Suitable Sealants for Keel Bolts?

[Ship'sCat]

The keel bolts connecting my 1968 GRP hull to the cast iron key are secured with a square steel plate about 50x50mm located beneath like washers beneath each bolt's nut in the bilges. The idea I guess is for the steel plate to spread the load on the grp. These large plates seem to be bedded on a generous bedding of Hermetite Red, a recent discontinued product used to make gaskets in motorcycle cylinder heads! I recognise it from my bike days. Does anyone have a similar experience spotting car gasket material being used to seal yacht hulls? The Hermetite seems to have worked for many many years in this instance.
Can anyone suggest a suitable modern non-setting alternative? I have looked at Sikaflex 591 but the manufacturers say it is suitable just for experienced professionals to use.

 

[burgundyben]

I reckon that's red lead paste not red hermetite.

I have had great success with Arbomast BR, used it on hull fitting underwater and it's been fine long term.

 

[Ship'sCat]

I reckon that's red lead paste not red hermetite.

I have had great success with Arbomast BR, used it on hull fitting underwater and it's been fine long term.

Thanks for this. Maybe Hermetite is similar to red lead paste? The sweet smell is very familiar, and the bedding of whatever it is is crumbly. I might just replace it all with Arbomast BR or similar then, or else make up neoprene gaskets from old 5mm wetsuits.

 

[Graham376]

Keel stud washers are often bedded on a donut of caulking cotton without any other sealant.

 

[guardian]

Sabatack 750 / 750XL

 

[Ship'sCat]

Keel stud washers are often bedded on a donut of caulking cotton without any other sealant.

Even on fibreglass boats?

 

[PhillM]

If it is read lead paste, why not replace with same :

https://www.traditionalboatsupplies.com/33-leadbasedproducts

 

[matthewriches]

We've just put a Southerly back together with Arbokol.

 

[Graham376]

Even on fibreglass boats?

Yes. My Centaur and Berwick used that method and the surveyor specified the same for my M346 when I changed the keel studs. There's an article here and I see they advise using sealant as well as caulking. http://www.craigmarine.info/boating/Curing-leaking-bolts.htm

 

[Ship'sCat]

Thanks, that's a great reference. But did your surveyor also specify the red lead paste as well as the caulking cotton?

 

[Graham376]

Thanks, that's a great reference. But did your surveyor also specify the red lead paste as well as the caulking cotton?

No, I never heard of using red lead paste until this thread, can't remember what I used under the plates except for the caulking cotton, it was many moons ago