Below water line sealant

PabloPicasso

PabloPicasso

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I have found an ouzing water leak from a bolt that holds the rudder bearing plate onto the Skeg. I'm obviously going to dry the boat out on the hard standing and reseal. But what is the best sealant. Over heard sikaflex is not great underwater. Tek7 perhaps?

I'd value feedback on this issue at this point as I'm going to have to decide soon. Many thanks
 
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I had a minute weep from a rudder bolt. When the boat was ashore I loosened and removed the nut and smothered the thread and into the hole gap around the bolt Captain Tolleys leak seal. Goes in like milk then dries clear. Repeated thus several times over a few days, until the crack would accept no more. Re applied the nut and washer, no more weep. Still good after 2 seasons.

A thicker sealant will only work if bedded in. Simply smearing over won't work. I use Sikafkex 291, but the 3M range are good. If you can get a Polysulphide sealant this would be ideal.
 
PabloPicasso said:
I have found an ouzing water leak from a bolt that holds the rudder bearing plate onto the Skeg. I'm obviously going to dry the boat out on the hard standing and reseal. But what is the best sealant. Over heard sikaflex is not great underwater. Tek7 perhaps?
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Tek 7 will be fine. It supposed to be able to be applied under water so why not dig out the wetsuit...;)

Seriously though, Tek 7 is well proven and suited to the job so I'd go for that. Regarding sikaflex, I've used sikaflex for underwater fittings for years and never had any problems. Its one of those "You pays your money" choices...
 
saxonpirate said:
Tek 7 will be fine. It supposed to be able to be applied under water so why not dig out the wetsuit...;)

Seriously though, Tek 7 is well proven and suited to the job so I'd go for that. Regarding sikaflex, I've used sikaflex for underwater fittings for years and never had any problems. Its one of those "You pays your money" choices...
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Do you think sikaflex is better underwater than trek 7?
 
PabloPicasso said:
Do you think sikaflex is better underwater than trek 7?
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As I said, I've used Sikaflex (normally 221) for underwater fittings for years without problems. Have used it to bed cast keels to hull joints so.. To be honest, I don't know where a lot of these rumours about certain sealants start from. Usual yacht club chatter I guess after a few G&T's. Is Tek 7 any better than sikaflex? I've never read a scientific study (if there is one). If you are trying to seal an area that may still be wet though and the sealant is liable to displace water I'd use Tek 7. I say that because I've always applied Sikaflex on dry substrates.
 
saxonpirate said:
As I said, I've used Sikaflex (normally 221) for underwater fittings for years without problems. Have used it to bed cast keels to hull joints so.. To be honest, I don't know where a lot of these rumours about certain sealants start from. Usual yacht club chatter I guess after a few G&T's. Is Tek 7 any better than sikaflex? I've never read a scientific study (if there is one). If you are trying to seal an area that may still be wet though and the sealant is liable to displace water I'd use Tek 7. I say that because I've always applied Sikaflex on dry substrates.
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Ok I have some tek7 already. Area is wet at the moment as it has been leaking a little. So if I dry out between tides it'll be tek7. If I can get a crane lift out, preferred for this type of 'it can go wrong' job, I will have a choice if I can dry her out properly.

I think it may be preferable to apply sealant to dry surfaces anyway, gently tighten down. Then leave for 24 hours for sealant to cure and tighten down fully.

But that would be dependent on getting a crane lift.
As always, thanks for the replies
 
philip_stevens said:
Try CT1. Read the post below - http://www.ybw.com/forums/showthread.php?362541-CT1 - it works on wet surfaces. They once had a video that showed a plastic cup oozing with water from a split, being sealed while water was escaping.
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I have been using CT1 for a couple of years now on the boat and found it very good, on our last boat I used it to seal new bolts I had fitted to the rudder and it worked very well and the bonus is you can clean it of your hands or surfaces and it will last for months once opened.
 
Ok. I used Tek7 (similar I believe to Ct1). And actually half the price of sick a flex. After 6 hours when the tide came back all was dry. So far a big thumbs up for tek7. I'll see how durable it is as I sail this weekend.
 
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