Stern Gland Struggles

[Rabbit]

Hi Everyone, I am still researching the repacement of my MK3 stern gland. Has anyone replaced one with the offset propeller shaft. If so any gained ideas to make the job go a little easier would be much appreciated. The yacht is powered by a BMW D12. It has a oil filled mechanical type seal arrangement stern gland. I plan on replacing it with a stuffing box type. Anyone purchased this type and do you have any dimensions I can give to porters.

[Dolphin]

G'Day Rabbit,
I replaced the D12 with a Volvo. Well, I had it replaced more correctly.
THe stern gland was removed by Tony Clapson Marine at Burraneer Bay. There is a cutlass bearing at the hull and one at the skeg. THis means the shaft has no where to move as the engine jumps around.
The cutlass bearing was removed as the stern tube to fibreglass seal was leaking. It is now just a stern tube.
Volvo have a rubber gland that is in the form of a boot. They reckon that it will last 5 years before replacement, then it has to be done on a scheduled basis before it fails. It is lubricated with waterprof grease and EVERY time the boat goes back in the water you have to remember to squeeze the boot so the water runs in through the seal to lubricate it.
I would very happily replace the stuffing box or the rubber seal with an oil filled gland any day. That gland didn't ever fail. Tony replaced the bearings. There 3 bearing in there I think. I wouldn't throw it out.
If you want to get rid of it let me know.

[Dolphin]

G'Day again Rabbit,
I was at LMYC today tuning an Endeavour 26, The boat next to us was getting a Yanmar serviced. The mechanic there didn't have any special recommendations but he said that the stuffing box is a problem to get just right and it takes a bit of experience to stop it leaking and getting it to run right.
Another complication. Hope it helps.
Greg.

[Tales]

The normal lubrication for a stuffing box type of seal in a water environment is water.

For the water to do it's job is has to flow through the stuffing gland. Only a few drops per minute are necessary but if there is none the sealing material will overheat and usually damages the shaft.

Naturally on a boat that will mean bilge water which is why other types of seals have been developed over the years.

Cheers,

Tom

Update - see http://wwwsailboat2adventurecom.blogspo ... gland.html

[Rabbit]

Thanks for your comments on stern gland replacement. With the BMW D12 fitted I was unable to replace mine with a PSS type gland or the more common large nut with packing type gland because of limited room between the gland and the coupling, 13mm to be exact. This led to rebuilding the original oil filled gland with new bushes and seals. To make the change out without removing the engine I made an access hole under the quarter berth adjacent the gland. Rabbit

[Dolphin]

G'Day Rabbit.
Access to the stern gland on most Top Hats, or any boat for that matter is often restricted.
Fortunately, the previous owner had the foresight to cut a hole in the cockpit and put a hatch that gives good access. It was actually used to install the wheel steering.

Here is the Volvo installation that replaced the D12.
Wish I had have kept that diesel.

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The access is so good that on rainy days I'll take a good book down there and put my feet up.