OB1 below the waterline?

[JFowler]

I plan to replace some of my below waterline Seacocks. My ‘stock’ sealant is OB1- is this ok or should I splash out on Sika 291i ?

 

[jwilson]

I have used OB1 on several seacocks, including one that urgently had to be replaced whilst the boat was in the water - engine intake seacock that whilst the handle turned, the ball stayed closed. Despite fitting the new seacock into a substantial spout of incoming seawater, it has stayed sealed fine several years now. At the time I thought it might hold things till I got a liftout, but it just worked as well as the other seacocks and skin fittings I used OB1 for whilst ashore, so I've left it.

Personally I prefer CT1, but OB1 is much more readily available locally, and it seems just about as good.

 

[wiggy]

I used CT1 on all my new seacock, basically the same stuff as OB1.

 

[JFowler]

Just to be clear I propose using OB1 to seal new skin fittings to the hull as well as the seacocks.

 

[jwilson]

Just to be clear I propose using OB1 to seal new skin fittings to the hull as well as the seacocks.

That's what I used when I fitted all new skin fittings and seacocks some years ago.

 

[PaulRainbow]

I plan to replace some of my below waterline Seacocks. My ‘stock’ sealant is OB1- is this ok or should I splash out on Sika 291i ?

I routinely use it for depth transducers etc. no issues at all.

 

[JFowler]

Thanks all - I’m suitable reassured!

 

[jamie N]

CT1 is stocked at my 'local' Toolstation.
Wonderful stuff....