Keel bolts on Sadler 32.

[Skipperwill]

Wonder if anyone has experience or knowledge of keel bolt attachment on a Sadler32?
I have recently cut away the grp encapsulation to see condition of bolts, which with stainless nuts appear to be in good condition, but find the reinforcing plate underneath has corroded, was maybe not stainless but mild steel?
Has anyone come upon this?
Yours aye,
Skipperwill

 

[SaltIre]

Mike Lucas might be able to advise:

Technical knowledge of the range of Sadler and Starlight yachts is now almost exclusively held by Lucas Yachting, who are familiar with build and specification detail for Sadlers and Starlights built from the early days in 1975, right through to Bowman-built Starlights up to 2002.
About Us | Lucas Yachting

 

[James_Calvert]

If it helps, I think ours are galvanised steel. Certainly not stainless.

Clean them off and they'll probably look fine. Never done anything with ours.

 

[Skipperwill]

Thanks for that so quickly and the information, the plates were galvanised! Apart from cost I wonder why they weren't of the same material as the bolts and nuts, after all dissimilar materials, encourage galvanic action.

In this case though, the previous owner said he cut away the encapsulation to check the nuts, then left them exposed.

That was some 25 years ago: condensation, rainwater ingress, a one off leak in the fresh water system has got to those plates!

Sadly, the two plates now exposed are too far gone for wire brushing: they will have to be replaced hopefully with stainless steel. Now I will be checking the condition of the others where there are cracks in the encapsulation and maybe the sound ones too, see what's hidden?

And lastly, all this began with the boat Rappel, once Kastor was partially lifted with a stern strap caught on the outer corner of raked keel then dunked back in sea. Salt water was found in stern bilge suggesting the keel to hull seal has been disturbed. The yard not admitting responsibility insist it's because she is an old boat!

Rapell was built 1979 one of 24 for a Greek flotilla based in Lefkada and is currently based on island of Leros in the Dodekanissos.

Thanks for the information, much appreciated.

Next question though, how to protect exposed nuts; paint with epoxy resin, encapsulate, etc?

Skipperwill.

 

[andsarkit]

If you want to regularly inspect them, you could use Denso tape.
It is rather messy to apply but will stop corrosion.

 

[Tranona]

Thanks for that so quickly and the information, the plates were galvanised! Apart from cost I wonder why they weren't of the same material as the bolts and nuts, after all dissimilar materials, encourage galvanic action.

In this case though, the previous owner said he cut away the encapsulation to check the nuts, then left them exposed.

That was some 25 years ago: condensation, rainwater ingress, a one off leak in the fresh water system has got to those plates!

Sadly, the two plates now exposed are too far gone for wire brushing: they will have to be replaced hopefully with stainless steel. Now I will be checking the condition of the others where there are cracks in the encapsulation and maybe the sound ones too, see what's hidden?

And lastly, all this began with the boat Rappel, once Kastor was partially lifted with a stern strap caught on the outer corner of raked keel then dunked back in sea. Salt water was found in stern bilge suggesting the keel to hull seal has been disturbed. The yard not admitting responsibility insist it's because she is an old boat!

Rapell was built 1979 one of 24 for a Greek flotilla based in Lefkada and is currently based on island of Leros in the Dodekanissos.

Thanks for the information, much appreciated.

Next question though, how to protect exposed nuts; paint with epoxy resin, encapsulate, etc?

Skipperwill.

There is no issue with galvanic action with mild steel and stainless - the corrosion is rust. If you replace with stainless then there is no need to paint. Many other boats of that era such as Moodys used mild steel and it is common to paint the nuts and tops of studs, either with Hammerite or a bitumen based paint. As you have discovered GRP encapsulation is not necessarily a good idea - OK if it stays sound but any crack will let water in.

 

[vyv_cox]

When Sadlers were built, relatively large heavy gauge plates were quite exotic, so most builders used galvanised mild steel. Perfectly ok when dry but many owners experienced leaking windows giving wet bilges, so some surface rust is common.

 

[Skipperwill]

Thanks for that, but it seems self evident that in damp moist conditions found on any boat dissimilar metals in contact will lead to corrosion and in salt laden air?
Now want to see what I find under fully encapsulated bolts, whether moisture found a way in along the edges under the cabin sole?

 

[Tranona]

Thanks for that, but it seems self evident that in damp moist conditions found on any boat dissimilar metals in contact will lead to corrosion and in salt laden air?
Now want to see what I find under fully encapsulated bolts, whether moisture found a way in along the edges under the cabin sole?

The corrosion is straightforward rust, not the result of galvanic action. Although the water may be saline it is more likely to be fresh (which is not an electrolyte) and it is the mild steel exposed to water that causes the rust. If the encapsulation is sound you will probably find pristine metal underneath. If it has cracked and water has got in then there may be rust - although if this is extensive chances are the rust will have expanded (as it does) and ruptured the encapsulation. Encapsulation was quite common in that period and generally it has stood up well.

 

[Skipperwill]

Apologies for a late acknowledgement, but thank you very much for your explanation: the yard here has fitted galvanised backing plates!
I did strip away the grp cladding using a Dremel and leverage to reduce dust, finding another layer of grp, the original encapsulation beneath! Everyone one of the eight plates were badly corroded: I filled a bucket with rust debris. What was left was still sound with just a trace of salt in the rear bilge where the lifting strap had caught the keel.

However, on a closer inspection today, they only finished yesterday, I see that the backing plates do not contact the hull along their entire length: they appear to have been preformed to a curve leaving a finger wide gap at each end. The bilges on a 32 are compartmentised and very shallow the plate ends out of sight except for one in a storage compartment.

Am I right in thinking such plates would or should be bedded in and in contact with hull along their entire length? Or is this a satisfactory job?

Yours aye,

D

 

[Bajansailor]

Skipper Will, do you have any photos that you can post to show what plates / bolting arrangement looks like please?

Am I right in thinking such plates would or should be bedded in and in contact with hull along their entire length?

It certainly would be a 'better' job if the plates were properly bedded in and in contact along their length.
Photos would help here.

 

[keel over]

Apologies for a late acknowledgement, but thank you very much for your explanation: the yard here has fitted galvanised backing plates!
I did strip away the grp cladding using a Dremel and leverage to reduce dust, finding another layer of grp, the original encapsulation beneath! Everyone one of the eight plates were badly corroded: I filled a bucket with rust debris. What was left was still sound with just a trace of salt in the rear bilge where the lifting strap had caught the keel.

However, on a closer inspection today, they only finished yesterday, I see that the backing plates do not contact the hull along their entire length: they appear to have been preformed to a curve leaving a finger wide gap at each end. The bilges on a 32 are compartmentised and very shallow the plate ends out of sight except for one in a storage compartment.

Am I right in thinking such plates would or should be bedded in and in contact with hull along their entire length? Or is this a satisfactory job?

Yours aye,

D

I also have a S32 with corroded backing plates, tried to PM you with some questions but not allowed, perhaps because I just joined, if you wouldn't mind swapping notes please would you PM me

 

[john_morris_uk]

Why by PM ? Any problems found and solutions you came up with would be of great interest to a great many people.

 

[James_Calvert]

Curious about a comment above about the visibility of these plates. All ours on an '85 built 32 are easily visible under the lift out sections running down the centre of the cabin sole. As built from new.

The plates themselves are also relatively small, and the hull shape quite flat in the area, as it would be over the root of the keel. So no problem with matching/filling under any hull curvature.

 

[Poey50]

Curious about a comment above about the visibility of these plates. All ours on an '85 built 32 are easily visible under the lift out sections running down the centre of the cabin sole. As built from new.

The plates themselves are also relatively small, and the hull shape quite flat in the area, as it would be over the root of the keel. So no problem with matching/filling under any hull curvature.

Same on our 1986 build. I think earlier ones had bigger and encapsulated plates.

 

[Bilgediver]

However, on a closer inspection today, they only finished yesterday, I see that the backing plates do not contact the hull along their entire length: they appear to have been preformed to a curve leaving a finger wide gap at each end. The bilges on a 32 are compartmentised and very shallow the plate ends out of sight except for one in a storage compartment.

Am I right in thinking such plates would or should be bedded in and in contact with hull along their entire length? Or is this a satisfactory job?

Yours aye,

This is not right. It suggests that the keel bolt may have been overtightened and the hull material compressed under the nuts and then the nots followed up by further tightening . If the steel plate does not sit on a flat surface and also the plate is rusty and lost material then it is unable to spread the load over its length which is what it is intended to do.

I would remove the nut and washer and check the hull below for flatness and replace the steel plate .

 

[vyv_cox]

However, on a closer inspection today, they only finished yesterday, I see that the backing plates do not contact the hull along their entire length: they appear to have been preformed to a curve leaving a finger wide gap at each end. The bilges on a 32 are compartmentised and very shallow the plate ends out of sight except for one in a storage compartment.

Am I right in thinking such plates would or should be bedded in and in contact with hull along their entire length? Or is this a satisfactory job?

Yours aye,

D

These are two of the keel bolts on my Sadler 34, not a great deal different from the 32 I think. The galvanised steel plates are flow-coated (gelcoat plus wax) and are flat. They sit squarely on the hull. These are original and have never been disturbed. I cannot imagine why yours are curved.

 

[Poey50]

These are two of the keel bolts on my Sadler 34, not a great deal different from the 32 I think. The galvanised steel plates are flow-coated (gelcoat plus wax) and are flat. They sit squarely on the hull. These are original and have never been disturbed. I cannot imagine why yours are curved.View attachment 147505

Those look identical to those on our 1986 Sadler 32.

 

[keel over]

Photos of Sadler 32 keel bolt backing plates and a previous attempt to deal with the problem posted here:
S32 Keel bolts
On this particular 1979 32 the keel is bolted directly through the hull and into the keel - no keel stub or other load distribution.
The bolts are M24 course thread i.e. a lot of torque to be distributed if they are tightened up to levels recommended for bolts of this size.
After 4 years rust is showing through the coatings which are lifting off so its time to do it again.

 

[keel over]

Photos of Sadler 32 keel bolt backing plates and a previous attempt to deal with the problem posted here:
S32 Keel bolts
On this particular 1979 32 the keel is bolted directly through the hull and into the keel - no keel stub or other load distribution.
The bolts are M24 course thread i.e. a lot of torque to be distributed if they are tightened up to levels recommended for bolts of this size.
After 4 years rust is showing through the coatings which are lifting off so its time to do it again.

It would be relatively easy to replace these with the smaller, one backing plate per bolt, arrangement shown in the S34 and mentioned by others as being present in later 32s, however one would want to be sure that there weren't some other changes in e.g. load distribution, that would stop this from being an option - if anyone has pictures of these areas in a later 32 then I'd be interested to see them - anyone can upload to the gallery in my previous post.