Stern gland lip seals

[Carib]

A slightly esoteric question.. I need to replace the oil seals in my stern gland (the type with an oil reservoir). Like these ones: https://simplybearings.co.uk/

Should I choose the R21 or R23 type described below, I wonder?

"Oil Seals or Rotary Shaft Seals are designed to provide a barrier to retain lubricant and to keep out contamination. They are available in metric and imperial sizes with a variety of sealing lip arrangements the most common of which are:

• R21 - Single Sprung Lip
• R23 - Single Sprung Lip with the addition of a wiper lip to help keep out contamination"

Many thanks

 

[Plum]

A slightly esoteric question.. I need to replace the oil seals in my stern gland (the type with an oil reservoir). Like these ones: https://simplybearings.co.uk/

Should I choose the R21 or R23 type described below, I wonder?

"Oil Seals or Rotary Shaft Seals are designed to provide a barrier to retain lubricant and to keep out contamination. They are available in metric and imperial sizes with a variety of sealing lip arrangements the most common of which are:

• R21 - Single Sprung Lip
• R23 - Single Sprung Lip with the addition of a wiper lip to help keep out contamination"

Many thanks

Can't say without knowing which stern gland, and what the arrangement of the seals are, but for sure, any lip seal that faces the seawater must have a stainless steel garter spring.

Www.solocoastalsailing.co.uk

 

[Carib]

Yes, definitely a garter spring, thanks - the question is do I order a "wiper lip" (r23) type or not (r21).

It's like the one on Vyv Cox's site here (Bukh type). I believe it has two back to back seals on the 'sea' end (to keep the water out and oil in respectively), one on the engine end (to keep the oil in).

 

[rogerthebodger]

Yes, definitely a garter spring, thanks - the question is do I order a "wiper lip" (r23) type or not (r21).

It's like the one on Vyv Cox's site here (Bukh type). I believe it has two back to back seals on the 'sea' end (to keep the water out and oil in respectively), one on the engine end (to keep the oil in).

If you have 2 lip seals back to back you do not need the wiper lip as this is designed to keep any crud away from the lip so would be between the to seals and there should be no crud between the seals.

 

[Carib]

If you have 2 lip seals back to back you do not need the wiper lip as this is designed to keep any crud away from the lip so would be between the to seals and there should be no crud between the seals.

Excellent, thank you.

 

[RichardS]

These days I usually buy the double lip/wiper seals if they are available in the size I need. There is usually only a small price differential and I can't think of any reason not to go for the extra sealing/protection.

Richard

 

[Boater Sam]

These days I usually buy the double lip/wiper seals if they are available in the size I need. There is usually only a small price differential and I can't think of any reason not to go for the extra sealing/protection.

Richard

Agree but you definitely must have Stainless steel spring and lubricate the new seals and the gap between them well with silicone grease to make them last longer.

 

[rogerthebodger]

These days I usually buy the double lip/wiper seals if they are available in the size I need. There is usually only a small price differential and I can't think of any reason not to go for the extra sealing/protection.

Richard

This has been discussed before

lip seals

The OP talks about 2 seperate lip seals one stopping water coming in to the stern tube and the other stopping the oil inside the stern tube leaking out.

This is a classic application where a double lip/spring seal would be used

In most applications the lip only seals in in one direction. The extra wiper is to help any grip from getting to the outside of the lip which could damage the sealing lip thus allowing and fluid leakage

 

[RichardS]

This has been discussed before

lip seals

The OP talks about 2 seperate lip seals one stopping water coming in to the stern tube and the other stopping the oil inside the stern tube leaking out.

This is a classic application where a double lip/spring seal would be used

In most applications the lip only seals in in one direction. The extra wiper is to help any grip from getting to the outside of the lip which could damage the sealing lip thus allowing and fluid leakage

I know .... I have two or three posts in that thread.

Neither I nor the OP are talking about lip seals with two springs, which, as I said in my post #14 are extremely unusual and are probably too wide anyway. He's talking about the sort referred to in my earlier post in the thread and I cannot see any reason why he should not such seals as there is no downside.

Richard

 

[rogerthebodger]

I know .... I have two or three posts in that thread.

Neither I nor the OP are talking about lip seals with two springs, which, as I said in my post #14 are extremely unusual and are probably too wide anyway. He's talking about the sort referred to in my earlier post in the thread and I cannot see any reason why he should not such seals as there is no downside.

Richard

Yes but he does have 2 lip seals back to back which is in effect the same as 2 seals back to back.

This sealing element (2 seals back to back) does have 2 sealing springs

some Jabsco engine raw water pumps have 2 lip seals back to back to seal both the water in the pump and the engine oil. Jabsco use 2 seperate seals to allow a drain point in case one of the seals fail.

As I said the wiper is not necessary in the OP's application but I very useful in most single liquid sealing applications.

The OP could use a 2 single lip seals with a wiper but the wiper will not add any benefit in his application

 

[Carib]

Well, the price is the same - the only concern was that the extra lip might somehow affect the fitting or how they sit against each other. I need to get it right as removing the shaft is a pain! So if there's no issue here I may as well get the wiper ones.

 

[Carib]

looking in more detail, the choice seems to be Viton rubber + stainless springs
versus
nitrile rubber + carbon springs (albeit with a protective zinc coating).

Presumably the former is the one to go for?

 

[RivalRedwing]

stainless springs are essential, viton will probaby last longer

 

[Carib]

stainless springs are essential, viton will probaby last longer

Thought so, cheers. Here's me sitting down this morning thinking 'I'll just go online quickly and order those seals'