Is it a good idea to pour rust inhibitor into keel bolts via the bilge?

[StickyJimmy]

We have some rust weeping from the Keel hull joint as shown:



The red paint is my attempts last season to treat surface rust using a red owatrol oil rust inhibitor paint for metals.

Sometimes water oozes out of the joint (as seen), and sometimes in between visits to the boat water collects in the bilge.

It is my concern that this water is originating from the bilge and that the keel hull joint is compromised and allowing water to intrude to the bolts and potentially up to the bilge.

Since I do not wish to drop the keel at this time, is it an idea to pour a bit of Owatrol oil (https://owatrol-international.com/en...atrol-oil.html) into the keel bolt holes from the bilge with the intention of driving out any moisture and air as a means of stabilizing the keel bolts and keel surface from (lesser rate of) corrosion.

I will be tightening the keel bolts anyway and this would be one extra thing to do.

Thoughts?

[Manateeman]

You might fill the bilge with cement and drive a bolt or two into the keel.
Then you support new “floors” to the hull and or frames.
We have actually seen this done in Holland on a steel and a wood boat.
Old fishing boats are “saved” by this system.
Not our suggestion. Who are we to criticize other builders.
The manatee crew.

[JoetheCobbler]

Imo, a waste of time.
If the bolts are compromised, they're compromised.

[tkeithlu]

This situation cries for further exploration. As Joe implies, you don't know the condition of your keelbolts, only that they are corroding and that there is enough space around them for oil (and seawater) to intrude. The exposure may be both from water in the bilge and from water coming up from the gap at the keel. I gather that you have access to the nuts.

I recommend that while you have her on the hard you lower the keel a short distance, within the amount you can loosen the nuts without actually dropping the keel. Inspect it and dry it out. Then you are in a position to fill the gaps, both along the bolts and in the crack, with the water-excluding goo of your choice. You can take the nuts off one at a time to get better access.

Alternatively, and I hope that it is not this case, you will find that the bolts are seriously compromised. Still, better to find that out on the hard rather than when your keel breaks off during a storm.

Good luck with it.

[Bowdrie]

In the product description it specifically states that the product is not compatible with 2-part paints.
Based on that, (and without further info from maker,) I would assume that Polyester, and/or Epoxy resin products would also not be compatible.
I would never apply/use a product on a fiberglass surface/component that would preclude later adherence of an epoxy unless it was easy/painless to remove.

[Lake-Effect]

I would not be pouring any oil/grease product into any part of a boat (besides the engine ). The oil will interfere with future painting or repairs.

Best idea is to follow the good advice already given re carefully inspecting your keel bolts. At a minimum, if you can dry out that joint, you could attempt to patch, seal or barrier-coat the area, but the problem will likely return later if you don't do a more complete sealing job.

[Cheechako]

If you are not going to pull the keel and fix it properly, then I would say just leave it for now. A band aid is not going to help.

[Bill O]

Rust is a constant issue w/iron keels.

Once rust starts it continues to form even if you barrier coat it. Been there, done that attempt that everyone tells you to do. Time consuming and relatively expensive for the few years it hides it. The fact is no one sees your keel unless its on the hard.

Dropping the keel and re-bedding would be the best approach since the rust expands the joint allowing water in. If water is still in the joint and the boat is on the hard, the water may freeze and also expand the joint.

If you do not want to drop the keel, a good stop gap would be to grind out the joint to remove the majority of the rust and use 5200 to seal the joint. This "temporary" fix will usually last for years before it needs to be redone again.

Do not put oil in the bilge. You will regret it later when you want to paint or use any type of sealant in the bilge.

[RaymondR]

If there is already a layer of rust on the keel there is nothing you can do to stop further corrosion. Any sealing product you introduce will just sit on top of the layer of rust allowing moisture to continue to penetrate the rust layer and the corrosion process to continue.

However you may be able to slow down the corrosion by loosening the keel bolts and creating a gap through which you might be able to remove any loose rust. I suspect the best product to slow down the corrosion process might be pitch or tar if you can get it.