between the faces while running and allowed large amounts of water to spray in.
Pulled back the rotating part and wiped the face, increased the pressure and it was OK again. Now use PSS which are far more robust and reliable.

 

[SAWDOC]

. I also think it is worth considering what emergency action you would take in the event of sudden seal/stuffing box failure. Having some sort of temporary fix handy might be a good idea.

BishopT

Exactly.

Routine visual inspection.

Include a replacement seal in the on board spare parts box.

Errrr.....

Any other bright ideas?

 

[JimC]

I had a Deep Sea Seal for 5 years in my last boat and it never gave any trouble. I was told it had already been in situ for 2 years. It has since served another year so that's 8 years altogether. Some of the engine cooling water was bled off and forced into the seal through the moulded-in rubber pipes. I feel this is important in getting the best out of these seals. It lubricates the abutment faces and flushes away any debris that get between them.

 

[PCUK]

Didn't on mine!

 

[roger]

Stopelo Seal

I bought a Stopelo Seal in Dunkirk in 2001, fitted it that winter and have used it ever since with no problems. I couldn't work out which spares to get so bought another complete one in 2003. It's still in it's packing on the boat.
It is of the conventional type rubber bellows clample to shaft tube with graphite disk also clamped with jubilee clips. On the shaft is a stainless steel disk with internal "O" rings to prevent leakage along shaft. You will find it on the web. Cost in 2001 was about 100 pounds. You just have to remember to flood the seal every time the boat goes into the water - or dries out.
PS I've just looked on the web. Various vendors have it but I have not found the 35 mm. one that I have. I would not expect them to supply imperial sizes because it is a French device.

 

[Bosun Higgs]

I think the market in shaft seals is really odd.
I replaced the seals on a raw water pump and discovered that a one inch triple seal only costs a couple of quid. Surely you could turn up a stainless steel housing to take two of these seals, connect it to the stern tube with that stiff rubber hose and you'd have something that lasts for ever? Or an I missing something?

No you're not missing anything. Lots of engineers in our club and many of them did exactly what you suggested using phosphor bronze.

I used to replace the seals every couple of years simply because they were so cheap.

 

[PetiteFleur]

When I re-engined my boat a few years ago I fitted a Volvo seal. I did have to replace the bronze 'spigot' bolted to the inside of the boat to accept the diameter suitable for the Volvo seal. A firm in Norfolk machined one to my dimensions for not a lot of money. Can't remember who it was but if anyone is interested I'll dig out the invoice.

 

[Blueboatman]

The previous owner of my boat had one fail while motoring up the Portugese coast-so not due to sticking faces or loose engine mounts or excess shaft movement through overzealous reversing or catching a lobster pot..it just suddenly let go and slid up the shaft enough to let a lot of water into the boat (boat has a very deep bilge)..
In fact there's a bit of a history of DSS failures on this type of boat, one 'modification being to fit a piece of plastic pipe between the DSS and the gearbox flange so the DSS has nowhere to go if it loosens...
First thing I did when I bought the boat was to fit a volvo lipseal ( and I carry a new spare one of those too)..Neat simple and inexpensive.

I think when DeepSeaSeals first arrived, they were regarded as a great thing offering a dry bilge !

 

[Danny Jo]

There was one on my boat when I bought her four years ago. The surveyor sensibly advised having it professionally checked, so I asked the yard where she was lying to check it. Their response was something along the lines of "it looks OK". It started to dribble unpredictably the following year, so I always checked for leaks after stopping the engine. But I made the mistake of letting the man who was checking the electrics start the engine without detailing my shut-down routine. Result: 200 litres of water in the bilge 4 days later (and it was lucky I checked it then). The seal was probably around 9 years old, well past its recommended replacement date, but I learned that too late.

The problem is that one face wears a groove in the other, and if there is any lateral movement in the shaft (as there was with mine), that face can end up resting on the shoulder of the groove, breaking the seal. The photo below shows what the wear looked like on mine. I replaced it with a Volvo lip seal, but if they had been readily available I might have used another Deep Sea seal, and replaced it every 4-5 years. The Volvo is OK, but unlike the Deep Sea seal I have to vent the air by hand regularly (every 3-4 hours if the engine is running continuously) and if I don't, it overheats.

 

[gerry99]

I was talking to the marine engineers at my yard, and they said from their experience the Volvo ones were the best depsite them being relatively lower cost than competitors, the advice was if there was a Volvol one available for my yacht and propshaft diameter then go for it, otherwise the next recommendation would be the PSS seal.