Stern gland drip

[Montemar]

I have a new ( to me ) boat with shaft drives and thus it has stern glands, stuffing boxes and mysterious things I never had before with my stern driven previous boat.
The stern gland is cooled by fresh water from the engine pump. It drips once every 7 seconds when the engine is off. Would this mean the water is coming up the stern tube to cause this or coming down the supply pipe from the cooling system?
Seawater coming in to drip seems strange, having a bilge to accomodate it is also new.
The manual for the boat (Broom 33) does not mention any special conditions when doind this other than cautioning against overtightening causing the gland to run hot..
The other shaft is about right dripwise.
I have the spanners to adjust it and previous owner claims they had new packing a couple of years ago so should I achieve the desired drip every 60 seconds with the engine ticking over or not?
I assume some water will always be present in the bilge.
I should be most obilged for any help!

 

[Divemaster1]

A picture of the setup would probably explain more, but if your setup is something like this;

Then I'd hazard to guess that the water is coming up from the higher pressure area along the shaft, rather than from the coolant water pipe... and a drip every 7 seconds when still is a bit high ... We allow for 1 drip approx. every 60 seconds when still ....

Adjusting this kind of gland is relatively easy by tightening the nuts, which compresses a couple of layers of Wax Seals (sterngland packing) which should be in there ... If you cannot tighten, or stop the drip, then the wax seal is worn/damaged and needs replacement (done when out of the water). Replacing the wax seal is easily done by loosening the nuts and pulling back the assembly... removing old seals and inserting new ones (two or more layers).

good luck !

 

[oldgit]

It is not usual for twin shafts to have different drip rates despite your best efforts to get them the same.
Mine have a slightly different set up to yours in that we have a little grease pump which you tweak every trip or so.
They always conspire to drip at different rates.
On some trips we can have several litres in one bilge but a teaspoon or two in the other.

 

[Greg2]

Sounds like they need tightening. Thing to do is tighten them a bit at a time. Once you have loosened the locking nut (aft of the packing nut) if they tighten easily I would probably start with a full turn and then quarter to half turns until you are happy with the drip rate. The rate when running is the important bit so you will need to adjust over time.

I recently replaced the packing on our Broom 41 and it is relatively straightforward as long as you can get access to the glands, which we can (we previously had an Ocean 37 and I had to change the packing with my arms through a tiny hatch working by feel)! If you do change the packing then use the old stuff to measure the lengths of the new and cut them at forty five degree angles at each end so that the ends overlap. You should get at least two pieces in the packing nut and three at a push. Don't expect it to be easy to get enough pieces in. Also ensure that the ends of each piece are not aligned with the ends of the preceding piece.

Tightening is probably the way to go first and only consider changing if that doesn't resolve it.

Hope this helps

 

[Montemar]

Many thanks for your very helpful replies.
I shall start to tighten it in stages this weekend.
Cheers!

 

[superheat6k]

If you are finding the stuffing boxes annoying then PSS seals are highly recommended, and quite easy to convert to (once the shaft is removed).

www.pyiinc.com

 

[Bandit]

Tides Marine Seals are the Mutts Nutts

 

[Montemar]

Thank you for the suggestion.
It would mean no water coming into the bilge at least by that route.

 

[omega2]

Leave them be, 7 second drip is nothing to worry about, and differing drips for different shafts is not unusual either, as stated we "dinosaurs" fire grease into ours but that does not stop them dripping either, but if you tighten them up too hard you will burn your shafts and then the drips will be dependent on where they stop turning, Fit a good bilge pump and an extra good auto switch "water witch" are the business.