Water cooled prop shaft!!!!

[Mike k]

Hi
does anyone know how the system works and how to check its functionality- I see a fitting which looks to go through the hull with a red turn on/off valve handle but no pump and cannot tell if any water is passing as the pipe is opaque! The pipe goes from the hull to the propellor housing.Its an inboard shaft driven set up.

Any pointers gratefully recieved.

Many thanks

Mike

 

[andy59]

Hi mike , does it look like this

I have only just aquired mine so dont know much about them yet , but i do know that they are dripping and have been told thats what they do .

 

[Mike k]

yeah Andy similar but could do with knowing how its supposed to work- mines not dripping - at least you know theres water doing something!!

 

[andy59]

Ah , but on the positive side if its not dripping then your boat is not slowly sinking

 

[Tranona]

The drip from the stuffing box packing is normal as it relies on water to keep it cool. It can be adjusted by tightening the two nuts at the end (after slackening the lock nuts). The water feed is there to ensure there is always water in the stern tube. It can either be drawn from outside or with a positive feed from the engine cooling system.

 

[Mike k]

Tranona when you say drawn from the outside what is the mechanism of this - deos the rotation of the prop pull in the water. Also i thought tightening the 2 nuts for stern packing prevented water ingress from outside- are you saying there is a link with the water cooling side here?

 

[Tranona]

Have a look at the Vetus catalogue pages 40-44 www.vetus.com which explains how they work if you have one like Andy's photo. The actual sealing gland may be different as Vetus use lip seals which do not drip nor need adjusting. The one in the photo is called a stuffing box and the seal is a flax packing in rings around the shaft compressed with the tube at the end. These need to drip a little when running, but often if well adjusted do not drip when stationary.

Hope this helps

 

[volvopaul]

On most inboard engines the stern tube water feed is from the gearbox oil cooler, sometimes the union is in place of the anode on some volvo models(bad idea) so it sends water down the pipe to the sterngland on the outer side of the packing to cool the gland packing and cool the cutlass bearing in the sterntube.

You will get the odd drip thats quite normal, if water is leaking in without th shaft rotating and engine running you either need to tighten the 2 nuts evenly, if the water does not stop leaking in you need to change the packing in the gland, to do this sometimes the boat has to be lifted from the water, depends how brave you are and how many bilge pumps you have!

 

[Mike k]

Hey thanks for the brochure link- it looks like mine .I guess the scoop fitting shown on the outside of the hull draws water in at speed so i also guess that to check its working is to detach the pipe then travel and watch for water spurting out of the tube.Is that right???? Interestingly i had to adjust the nuts as a drip had started so even though the brochure says these dont need adjusting i am not so sure as it msut ghave some sort of gland packing ?

 

[davidej]

Hey thanks for the brochure link- it looks like mine .I guess the scoop fitting shown on the outside of the hull draws water in at speed so i also guess that to check its working is to detach the pipe then travel and watch for water spurting out of the tube.Is that right???? Interestingly i had to adjust the nuts as a drip had started so even though the brochure says these dont need adjusting i am not so sure as it msut ghave some sort of gland packing ?

Let me know when you are going to do this and I will call then lifeboat out!!

 

[Mike k]

tres drole!!- its a quarter inch pipe not the stern galnd pipe work"".So hope i wont need any lifeboat assistance!!

 

[Tranona]

Hey thanks for the brochure link- it looks like mine .I guess the scoop fitting shown on the outside of the hull draws water in at speed so i also guess that to check its working is to detach the pipe then travel and watch for water spurting out of the tube.Is that right???? Interestingly i had to adjust the nuts as a drip had started so even though the brochure says these dont need adjusting i am not so sure as it msut ghave some sort of gland packing ?

As I said, that is because Vetus use lip seals which do not need adjustment and do not leak, although they eventually wear and need replacement. Seems like you have a conventional packed stuffing box which can be adjusted, and when you run out of adjustment you can dismantle it and repack (out of the water of course!).

 

[aquatom]

Never had to lift a boat to repack the stern glands yet!

 

[DAKA]

Never had to lift a boat to repack the stern glands yet!

Kin'L , I wouldn't want mine to be the first