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Stern gland packing

We do around 200/250 hrs each year enjoying canal cruising. Can you give me a guide as how long the the stern gland packing should last - say 2/5/10 yrs? Thanks

Asked by: Chris Marriott  | 8.37pm, Wednesday 29 April

WW says:

Sometimes you can have many years of life, sometimes less, it depends on many factors, including engine/props haft alignment, water quality (amount of grit, etc) and how well lubricated the stern gear is.
All below assume traditional grease-lubricated stern gear- water lubricated gear is different.
The gland packing can be topped up, and even replaced afloat (given experience!), rather than a full overhaul. Unless the gland packing has run very hot, or the plain metal bearings at the aft end are very worn, it my be beyond five years before any full replacement is needed... Quit ten even longer.
To reduce the likelihood of the stern Gland needing full replacement , always ensure that there is good lubricant levels, that the stern gland runs cools (there should be at least one drip a second when the prop shaft is turning. Don't be tempted to put so much grease in, or tighten the packing nuts too tightly, as the gland can then run too hot, which shortens the life of the packing (and the bearings). Ensure that the engine is properly aligned so that lateral vibration is minimised.

Mark Langley  | 9.39PM, Wednesday 29 April

One drip per minute is not really enough. Although a drip every second sounds a lot, it only equate to a litre every 4 hours or so, and that should be only whilst the shaft is turning.

Rupert Smedley  | 3.13PM, Saturday 2 May

One drip a minute from a conventional stern gland is definitely not enough- a Rupert says, its only a small volume of water; and if not enough comes through, certainly on rivers or cruising hard, the gland will run hot.
If you are cruising a long pound, when you get to the next lock, lift the deckboard and feel the stern gland (taking care around the propshaft- stopping the engine may be sensible) It should feel cold ideally- or no more than body temperature, If it is hot, the packing is too tight- consider loosening the gland nuts

Mark Langley  | 5.50PM, Tuesday 5 May

Readers say:

Ours did 2500 hours before we had it repacked though I suspect it would have done quite a bit longer.
Mark, I always thought it was one drip per minute not per second from the stern gland?

Clive Dutson  | 2.33PM, Saturday 2 May

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