Keel bolts - brown sludge

[Ldh]

I'm hoping someone can tell me whether there is a problem with these bolts /keel or whether they just need a clean? Pictures attached.hunter legend 1993.
Many thanks lee

[captain465]

Looks like they may have been coated with something.
Take some acetone and clean them. If that is insufficient, a stainless steel wire brush will clean them up enough for close inspection. If no obvious wastage, re-coat with a waxy covering.

[GordMay]

Greetings and welcome aboard the CF, Ldh.

[Calif.Ted]

The trouble area is down below where you can't see, the parts in the bilge can be nice and shiny but eaten away in the keel stub area. The brown sludge is troubling because it indicates rust or rot from that area, beyond the indication of a water leak at that bolt.

[Nicholson58]

Ted is correct. If your keel has never been dropped the sealant between the stub and lead probably leaks. This makes an oxygen depleted zone. This is potentially bad for the keel bolts. The proper job is to drop the keel, clean the entire area, inspect the bolts. Let’s assume bolts are OK. Re-bed the entire thing and re-attach with new sealant. If you are n doubt on the need, ask a surveyor or other qualified mechanic. Not a big hurry, schedule at a convenient Hal out.

[ferrailleur]

Originally Posted by captain465

Looks like they may have been coated with something.
Take some acetone and clean them. If that is insufficient, a stainless steel wire brush will clean them up enough for close inspection. If no obvious wastage, re-coat with a waxy covering.

Why a stainless steel wire brush?
Thanks

[stormalong]

Originally Posted by Nicholson58

Ted is correct. If your keel has never been dropped the sealant between the stub and lead probably leaks. This makes an oxygen depleted zone. This is potentially bad for the keel bolts. The proper job is to drop the keel, clean the entire area, inspect the bolts. Let’s assume bolts are OK. Re-bed the entire thing and re-attach with new sealant. If you are n doubt on the need, ask a surveyor or other qualified mechanic. Not a big hurry, schedule at a convenient Hal out.

Crevice corrosion can be very hard to see. The only way to tell for sure is dye penetrant testing the bolts which means removing them from the keel. I don't know how well that would work on threaded bolts. If you are going to drop the keel I suggest that you just replace the bolts. Not knowing how they are set into the keel it may be time to consult a professional.

[George DuBose]

I have to thank Pearson for using bronze "J" bolts on my P36. Someone, a PO probably, poured resin all over the keel bolts, to stop leaks, I suppose.

This prevented me from dropping the lead part of the keel so I could rebed it. I can only keep the seam closed.

I tried to use a core saw slipped over the keel bolt, but whenever I stopped turning the core saw, it froze in the resin.

At least I know the lead isn't going to fall off...

[Ldh]

Thanks for all the great replies. I'm still confused as to the cause though. Someone who looked at it also thought it was a special grease (as mentioned above) but to my eye it looked like something coming from under he bolts (also mentioned above). Obviously i'd like it to be grease, but i'm not aware of special grease that one would put on them.

[donradcliffe]

The bolts don't look too bad. What is scary is the small washers used instead of backing plates.

[mike d.]

It looks like sludge ! Like from engine oil that was floating in the bilge water ! Some of the sump edges show signs as well ! That may be what is oozing out from under the washers ?

[Michael Pope]

I would guess that it is part and parcel of the sealant used when the keel was installed last. On production boats one usually covers the whole of the area of the top surface of the keel with one of the sealants ( there are hundreds of them) and if you are careful you will sand the bottom of the FRP hull and then wash it with alcohol , Wash the bolts and nuts with soap and water , dry them and wash them with alcohol as well. Then you coat the bolts and thread them into the Ballast , re-coat them and fill the holes then install the keel . Many
production boats drill the keel and the hull bottom with the same two sided Jig
so there is some slop or clearance. The excess sealant will squish out around the bolt and washer . There are many variants of Thiokol Patent based Rubber or lower tensile strength sealants used . Some old hands at this game have had bad experience with excessively strong (in Tensile) sealants which would not allow you to detach the keel without near Fatal Surgery.
I would not worry about the staining 10 to one it is just what has grown in the bilge if the boat is more than five years old, from sawdust house type dust etc If you are worried build a form ahead of and aft of the keel and lower the boat into it and try levering or gently jacking the bottom of the keel athwartships less than two inches first one side then the other and closely monitor the seam where the Hull meets Keel . If it smiles and says hello you have trouble. Drop the keel and replace all the bolts with custom made MONEL bolts and nuts. The only way to go. Monel is too expensive for many builders but just the right price for a good nights sleep Michael Pope

[Nicholson58]

Originally Posted by ferrailleur

Why a stainless steel wire brush?
Thanks

Use anything but steel. Steel wire leaves residue and bits of steel to corrode. SS, brass, etc. same idea, use brass wool, not steel wool.

[stormalong]

Originally Posted by donradcliffe

The bolts don't look too bad. What is scary is the small washers used instead of backing plates.

With Crevice corrosion the bolts do not have to look bad to be bad.

How old is the boat?

Is the original builder still around to ask how the bolts are set in the keel?

If the bolts are just turned into the keel it would be worthwhile to extract them and replace them. If they are J bolts cast into the keel I do not know what you would need to do to replace them which is why I suggested that you ask a professional.

+1 on monel bolts. My boat was built with monel bolts and after 35 years they look like new. 35 years ago monel wasn't as much as of a price premium that it is today.

[Michael Pope]

How often I say this now-- IN THE OLD DAYS Keels were a lot fatter and not as deep and the casting systems not as perfected . So you used "Pocket Bolts"

You cut a pocket some 8" to 10 " down from the top Made the top face of the hole flat and horizontal and put a good thick plate in their preferably Monel or Bronze if you were using Bronze bolts. You climbed up into the boat and with your heart in your mouth drilled down thru the Keelson or keel aiming for the centre of the plate . When you had a good secure centre mark you took the plate out, marked it front and back ,and drilled the hole thru on the drill press.
You then drove the bolt thru cleaned the thread and put a double nut on it.
Center punched the the nuts
If you were smart you built a little little shute and face out of tin and a face plate for the other side , if the hole went all the way thru the keel. You then melted some lead and filled the hole up till the lead poured out the little vent holes you left at the top. Wait for it to cool and cut off the shute and put some filler in the cracks. And "Oh yes Boss hit it dead centre " Young Eyes you know" Phew! You did all the bolts . Then hopefully the Hull will lift enough with some persuasion to let you caulk and fill the Faces and bolt it up. Next morning some sharp eyed young architect would take one look from 100 feet away and say "Keel is on crooked " "Two degrees to port" It had been 1:30 AM when you bolted it up. It was dark. Oh the good old Days !!!??? MP