GRP Leak - Forum

Candanski
Advanced Member Topic Starter

2012-05-11T13:54:30Z

I have a nasty leak in the narrow space below the propshaft on the starboard side where the side meets the bottom and about two inches from the rear vertical. I have been assuming the water ingress was due to a leaking stern gland but I have just cleaned off the grease left by the engineer who repacked the stern gland. Water is seeping out of a point on the GRP at the rate of about one large drop per second. I cant understand why this would have started happening. I considered it may be something to do with the conversion from tiller to wheel. I am on a drying mooring. How can I trace the external source of the leak.Can anyone advise ... Please

Mike Edwards
Advanced Member

2012-05-12T17:49:35Z

#2

Hi Candanski

I am having difficulty visualising where the leak is.

Is there any chance you can take a photograph showing the location and a close up of the leak. You could draw on the photo to indicate where the leak is.

Thanks

Mike

Mike Edwards

Seal 28 "Aztec"

Mike Edwards

Seal 28 "Aztec"

Candanski
Advanced Member Topic Starter

2012-05-13T12:11:50Z

#3

I don't have a camera available at the moment unfortunately. Due to the proximity to the prop shaft and the fact that I just had my stern gland packed by an engineer who used a a hammer quite liberally I think the water is most likely entering in this area possibly via a damaged seal. But I cant visualise where, as I dont really understand the whole cutless bearing/stern gland assembly. Could someone please post a diagram of the prop shaft as it passes through the hull showing the stern gland and cutless bearings and how they fit together.

Thanks

Mike Edwards
Advanced Member

2012-05-13T13:23:55Z

#4

Hi Candanski

There is a basic drawing here

http://www.swatchway.pwp...jects/aztec-projects.htm

The inner bearing and the outer bearing housings should be joined together with a tube which is screwed into the housings. Depending on what your mechanic has been wacking with a hammer the outer bearing housing may have been dislodged and the housing/hull joint is leaking.

The outer bearing housing on Aztec is held with 2 bolts and when these are removed the outer bearing housing can be turned (I use a little heat and a pair of stilsons) to unscrew it from the shaft. Once this is removed you may see water run out if the joint has been damaged. If you do remove it you may as well fit a new cutless as well.

I refit everything after cleaning well, with lots of sikaflex. I only tighten the housing to within half a turn of being flush with the glass fiber and this leaves a nice little gasget of sikaflex. I put the bolts in loose and then take them out again and clean the threads, I leave this to cure and after a few days I put the bolts back with grease on the threads and sikaflex on the bolt shank and under the hex head.

Mike Edwards

Seal 28 "Aztec"

Mike Edwards

Seal 28 "Aztec"

Candanski
Advanced Member Topic Starter

2012-05-18T09:37:47Z

#5

Mike Thanks for posting and the diagram link, I was called away to Scilly for the week and didn't have internet. I have temporarily stopped the leak with sikaflex on the outside of the cutless. I think my set up may be slightly different to yours. in that I think the stern gland is fixed directly to the stern tube I think the stern gland flange has been glassed over to make a seal. and after being whacked by the hammer the water has leeched between the original gelcoat and the stern gland glassing about six inches away from the joint. But it is so difficult to be sure. I was hoping i could get this fixed when she dries out on the mooring. But I think i may have to take her right out to get this fixed.

Thanks again for replying this is really worrying me.

Regards David

Mike Edwards
Advanced Member

2012-05-18T12:26:33Z

#6

Hi David

I believe it is the outer bearing housing to hull joint you should be looking to try and seal.

In my view where someone has glassed over the inner bearing housing they may have just allowed the sea to flood into the fabric of the boat.

Having said that there are some stern tubes which were just glassed into the boat you may have one of those.

I would recommend taking the boat out of the water to do this job. Jobs like this can take longer than you first think.

Good luck, let me know how it ends.

Mike

Mike Edwards

Seal 28 "Aztec"

Mike Edwards

Seal 28 "Aztec"

Candanski
Advanced Member Topic Starter

2012-05-27T12:36:29Z

#7

Mike

you were spot on with your diagnosis. I took the boat to the top of a slip just after high tide and did the job in under an hour. I now have a dry bilge for the first time ever.

Thanks so much for your advice.

Regards

David

Mike Edwards
Advanced Member

2012-05-27T16:40:28Z

#8

Thats good news

Mike

Mike Edwards

Seal 28 "Aztec"

Mike Edwards

Seal 28 "Aztec"