Gland packing

[chesapeake]

Has anyone any idea what size gland packng I need for my Princess 412-2.The shafts are 1 3/4 inch diameter and I am intending to repack them whilst in the water,has anyone else done this and could they let me know of any pitfalls........many thanks.

 

[Bandit]

Sinking while you re-pack your stern gland can be considered a pitfall.

 

[rosssavage]

It's either 8mm or 10mm. Get both, they're cheap enough. DON'T get the cheaper graphite impregnated packing (the dark grey / black stuff) as its carp - go for the tan coloured more expensive type. It's still cheap enough!

I did the packing on my P385 earlier this year whilst afloat, and whilst there is some water ingress it really isn't scary or dangerous (assuming you have a working bilge pump in the engine room!).

Cut four rings per shaft before you remove the gland insert thing, and remember to make the cuts at 45 degrees. Get these rings perfect or they will leak! Remove the gland insert bit - water will come in. Use a pair of long, thin self tapping screws and screw them into the first old packing ring. Use a pair of needle nosed pliers to pull on the screws to pull out the old ring. Some more water will come in. Repeat for the remaining old packing rings - there will probably be four in there, but it could 3 or 5 too, depending who last packed it.

When you get the last ring out, even more water will come in, but it's not as bad as you think it will be. Use a small flat blade screwdriver to scrape the internal face of the gland scrupulously clean, as this mating surface provides the majority of the seal.

Push the first new ring home - you can use the gland insert thing to help push it home. Add the second ring, making sure the cut is 180 degrees around from the first ring - push home with the insert again. Repeat for the remaining rings.

Push the insert in, and tighten it up until the gland just stops dripping. Run the boat for an hour to settle things down, then tighten the gland until you get 1-2 drips a minute whilst in gear - don't overtighten or attempt to get a dripless seal, as you can overheat the gland and bugger the shaft.

It's really not a difficult job, but it can be a bit fiddly due to the access. It can also be a bit awkward getting the new rings in as they will be a reasonably tight fit - trick is to just get it started all round then use the insert to push it home fully.

Best of luck - I've done my P385 and a friends F43 both afloat and it isn't scary!

If at any point you get worried, just push the insert back in to stem the flow and have a stretch and a five minute break.

 

[chesapeake]

Thank you Ross for your comprehensive explanation I feel more confident about attempting it now.