Contessa 26 forestay rig rusting?

[dave.zap]

Hi,

Recent new owner of a Contessa 26 in Melbourne.

I was crawling around the forward berths and found a rather disturbing problem. The plate that attaches the forestay in the boat is looking a we bit rusted. Of course I'm worried it will fail.

My question is how should I go about correcting this.. it seems like a integral part of the structure?

This area also doubles as the anchor chain pit.

First image shows the rigging. And you can see where the water has dripped down off those four bolts. Probably the source of the rust.

And the plate.

Any ideas?

Dave

 

[30boat]

It looks like ordinary steel but to make sure check that's not magnetic.If it turns out to be steel and providing there's enough meat left the best option would be to grind most of the rust off (difficult in such a small space) and paint heavily with epoxy primer.After it's done cover it in waterproof grease for added protection.Removing it entirely would entail cutting that bit of the stem off and rebuilding with epoxy and rovings,easier than it seems.That's what I would do if the plate proved to be too far gone.Unless there are fixings on the outside that can be removed so that the plate can be pushed in.That would make everything much more straightforward.

 

[prv]

If faced with that on a steel sailing ship, I'd expect to get most of the rust off with a chipping hammer and possibly a wire brush on an angle grinder, then wash with metalbright (not sure what this actually is; some kind of acid that comes in blue drums and turns rust black and solid) and repaint with several coats of Jotamastic followed by topcoat. Obviously this will be more difficult upside down in your anchor locker.

I'm sure one of the engineering types round here will have a useful opinion, but to my layman's eye it doesn't look terminal. Remember that rust is seven times bigger than the steel it formed from, so a thick coating of rust can come from only a very small reduction in the thickness of steel.

Pete

 

[Chrissie]

I second what PRV says and add that if you can remove the turnbuckle and examine the edge of the hole to make sure there is enough 'meat' holding the fitting. It looks like there might be alternative holes to choose from. a car shop will sell you the rust inhibitor that goes black, but its important to coat on top of that, as you would with car body parts.

 

[Bilgediver]

First image shows the rigging. And you can see where the water has dripped down off those four bolts. Probably the source of the rust.


Any ideas?

Dave

I would suggest that you use the jib halyard to secure the mast while you disconnect the fore stay so you can carry out a full inspection of the anchorage.

I suspect the problem is the fore stay seal in the deck seal assembly which is held in place by the 4 rusty bolts. Water is running down the fore stay and maybe also leaking in around the seal plate to deck joint.

The anchorage can be cleaned up with various wire brushes used in a power drill and then well primed and painted. However I would suggest you look very carefully at the root of the anchorage where it enters the hull layup. Any wastage here could be a problem however I suspect it is unlikely to be severe in your case.

Do not be tempted to utilize other holes as you may exacerbate the leakage by pulling the stay off centre in the seal.

These boats were designed by Jeremy Rogers who is very approachable and
will be able to give you better hints and tips than us.

http://www.jeremyrogers.co.uk/


We have three of these boats layed up near mine so I may see if I can look at them to see if I get more ideas.

 

[Scotty_Tradewind]

maybe this problem has been met before
Try contacting other owners?
http://www.contessa26.net/

 

[Ubergeekian]

Any ideas?

I would want to check the condition of the steel under the fibreglass very carefully - you really don't want rust to get in there. If there is any doubt I would bite the bullet, grind the whole lot out and replace the mild steel with something in stainless. In view of the reputation of Contessas I am frankly astonished that mild steel would be used for this in the first place.

 

[Leighb]

A contributing factor, assuming that it is mild steel, must be electrolysis. A S/S turnbuckle attached to a steel plate in a wet salty area will ensure fairly rapid corrosion. Even if the plate was originally galvanised the zinc would have disappeared quite quickly in that situation.

Those more expert may wish to correct me?

 

[doug748]

Hello Dave, here is a respose from Jeremy Rogers on the theme:

...... the stemhead chainplate was originally a hot-dipped galavanised steel fitting, which was common at the time (in the 1960s). The problem now is that, with the forestay running through the deck, water will follow the stay down to the galvanised fitting. A lot of boat owners have now cut the forestay fitting and either put an eye bolt or a s/s t-shaped fitting on the deck, then under the deck they have tied the deck fitting down to the galvanised one with a rigging screw and a short piece of wire. In effect this is roughly what Jeremy did with 'Rosina'.

With 'Rosina' the grp was peeled off the fitting with a hammer and chisel and then a similar S/S fitting was bonded in to replace the galvanised one
So assuming it's in good condition, just keep the old fitting free of water by painting it each season or treating it in some other way.

You will find more discussion here:

http://www.contessa26.net/component/option,com_joomlaboard/Itemid,38/func,view/id,70/catid,3/

From the Contessa 26 Association site - well worth looking at

 

[dave.zap]

Thanks for all the ideas people,

We have three of these boats layed up near mine so I may see if I can look at them to see if I get more ideas.

If you would do that for me then you are a wonderful human being.

Today I got some wire brushes, 3M rust dissolve and 3M converter and primer.

I did look at removing the forestay, but chickened out when I realised that I would need to first loosen off the two backstays. I had the jib halyard trying to take the tension but it was not doing much.

In the end I scratched around and did the 3M combo to to it.

During my scratching I dislodged large chunks with a chisel with little effort . I foresee in my future replacing this plate with a new stainless steel one.

Hello Dave, here is a respose from Jeremy Rogers on the theme:

Thanks Doug, I'm probably heading in this direction.


Dave

 

[Ubergeekian]

I foresee in my future replacing this plate with a new stainless steel one.

I would respectfully suggest that you make that the immediate future. Just imagine being out on a blowy night wondering how far the corrosion has progressed under the fibreglass, imagining the crack widening, looking at the back stay for any reduction of tension ...

It looks like a day's work and a small amount to your local stainless fabricator. Just do it.

 

[dave.zap]

Yeah thanks., without and engine for at least another week I'll have time on my hands to deal with this problem before I go any place.

I do not intend to fall foul of murphy's law despite it having sailed fine up til this point.

 

[Seajet]

I'm 100% with Ubergeekian on this one; my boat has a near identical problem, as mentioned hard to imagine why people should use mild steel, it seems they thought the forestay tang was 'encapsulated' in GRP, not realising that the slightest bit of stress would flex the rig and allow water ingress down along the forestay.

Bearing in mind the crucial, load bearing nature of the forestay I'd indeed 'bite the bullet' and bolt in a serious bit of stainless steel, marine grade 316, pronto !

As mentioned, a dark night with the wind blowing old boots is not the time to start wondering if the rig will stay up...

I have found a rechargable 'Dremel' tool with a cutting wheel ( extra to normal bits ) invaluable for this sort of work, you'll need eye, breathing mask and arm protection too when using it.

 

[dave.zap]

I'm 100% with Ubergeekian on this one; my boat has a near identical problem.

Could you please elaborate, have you fixed this issue with your boat already?

 

[Ubergeekian]

Yeah thanks., without and engine for at least another week I'll have time on my hands to deal with this problem before I go any place.

I do not intend to fall foul of murphy's law despite it having sailed fine up til this point.

It's not Murphy's Law you have to worry about, it's a corollary of the First Law of Cartoon Physics. That's the one which says that if you run over the edge of a cliff you won't fall until you look down. Similarly, your mast would have stayed up for ever if you hadn't known of this problem.

Could you please elaborate, have you fixed this issue with your boat already?

Seajet has an Anderson 22, I have a Hunter 490. Both were by Oliver Lee, who was fond of this form of forestay attachment and so we both have setups like yours, though the Hunter one is stainless. I think ...

I'm going to check asap and if it's not I'll put replacement on the winter list, particularly since I'm planning to fit a beefed up stemhead fitting anyway..

 

[mikemonty]

I would want to check the condition of the steel under the fibreglass very carefully - you really don't want rust to get in there. If there is any doubt I would bite the bullet, grind the whole lot out and replace the mild steel with something in stainless. In view of the reputation of Contessas I am frankly astonished that mild steel would be used for this in the first place.

I'm astonished that you are astonished.

Extracted from the following source http://www.allstainlessltd.co.uk/info/useful_stainless_2.html

Stainless steels get their corrosion resistance by the formation of a very thin surface film, called the passive film, which forms on the surface in the presence of oxygen. Therefore, stainless steels usually have poor corrosion resistance in low-oxygen environments, such as under deposits, in mud, or in tight places, called crevices, where structures or hardware are attached. This is particularly true in seawater, where the chlorides from the salt will attack and destroy the passive film faster than it can reform in low oxygen areas. All of the stainless steels except the best of the specialty alloys will suffer from pitting or crevice corrosion when immersed in seawater. One of the best 300-series stainless steels is type 316. Even this alloy will, if unprotected, start corroding under soft washers, in o-ring grooves, or any other tight crevice area in as little as one day, and it is not unusual to have penetration of a tenth of an inch in a crevice area after only 30 days in seawater. If water flows fast past a stainless steel, more oxygen is delivered to the stainless steel and it corrodes less. For this reason, stainless steels have been successfully used for impeller blades and propellers. These need to be protected from corrosion when there is no flow.

 

[dave.zap]

I'm astonished that you are astonished.

I'm astonished that your astonished that he is astonished.

The existing plate, although badly corroded, has held fast since installation in 1973, so surly a stainless steel version would be an improvement?

I believe the root cause is the ingress of water that can be largely solved with new correctly sealed deck bolts.

Dave

 

[oldharry]

Thanks for all the ideas people,





In the end I scratched around and did the 3M combo to to it.

During my scratching I dislodged large chunks with a chisel with little effort . I foresee in my future replacing this plate with a new stainless steel one.


Dave

Dont worry too much if apparently large chunks came off - that is rust scale and it swells up to several times the thickness of the original. What is important is to get under it to bright metal underneath, to find out how much is left. But if that was 3/8" steel plate, and the scale was 1/8 thick, it would only have penetrated the surface by less than 1/16.

More importantly, what is the state of the hole into which the fitting goes. If it is badly ovalled, then it is nearing the end of its life. But on a fitting that thick, a bit of scale will not make a lot of odds providing you clean back and protect it properly as others have described.

 

[mikemonty]

I'm astonished that your astonished that he is astonished.

The existing plate, although badly corroded, has held fast since installation in 1973, so surly a stainless steel version would be an improvement?

I believe the root cause is the ingress of water that can be largely solved with new correctly sealed deck bolts.

Dave

I'm astonished that you're astonished that I'm astonished that he's astonished.

As the original has been in service for so long what would be the point in replacing it with a material which has a BAD history in stagnant seawater, worse than standard steels (google it).
Particularly in WARM seawater.

The previous owner of my Contessa 26 did what has been suggested on this thread - he put a plate and eys(s) in the deck for the forestay and inside he tied it down to the original tang with a bottlescrew - no flexible seal - no leaks - works fine.

 

[Seajet]

Dave.Zap,

The problem with the Anderson 22 - and may well be the same with the early Hunters as Ubegeekian mentions - is this, which seems suspiciously like your Contessa's snag;

The Anderson has a stainless forestay tang, aligned fore & aft, which disappears into a mass of grp in the anchor locker below.

A visual inspection is worthless, but after a very awkward, elbow bruising attack with a Dremel grinder it becomes clear that there's a vertical wooden pad right behind the stem.

The stainless plate runs alongside this, and is attached by an originally 12mm MILD STEEL bolt !

Water runs down the tang and corrodes the bolt; my boat is in very good condition and I was tempted to leave it; when I persisted I found less than 1 of the original 12mm left !

This is fairly easy to fix, adding backing plates to transfer some of the forestay load to the ( well secured ) foredeck underside as afurther precaution, but it's VERY awkward to get at.

If interested see the 'Buyer's Guide' at www.anderson22class.co.uk

If really unlucky the wooden pad may rot too, I saw one boat where this had happened, 'exploding' the GRP cladding.

This obviously means a lot more of a repair, cutting out the wood and rebuiding the structure.

Still within the range of a good DIY-er, or apparently around £400 for a boatyard to do it.

As this carries so much of the rig's load, I'd suggest not something to skimp on !

Please check if this is what the Contessa has, it does look similar...