Nauticat 331 Stern Gland Adjustment

[John Crump]

Does anyone have a pair of open-ended 70 mm A/F spanners needed to adjust the stern gland on a 331?

[Chris Lawrence]

Good morning. We have a 15 year old 331. We have had a nasty experience after the boatyard repacked the stern gland 5 engine hours ago. The rubber gaiter came off the rear Fiberglass tube and water started to flood in. Fortunately the bilge coped and we reattached the gaiter with 3 , rather than the one, jubilee clips used by the boatyard. My query is that the gaiter looks very short for the space between the stern nut assembly and the bulkhead where the tube is sited. Is there a set length for the rubber? Should it completely fill the intervening space? Thanks. Chris

[Chris Lawrence]

Here’s a picture of our stern assembly.

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[Chris Lawrence]

And this was it when it leaked a few days ago.

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[John Crump]

Chris,
That looks the same as the arrangement I had in SKYLER. The length of the gaiter should be OK and you have double clips on each side. But were the clips properly tightened? If not, then the joint could well have been broken through twisting when your mechanic used spanners to slacken and then re-tighten the gland nuts.

[Chris Lawrence]

Thanks for that John. What exactly do you mean by ‘broken through’? There was a fair bit of grease at the joint. Would this be a factor?
Chris

[John Crump]

Chris, The rubber needs to be only long enough to provide watertight joints at both the stern tube and the gland ends. The position of the stern gland is dictated by the length of the rubber and needs to well clear of the gearbox coupling. By “broken through” I meant that, when slackening or tightening the gland nut and its lock nut, it is relatively easy to apply a twisting force (torque) to the rubber tube. If the jubilee clips were not sufficiently tight, that torque could have broken the watertight grip of the rubber on either the gland or the stern tube. I assume that you have checked that the rubber itself is not damaged? There will inevitably be grease everywhere since you are injecting it under pressure from the greaser!

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