Fitting a hull anode

[vyv_cox]

Ah I do have one of those yes thats a good idea.

Quite honestly it isn't worth the effort. If the nuts are so corroded on the stud then the chances are that the whole lot needs to be replaced anyway. I would undo the nuts from inside the boat and knock the studs through. Assuming they are the correct ones as in VicS' drawing. Studs are reasonably cheap and you will then know that all is well.

 

[jac]

Quite honestly it isn't worth the effort. If the nuts are so corroded on the stud then the chances are that the whole lot needs to be replaced anyway. I would undo the nuts from inside the boat and knock the studs through. Assuming they are the correct ones as in VicS' drawing. Studs are reasonably cheap and you will then know that all is well.

If one is going to do that, is there much likelihood of needing to repair the hull where the old studs were or would it normally be a case of new studs, plenty of favourite sealant and then slap anode on?

 

[eddystone]

Quite honestly it isn't worth the effort. If the nuts are so corroded on the stud then the chances are that the whole lot needs to be replaced anyway. I would undo the nuts from inside the boat and knock the studs through. Assuming they are the correct ones as in VicS' drawing. Studs are reasonably cheap and you will then know that all is well.

Sounds a good plan - is Sikaflex 291 the right stuff for sealing the bolt through the hull opening?

Also, seem to remember the nuts inside the boat were also smeared with something - I guess Vaseline rather than grease.

 

[vyv_cox]

I use Sikaflex 291 for pretty much every sealing job above and below the water, unless I have some Puraflex 40 at half the price. With a little bit of care, rather than a big hammer, the bolts will cut through the sealant quite easily, so no hull damage.

 

[single]

Yes. The new anode should come complete with two new nuts with star washers to hold them and a plastic backing pad to insulate the anode from the hull. All the new components should be used to replace the old ones. If the nuts are seized on to the stud I would use a nut splitter rather than getting too enthusiastic with anything else otherwise you could turn the studs and damage the seal, giving yourself more work.

I still don't understand the need for a backing pad?

 

[vyv_cox]

I still don't understand the need for a backing pad?

I have never been sure of its function. The last one I bought, before I removed the anode altogether, had a foam rubber/plastic gasket-like pad with it. I cannot see it being an insulator being saturated with water. It's the grey/black thing in VicS' diagram.

 

[VicS]

I still don't understand the need for a backing pad?

To protect GRP hulls and painted surfaces from damage

The prevent alkaline delignification of wooden hulls

The prevent corrosion of the backs of anodes especially on steel hulls.