Re: Packing material for water cooled prop shafts
Posted: Mon Jul 20, 2009 5:58 pm
and its called PPE !!
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Packing material for water cooled prop shafts
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Re: Packing material for water cooled prop shafts
Posted: Mon Jul 20, 2009 6:10 pm
Re: Packing material for water cooled prop shafts
Posted: Mon Jul 20, 2009 6:55 pm
h
Nah, you're reading the tag's reflection in a mirror. It is actually a dd (extra)conrod wrote:and its called PPE !!
Re: Packing material for water cooled prop shafts
Posted: Tue Jul 21, 2009 3:01 am
Hey, it would be good for productivity too..with a cup that big you could store your lunch in there and never leave the workplace. Those crafty Chinese.
Re: Packing material for water cooled prop shafts
Posted: Sun Aug 02, 2009 12:31 am
Probably any natural fibre coated in Tallow will do, I don't think it does any harm to give the packing a liberal coating of grease when you fit it either.
Obvious key points for anyone not used to this old type of seal is that the shaft should be polished as smooth as possible so it does not shred the packing, and the gland should be tightened up very slowly with the shaft turning, never tighten the packing so that the flow of water is completely stopped.
A small leak of water is required to cool and lubricate the packing, while the shaft is running. It is possible to tighten the gland up enough to stop the water flow while in Port ( to reduce the amount of bilge water you have to dispose of) but essential to slack the gland back again before the engines are started. This was normal practice on the cargo ships I sailed on in the 70's.
Often the nuts and studs on the glands are heavily corroded, they should be Bronze but even so, over the years...
It is well worth investing the time and effort to clean up all the threads, and grease them well, it makes it much easier to adjust the gland and therefore more likely that the gland will be kept correctly adjusted.
Some Teflon coated packings are supposed to be suitable for packing slow speed shafts, but they are very prone to overheating and burning if over tightened, (they smell horrible) I wouldn't reccommend them to anyone who has not already gained experience with the traditional packings..
Big Pete
Obvious key points for anyone not used to this old type of seal is that the shaft should be polished as smooth as possible so it does not shred the packing, and the gland should be tightened up very slowly with the shaft turning, never tighten the packing so that the flow of water is completely stopped.
A small leak of water is required to cool and lubricate the packing, while the shaft is running. It is possible to tighten the gland up enough to stop the water flow while in Port ( to reduce the amount of bilge water you have to dispose of) but essential to slack the gland back again before the engines are started. This was normal practice on the cargo ships I sailed on in the 70's.
Often the nuts and studs on the glands are heavily corroded, they should be Bronze but even so, over the years...
It is well worth investing the time and effort to clean up all the threads, and grease them well, it makes it much easier to adjust the gland and therefore more likely that the gland will be kept correctly adjusted.
Some Teflon coated packings are supposed to be suitable for packing slow speed shafts, but they are very prone to overheating and burning if over tightened, (they smell horrible) I wouldn't reccommend them to anyone who has not already gained experience with the traditional packings..
Big Pete