keel Bolts

[flyingskipper]

I have just antifouled my hull and whilst doing so i noticed the bolt heads under the keel are deteriating some what. Is it a good idea to replace them all in one go or a few each year? I have a funny feeling if i try to do them all in one she is going to be out of the water for quite while as i can only work on her at weekends. Perhaps someone would let me know the best way to do them.
Thanks.

 

[fisherman]

Normal procedure is to draw one and have a look. If they are bad they will twist off, the middle will be needle thin, and you have to drive out the remains with a hollow nosed punch. There is some debate on the best material for the replacements.

 

[pirate]

just doing the keel bolts on a 70 year old hillyard.out of the 11 bolts 2 just drifted out using a lump hammer and steel drift.the others as fisherman says simply twisted to a point in the middle of the bolt.then made a long drift with a countersunk hole on one end that went over the point and then hit them with a sledge hammer which might sound over the top but allows a lot more control than wielding a small hammer.one was seized solid and took 2 days and making a puller to move.depends how old your bolt is.i would pull out the easiest one and see how it is.if its bad then you will have to bite the bullet , get new ones made and go for.it.
does anyone know why you should use wrought iron for the bolts and not mild steel.i was advised to make them out of mild steel so i made 5 and have now been told this is no good!!!!!!!!!!!!!!

 

[bjames1955]

I replaced about 15 some 6 years ago. wanted to go for bronze but couldnt afford it, got cajolled into getting them made in mild steel and already have a couple of iffy ones. Go with the best you can afford!

 

[srp]

Steel is an alloy (of iron and carbon). Most alloys are more prone to corrosion than pure metals. Wrought iron is fairly pure (although it does contain carbon it is not alloyed, the carbon is in it's free form). I would think that wrought iron is very difficult to come by now (unless you know differently). If I had to have steel keel bolts I would get them galvanised personally.
I've actually got 3 new unmachined bronze ones sitting in my garage (an embarrassing error some years ago) that really ought to go to a good home.....

 

[Transcur]

I think you can get wrought iron from stourbridge or here. www.realwroughtiron.com/

A good source is fron old buildings being demolished. Tie bars are usually wrought iron. A trip to the scrap yard may be worthwhile. I picked up over 40ft of 3/4 inch wrought from a local roadside skip. Cost --nothing, even got wrought nuts as well.

 

[airborne1]

I have been told by the guy who has just sold me my 1949 built yacht that the keel bolts are Gunmetal. Surely they cant be the original bolts.
Anyone ever heard of this metal being used??

 

[Mirelle]

Gunmetal is perfectly possible - if the keel is lead. However, they do deteriorate slowly and it would be worth pulling one.

 

[cliffordpope]

The correct metal to use depends on what the ballast keel is made of. For a lead keel, bronze is correct. For a cast iron keel, the bolts should be wrought iron. The choice depends on minimising electrolitic corrosion between two dissimilar metals. So neither is "better" absolutely, it depends on the keel.
But I'd have thought mild steel would corrode very rapidly. I suppose that would be OK if you pulled out the bolts each year. Ordinary wrought iron is obtainable. The absolute best is marine grade wrought iron, or so I was told by Coventry Boatbuilders some years ago. It is not made now, so is only obtainable when an old boat is scrapped. Having got the iron, you then need a competent smith to make it into bolts of the right diameter.
Finally remember that iron will attack oak in the presence of seawater, so you traditionally place tarred canvas between the wooden keel (if oak) and the iron ballast keel.

 

[Mirelle]

I got the last lot from http://www.realwroughtiron.com/

Prices were very reasonable, I thought. These bolts replaced mild steel ones put in in 1985, which needed renewal by 2001. Bolt diameter is 1.25", keel is teak and ballast keel is cast iron.

 

[fisherman]

[ QUOTE ]
There is some debate on the best material for the replacements.

[/ QUOTE ]

See?

 

[flyingskipper]

This is great feed back thankyou. I will go for iron bolts as the keel is of cast iron, well greased and calked at the bottom. I can imagine the hard work is removing the old ones, I like the idea of making a punch out of a bolt to drive out the old ones. Again thakyou everyone for your advise.
Andrew.