keel renovation

[MCL]

I have a small trailer sailor (Voyager 14) and I want to tidy up the bilge keels. I don't know if they are steel or iron is there a simple way to tell?
After removal I plan to clean them up either by getting a professional to shot-blast them or angle-grind them myself.

After cleaning how do I tell if the rust has effected the viability of the metal, can I take various measurements of the thickness to see if its deteriorated or is a visual inspection sufficient ? The boat is over 40 years old.

To seal them I don't know if I should use epoxy or possibly galvanize? The boat will be pulled up onto the trailer on the keels every time I go sailing so I don't know which will offer the best protection?

Finally I will replace the bolts with 316 grade Stainless steel, do I need to be aware of any interaction between the metal if the keel is cast iron?

thanks!

 

[alahol2]

Have a look at the bottom of this page... http://voyager14themightyatom.blogspot.co.uk/search?updated-max=2010-04-19T00:48:00-07:00&max-results=7&reverse-paginate=true

 

[VicS]

They appear to be fabricated from steel plate.

Angle grinding will probably remove too much metal. Grit blasting should remove only the rust and leave a surface suitable for a protective coating... the primer for which should be applied before any surface rusting can occur.

For a trailer-sailer a chemical rust remover followed by painting will probably be adequate

A simple paint coating will be easier than epoxy to repair/touch up if damaged.

If galvanising paint must be removed along with massive rust build up but the pickling process will remove surface rust.

Stainless steel is not a good fastening for steel due to galvanic corrosion but this will not be significant on a trailer-sailer.

 

[MCL]

They appear to be fabricated from steel plate.

Angle grinding will probably remove too much metal. Grit blasting should remove only the rust and leave a surface suitable for a protective coating... the primer for which should be applied before any surface rusting can occur.

For a trailer-sailer a chemical rust remover followed by painting will probably be adequate

A simple paint coating will be easier than epoxy to repair/touch up if damaged.

If galvanising paint must be removed along with massive rust build up but the pickling process will remove surface rust.

Stainless steel is not a good fastening for steel due to galvanic corrosion but this will not be significant on a trailer-sailer.

Out of interest how do you know they are plate steel and not iron? Many thanks for your advice

 

[William_H]

I am not sure that you need to go to all that trouble. Do you really think the keel bolts are liable to falure? Would it be easier to add some more new bolts than remove the keels and bolts. I have a snading disc rubber backing pad for my angle grinder which makes an ideal snader grinder for rust removal. It is highly unlikely you would have lost so much metal to rust or grinding as to be a concern. If the bottom edge is rough from rust then I would just clean up the bottom and lose a small amopunt of keell area and draft.
In other words I am advocating refurbish the keels in place and just treat with rust converter and paint with anti rust type paint. Don't get too carried away dismantling the boat it may not go back together again. (you might not find time)
Interesting looking at the blog in the link. I can see that channels in the trailer would be ideal for locating the boat on the trailer for transport. I think however that rollers of some sort set in the channels would make launch and recovery so much easier. If for instance he cut the channel and fitted a rollers just proud of the bottom of the channel so the keel sat on the rollers it would move so much easier. My Trailer sailer 21ft sits on rollers for the centre line and chine area and it will roll of the trailer on the ramp without being pushed and I can winch it up fairly easily with the trailer not emersed. So I don't know what OP has for the keels to sit on but he might find more benefit in improving the trailer.
good luck olewill

 

[MCL]

I am not sure that you need to go to all that trouble. Do you really think the keel bolts are liable to falure?

The bolts are unlikely to fail but I would like to remove the keels and reseal them too. Plus the boat is a bit of a project and I just want to give it a go!

 

[dartmoor]

I am the current owner of "the Mighty Atom" in the quoted blog from the previous owner! The keels are still rusty - but sound. I have got all the loose paint off, ground off the worst of the rust and treated the remainder. I plan to use an epoxy chassis paint from "rustbuster" once the temperature has risen a bit. Painting steel at this time of year, even under cover, is not great as the steel temp will not be far off the dew point, so paint curing and adhesion may be an issue. Just need a few days above 10 degrees! I am not inclined to dismantle the keels even though a thorough job might suggest I should. I would rather adopt the "Forth Road Bridge" approach, and keep re-treating and painting it every year as required. Still seems to be loads of steel there, so a few years left in it I guess, and the bolts and seals haven't caused any problems.

 

[Bosun Higgs]

I have a small trailer sailor (Voyager 14) and I want to tidy up the bilge keels. I don't know if they are steel or iron is there a simple way to tell?
After removal I plan to clean them up either by getting a professional to shot-blast them or angle-grind them myself.

After cleaning how do I tell if the rust has effected the viability of the metal, can I take various measurements of the thickness to see if its deteriorated or is a visual inspection sufficient ? The boat is over 40 years old.

To seal them I don't know if I should use epoxy or possibly galvanize? The boat will be pulled up onto the trailer on the keels every time I go sailing so I don't know which will offer the best protection?

Finally I will replace the bolts with 316 grade Stainless steel, do I need to be aware of any interaction between the metal if the keel is cast iron?

thanks!

1/ shotblast will get you the best finish
2/ galvanising will be the best protection but you will then have problems with adhesion of paints inc antifoul. And galv will wear where it rubs on the trailer. So maybe the best overall answer is epoxy applied at the time the keels are blasted ( ie not a day or so afterwards)
3/ I wouldnt use stainless bolts, and I say that having worked in the stainless / alloy steel industry most of my life. Best use galvanised ordinary steel.
4/ when you have blasted the keels it will be easuy to see if they are cast or fabricated from plate - the distinction between iron and steel is irrelevant for practical purposes. If they are of uniform thickness and maybe with welded end plates then they will be from rolled steel. If they are profiled then they will be cast. In both cases erosion is likely to have been localised - you wont get general erosion uniformly across the surface. So look mfor bad deterioration near the roots of the keels. Once blasted they can likely be made back up with weld anyway.

 

[Seajet]

My boat has a mild steel lifting plate, galvanised but that can scrape off.

Over 35 years I have tried all sorts of keel treatments, everything off chandlery & motor factors' shelves.

I found epoxy a bad idea as any tiniest crack will let water in then trap it against the metal.

The best treatment I have found by a very long way is Dulux Metalshield, this is 1 part but requires its' own 1 part primer.

Around here in West Sussex I get it from Brewers ( no connection ) , I doubt chandlers would have it.

 

[Alan ashore]

The best treatment I have found by a very long way is Dulux Metalshield,

Fascinating. I love hearing of non marine products that beat the specialist marine ones.

What sort of pattern of immersion does your lifting keel get? I mean in the sense that a fixed keel on a moored yacht is immersed 24/7 for a season or more at a time. And what sort of water?

Cheers,
A.

 

[boguing]

Just bear in mind that it is practically impossible to prevent an iron/steel keel from rusting permanently.

I had cause to need a keel weighed to the nearest Gram - by the National Physical Laboratory. They would only do it if it were driven straight from the foundry, and as soon as it could be got out of the sand mould. It also had to be well wrapped with insulation.

Why? I asked. Because it will take in up to 1% of it's weight in water as it cools.

So unless you can heat it to 100C for a day or two before you paint it, you are doomed to a life of scraping the patches.

 

[dartmoor]

Just bear in mind that it is practically impossible to prevent an iron/steel keel from rusting permanently.

I had cause to need a keel weighed to the nearest Gram - by the National Physical Laboratory. They would only do it if it were driven straight from the foundry, and as soon as it could be got out of the sand mould. It also had to be well wrapped with insulation.

Why? I asked. Because it will take in up to 1% of it's weight in water as it cools.

So unless you can heat it to 100C for a day or two before you paint it, you are doomed to a life of scraping the patches.

Similar to the wooden boat thread. Sadly fact of mortal life that all things, whether manufactured or organic, will degrade back to more stable elements or compounds. Iron is unstable and will always want to rust. Wood will always, eventually, break down. The best we can hope for is that these things last long enough for our enjoyment. Impressive though what can be down to slow down rust and rot...

Now if you made a keel out of Gold it would last a damn site longer!

 

[mrming]

My boat has a mild steel lifting plate, galvanised but that can scrape off.

Over 35 years I have tried all sorts of keel treatments, everything off chandlery & motor factors' shelves.

I found epoxy a bad idea as any tiniest crack will let water in then trap it against the metal.

The best treatment I have found by a very long way is Dulux Metalshield, this is 1 part but requires its' own 1 part primer.

Around here in West Sussex I get it from Brewers ( no connection ) , I doubt chandlers would have it.

Fascinating. I love hearing of non marine products that beat the specialist marine ones.

What sort of pattern of immersion does your lifting keel get? I mean in the sense that a fixed keel on a moored yacht is immersed 24/7 for a season or more at a time. And what sort of water?

Cheers,
A.

I'm interested in this too. Our iron swing keel is now out of the boat and will be blasted and primed by a professional. We are then going to re-fair it and I was going to use epoxy and something like colloidal silica to build it up before sanding. What are the panels thoughts? Is this the right approach. I'm looking to stave off the rust for a while, but more importantly I'm looking for a good shape and finish for racing.

 

[MCL]

Sorry to drag up my old thread, but I have progressed with my keel renovation and need some advice. This is what I found when I was removing my keels:

http://bit.ly/19MgluI
http://bit.ly/1coAGd1

As you can see, there was a rubber gasket in the hull/keel joint, which has completely deteriorated. My first question is should I replace this rubber gasket with a new one or just use a sealant in the joint?

In relation to the viability of the metal, the keels were designed to be approximately 34 kg each and made from 6mm mild steel plate. After removing some of the rust, I have found sections of the keel to be as thin as 4.5mm thick. I have weighed the keels and one is 28kg and the other 30kg, they still have the majority of paint on.

I have now reached a cross roads: replace my keels (out of mild steel - S275 6mm) at a cost of £175 for the pair and then get them galvanized OR renovate the old keels by getting them shot blasted £45 and then get them galvanized.

Any help on things to consider before making this decision would be appreciated.

Some more photos can be seen here:
http://bit.ly/1cp6hYu
http://bit.ly/1bCdNiA
http://bit.ly/1bCdR1S
http://bit.ly/1coBhvf

 

[Seajet]

I admit I find it hard to make things out from the pics, but to me there's no contest, if you can get a pair of new keels for £175 grab them quick before they change their minds !

If you want galvanising properly done I expect you know ' hot dip ' is the answer, not spray.

For those who asked about my using ' Metalshield ' paint by Dulux, sorry I didn't see your questions; my boat spends about 7 months a year on a half tide mud mooring.

The lower few inches of the mild steel plate get wet for about 8 hours out of 12 every tide, salt water.

There is no mud accretion to hold water against the plate when the tide has gone.

I wish I could say the boat is used every weekend and a 3 week holiday, she used to be, lately gets a half dozen weekends and if lucky a 2 week cruise when the keel is usually left down fully immersed.

I remain a great fan of Metalshield ( 1 part with special 1 part primer ), the results are still fantastic compared to anything else I've tried inc Primocon, Blakes steel treatment, 709 epoxy ( avoid that one, slightest chip traps salt water against the steel ! ) and everything else I could find in chandleries & engineering places.

 

[MCL]

I admit I find it hard to make things out from the pics, but to me there's no contest, if you can get a pair of new keels for £175 grab them quick before they change their minds !

If you want galvanising properly done I expect you know ' hot dip ' is the answer, not spray.

For those who asked about my using ' Metalshield ' paint by Dulux, sorry I didn't see your questions; my boat spends about 7 months a year on a half tide mud mooring.

The lower few inches of the mild steel plate get wet for about 8 hours out of 12 every tide, salt water.

There is no mud accretion to hold water against the plate when the tide has gone.

I wish I could say the boat is used every weekend and a 3 week holiday, she used to be, lately gets a half dozen weekends and if lucky a 2 week cruise when the keel is usually left down fully immersed.

I remain a great fan of Metalshield ( 1 part with special 1 part primer ), the results are still fantastic compared to anything else I've tried inc Primocon, Blakes steel treatment, 709 epoxy ( avoid that one, slightest chip traps salt water against the steel ! ) and everything else I could find in chandleries & engineering places.

I have asked for a few quotes but I take it thats a good one? I am also getting a couple of other bits made (chainplates, trailer parts) so maybe they lowered the cost slightly. Cost of stainless (316) steel keels would of been £525 for a pair, a bit out my price range.

I take it 275 grade is ok for mild steel?
Any thoughts on the best course of action for the keel/hull join --- gasket or just sealant?

 

[Highndry]

Seajet, so you don't put anti foul on the keel? Mine will be staying wet all next Summer (lake) and I wasn't sure whether to anti foul the keel?

 

[Seajet]

No antifoul on the keel plate.

I should mention though the design of the keel on the Anderson 22;

It's a 3/4" thick tapered & shaped mild steel plate in a fairly tight slot - too much paint and it will jam momentarily on the way down which is by controlled gravity - into a ballast bulb which is veed on top to fair in with the hull; I don't get stones or even wee beasties in the keelcase.

I put one coat of eroding antifoul on the cast iron ballast bulb a few weeks before launch but don't expect it to last long in the soft mud at the mooring; still there's no weed and just the odd very small barnacle when she's lifted out.

That's with International Cruiser, Uno or sometimes Micron self eroding antifoul in Chichester Harbour.

With different keel designs I suspect a bit of antifoul wouldn't go amiss but be careful about the paint suiting the material re galvanic action.

If going further in deep water with the keel down a lot or even constantly I'd antifoul it, and raise the keel now and again to hopefully show any hangers on who's boss !

 

[MCL]

If you are keeping it on Rutland water, don't worry about it. I used to work there and the ribs would come out with hardly any fouling on them at the end of the season. They were in treated.

 

[Seajet]

I hadn't noticed location -Rutlands' a reservoir - I'd think any antifouling is a BIG no-no ?

When I sailed a dinghy on reservoirs decades ago they were very snotty about enamel paint types, they'd have had a purple fit if anyone mentioned antifouling !