Manecraft deep sea seal

[Crinan12]

I have a manecraft deep sea seal. It's the type with the red emergency jubilee type clamp.

It was installed when the engine was replaced in 2008 but has only done 450 hours.

I have been reading some horror stories about these particular seals.

Mine has never given me any problem.

Due to it's age (and design?) should i replace it when the boat is out of the water this winter?
Thanks

 

[Tranona]

Your choice. Never were the best bit of kit and anything that needs to have an emergency clip for failure on such a critical item seems odd.

Anyway, plenty of choice from the simple reliable Volvo/Radice type to more complex and expensive lip seals or face seals.

 

[Crinan12]

Thanks. I guess it will go on the to do list for the winter.
I've been put off my manecraft one by some of the comments I've read about them on here.

 

[LiftyK]

After many years of faithful service I replaced mine with a PSS seal when it started to drip. No more drips or needing to do burping after drying out.

 

[Bandit]

If it is 15 years old it is well past it’s normal life.

The Deep Sea Seal relies on the spring in the rubber cup to keep the water out.

I replaced mine at 7 years old when I drew the shafts to replace all the cutless bearings, the seal had gone hard and did not spring back and recover to it’s original shape , it was hard and glazed appearance. I have seen other failures of Deep Sea Seals and I would never use them.

I fitted Tides Marine Seals, and they are excellent. two inch shafts, you need to fit a good water feed to them and if a twin engine a crossover water supply.

We fit many Tides Marine Seals and have no problems an engineer I work with fitted PSS seals on his own boat and binned them at a year old and fitted Tides Marine which he swears by.

 

[Tranona]

After many years of faithful service I replaced mine with a PSS seal when it started to drip. No more drips or needing to do burping after drying out.

That does not sound like a Manecraft/Deep Sea seal which is a face seal just like the PSS only not as well engineered or made.

 

[geem]

That does not sound like a Manecraft/Deep Sea seal which is a face seal just like the PSS only not as well engineered or made.

The problem with changing from the deep sea seal for me is that no other seal will fit. The deep sea seal is very short compared to other seals

 

[Crinan12]

The problem with changing from the deep sea seal for me is that ho ther eeal will fit. The deep sea seal is very short compared to other seals

I wonder if that's why the previous owner fitted the manecraft one. I'll need to have a look and see how much space there is.

 

[Tranona]

The shortest seal is the Radice/Volvo at around 110mm for the smaller sizes. The limitation is that the diameter of the stern tube has only 2 sizes. The best alternative in my view is the Tides Marine lip seals which are simple and have a much wider range of fittings.

 

[geem]

The shortest seal is the Radice/Volvo at around 110mm for the smaller sizes. The limitation is that the diameter of the stern tube has only 2 sizes. The best alternative in my view is the Tides Marine lip seals which are simple and have a much wider range of fittings.

Neither fit my boat with 45mm shaft diameter. Too long

 

[Tranona]

Neither fit my boat with 45mm shaft diameter. Too long

Radice don't do a 45mm. The largest is 40mm which is 129mm long compared with 131mm for the compressed length of the Deep Sea. Trade off for the less than robust design of the Deep Sea compared with the PSS face seal or the Tides Sureseal.

A simple visual comparison between the bellows of a Deep Sea compared with a PSS (or the bellows of the Sureseal) will give you an idea of which one might be better on such a crucial item.

See post#5 for real world experience.

 

[geem]

Radice don't do a 45mm. The largest is 40mm which is 129mm long compared with 131mm for the compressed length of the Deep Sea. Trade off for the less than robust design of the Deep Sea compared with the PSS face seal or the Tides Sureseal.

A simple visual comparison between the bellows of a Deep Sea compared with a PSS (or the bellows of the Sureseal) will give you an idea of which one might be better on such a crucial item.

See post#5 for real world experience.

Yep, but only enough space for a deep sea on my boat. I would love to change it but nothing fit. We have the EM8 fitted to our shaft. As you say 131mm .long and its a tight fit between the plumber block and the seal

 

[LiftyK]

That does not sound like a Manecraft/Deep Sea seal which is a face seal just like the PSS only not as well engineered or made.

Mmm, it was many years ago when I made the change but Manecraft and the Derp Sea Seal names were exactly what I recall. I was advised to bend and burp the rubber seal if the boat had been dried out. No matter, it’s all in the past now.

 

[Tranona]

Yep, but only enough space for a deep sea on my boat. I would love to change it but nothing fit. We have the EM8 fitted to our shaft. As you say 131mm .long and its a tight fit between the plumber block and the seal

If you have a fully supported shaft then a Deep Sea is less of a risk. The weak point of all face seals in boats is that they don't like movement fore and aft or sideways which is common on many shafts on which are floating with a flexible engine one end and supported at the other end just in front of the prop. The bellows is the way of getting round this as it keeps the faces in contact while the engine/shaft moves about. The bellows is the weak point of the Deep Sea but the much more robust and larger type used by PSS seems to hold up well.

 

[geem]

If you have a fully supported shaft then a Deep Sea is less of a risk. The weak point of all face seals in boats is that they don't like movement fore and aft or sideways which is common on many shafts on which are floating with a flexible engine one end and supported at the other end just in front of the prop. The bellows is the way of getting round this as it keeps the faces in contact while the engine/shaft moves about. The bellows is the weak point of the Deep Sea but the much more robust and larger type used by PSS seems to hold up well.

Agreed. Our installation is somewhat different to most boats. The gearbox is connected to the propeller shaft via a truck prop shaft. UV joints each end and a sliding spider joint. The inboard end of the propellor shaft is supported by a 50mm diameter industrial plumber block. The 45mm shaft sits in the bearing with a split bush that locks into a groove in the stainless propeller shaft. There is no movement longitudinally due to this design. All parts are off the shelf SKF high quality stuff and not expensive. It's a very nice set up.
We don't have much problem with the deep sea seal normally, but a couple of months ago, it decided to leak. The bellows had slide down the shaft slightly. I had to push them back up and align them. We have had no trouble since. The last deep sea seal was on for 7 years. I wish I had kept that in place. Never had a problem with it