Stern Gland repacking

[Stehughesie]

Hi.

Just blacked boat for first time at dry dock. When returning noticed constant drip from stern gland (1 drip every second) which needed pumping out via bilge pump. This drip was despite greasing stern regularly throughout 8 hour journey on return from dry dock. Appeared drip got worse once moored up and engine turned off. Read lots about tightening stern gland and repacking but noticed our boat doesn't have typical bolts that can be tightened. Any ideas on how I can tighten this type of gland very much appreciated.

Kindest regards

Ste

[Tracy D'arth]

The ring is designed to be tightened with a "C" spanner that has a hook on the end which fits in the hole. There are different sizes.

 

Like this one.   

 

 https://www.temu.com/subject/n9/googleshopping-landingpage-a-psurl.html?_bg_fs=1&_p_rfs=1&_x_ads_sub_channel=shopping&_x_vst_scene=adg&mkt_rec=1&goods_id=601099514259999&sku_id=17592201933680&_x_ns_sku_id=17592201933680&_x_ads_channel=bing&_x_gmc_account=3429411&_x_gmc_catalog=1080172&_x_ads_creative_id=82051425073856&_x_ns_device=c&_x_ads_account=176202708&_x_ns_match_type=e&_x_ns_msclkid=b0a4858d0a0b14ef3f33e0df556b6465&_x_ads_set=519380741&_x_ns_source=s&_x_ads_id=1312819189012688&msclkid=b0a4858d0a0b14ef3f33e0df556b6465&adg_ctx=f-8574a187

 

There is conventional graphite impregnated stuffing in the space behind the ring.

 

 

Edited November 13, 2023 by Tracy D'arth

[Stehughesie]

You are a star, thank you.

I'll buy a spanner and tighten it up, hopefully should do the trick. Can I ask what is conventional graphite stuffing (assume it's like a putty) and if you can continue tightening until end of thread. I've read about tightening just enough so as shaft turns without too much friction.

I'm new to boating and it is amazing that you have helped me so quickly and eased my mind.

[Tracy D'arth]

Its cotton weave in various thicknesses impregnated with graphite , find the size by using a twist drill that will fit in the gap when the ring is out.

https://www.force4.co.uk/item/Force-4/1-4---615mm-x-05m-Gland-Packing/G9M?stock=21082&msclkid=6e08438fa40e199fcb0326ddc761ed40

 

[ditchcrawler]

You can also get PTFE stuffing

[springy]

You may need two C spanners of different sizes - the lock ring looks slightly larger than the "nut", and you may need two separate spanners so that you can tighten the lock ring whilst holding the "nut" in the required position.

The "nut" is nearest the gearbox, the lock ring immediately before the stern tube.

 

 

springy

[Stehughesie]

Is it a case of holding the larger lock ring tight then turning the nut clockwise to tighten then? Seems logical as this would reduce gap between the two and hopefully compress the graphite rope improving the seal?

Thanks for the advice

[Bee]

Yes, I think so, it looks as though there is plenty of packing still in there. Ideally it shouldn't need to be tightened very much, overtightening can cause the packing to wear the shaft, sounds unlikely but it really will, the shaft on my boat is a second hand one with some quite deep grooves but they miss all the vital bits. One cause of drips is a misaligned engine, this will cause a shaft to run in an oval or something that is not a true circle, this means that the packing, which is quite hard stuff, cannot press equally all round the shaft so it drips. 

[springy]

First release the tension on the locking ring (anticlockwise) whilst holding the "nut" still, then gently turn the "nut" clockwise to compress the packing, hopefully you can get the drip to stop whilst still being able to turn the shaft by hand fairly easily. Finally tighten the locking ring clock wise whilst holding the "nut" still. Check again that you can turn the shaft by hand. If you overtighten the packing it will run hot and wear the shaft.

 

springy

[Tony Brooks]

18 minutes ago, Stehughesie said:

Is it a case of holding the larger lock ring tight then turning the nut clockwise to tighten then? Seems logical as this would reduce gap between the two and hopefully compress the graphite rope improving the seal?

Thanks for the advice

 

This could be misinterpreted.

 

1. Hold the adjuster tight with the spanner and loosen the lock ring several turns.

2. Gradually tighten the adjuster while turning the shaft be hand, maybe use the coupling, until the drip just about stops or you get one or two drips a minute.

3 tighten greaser which should seal the gland, and if you adjusted it until the drip just about stopped ensure a bead of water or grease appears by the shaft. Do not tighten it, so you can't turn the shaft.

4. Hold the adjuster and tighten the locking ring down tight.

 

Note, a Lister LH150 gearbox or and old one with planet and a sun gear may render it impossible to turn the shaft.

[Stehughesie]

Thank you so much Bee, Springy, Ditchcrawler and TracyDarth. Fantastic advice

[Stroudwater1]

Could the boat being out of the water dried things and caused this though ?
 

Ours seemed to be more prone to drops for some while after being out for 2 weeks pending hull work. All is good now and hardly get a drip a week. Just kept tightening the greaser twice a day till tight, didn’t do anything else.
 

Took a year to subside though it never dropped as badly as the OPs boat. 

[Stehughesie]

Drip gets worse after few hours travelling and when engine turned off. Greasing seems to then stop drip until boat moves again. Drip is concerning, say once a second, so fair amount needed pumping out after few hours.

Pretty sure the c type wrench will tighten the gland and solve the problem.

Thanks for everyone's help

[Tacet]

3 hours ago, Tony Brooks said:

 

This could be misinterpreted.

 

1. Hold the adjuster tight with the spanner and loosen the lock ring several turns.

2. Gradually tighten the adjuster while turning the shaft be hand, maybe use the coupling, until the drip just about stops or you get one or two drips a minute.

3 tighten greaser which should seal the gland, and if you adjusted it until the drip just about stopped ensure a bead of water or grease appears by the shaft. Do not tighten it, so you can't turn the shaft.

4. Hold the adjuster and tighten the locking ring down tight.

 

Note, a Lister LH150 gearbox or and old one with planet and a sun gear may render it impossible to turn the shaft.

Above advice is good.

 

The "do not tighten it, so you can't turn the shaft" relates to 2) rather than the tightening of the greaser in 3)

 

The "tighten greaser" in 3) could equally be described as "operate greaser".  It does tighten insofar as it becomes more difficult to turn, but that is not the direct aim.

[Scholar Gypsy]

On 13/11/2023 at 20:31, Stroudwater1 said:

Could the boat being out of the water dried things and caused this though ?
 

Ours seemed to be more prone to drops for some while after being out for 2 weeks pending hull work. All is good now and hardly get a drip a week. Just kept tightening the greaser twice a day till tight, didn’t do anything else.
 

Took a year to subside though it never dropped as badly as the OPs boat. 

My stern tube now drips much less after a week out of the water in September (for blacking). Very strange! 

[Tony Brooks]

50 minutes ago, Scholar Gypsy said:

My stern tube now drips much less after a week out of the water in September (for blacking). Very strange! 

 

I don't think so, unless the boat is fully supported the hull will twist, hog, sag in any combination, so the shaft ends up slightly out of alignment. Once it is back in the water and supported along its length, it takes a while for the hull to go fully back to its normal floating shape. On the fleet, we never aligned the engine until at least 24 hours after it was refloated.   While it is out of the water, many boaters will find doors and draws jambing.

[Scholar Gypsy]

1 minute ago, Tony Brooks said:

 

I don't think so, unless the boat is fully supported the hull will twist, hog, sag in any combination, so the shaft ends up slightly out of alignment. Once it is back in the water and supported along its length, it takes a while for the hull to go fully back to its normal floating shape. On the fleet, we never aligned the engine until at least 24 hours after it was refloated.   While it is out of the water, many boaters will find doors and draws jambing.

Yes, I had one door bolt that  was a bit sticky....