Stem head forestay attachment issue

[Overandunder]

I have recently bought an awb in the form of a Jenny SO 29.2 (2006). As the history of the rigs maintenance is somewhat murky I'm in the process of replacing it.

All straightforward enough - until I came across the forestay attachment point on the alloy stem fitting. I can't use the rearward point as the fitting for the furler wouldn't clear the deck at that point.

So the question is - can I (carefully and accurately) simply drill a new 10mm hole in between both points ? I realise the better solution would be wholesale replacement in stainless - but I'm after a simple and easy fix, albeit 'temporary'

Thanks all

 

[Porthandbuoy]

I think it might be safer to fit a toggle between the rearward fitting and your furler. Unless the elongated, worn hole is the forward fitting. That's not clear from your photo.

 

[srm]

Possibly.
Assuming the hole that is elongated was carrying the load of the forestay ensure that the new hole has at least the same cross section area (before elongation) of metal both above and to the sides to take the loads.

 

[Overandunder]

I think it might be safer to fit a toggle between the rearward fitting and your furler. Unless the elongated, worn hole is the forward fitting. That's not clear from your photo.

The elongated hole is the foremost one and has been in use from new as I understand it - no other SO 29.2 owners seem to use the 2nd one.

 

[wrr]

Can you carefully enlarge the worn hole, working downwards to avoid losing metal above, finish it as a true circle and press in a sleeve? That might hold until you have a stainless stem fitting fabricated.

 

[Overandunder]

Possibly.
Assuming the hole that is elongated was carrying the load of the forestay ensure that the new hole has at least the same cross section area (before elongation) of metal both above and to the sides to take the loads.

Exactly that - sorry this wasn't made clear - the elongated hole has been in use since day 1. From what I understand no owner seems to use the 2nd one (on the left of the photo). I've edited the original post now.

 

[MontyMariner]

I don't know the style of the fitting and it's not clear from the picture, is it a single fin or a two fin fitting with the forestay sandwiched between?
If single fin, I would drill out as described above, wire brush all the oxidation off and make an L shaped re-enforcement plate that bolts through both holes. If done in stainless, give it a good coat of Duralac.
A double fin shouldn't need re-enforcement.

 

[srm]

Some more ideas:

If this is indeed a temporary fix rather than a metal sleeve perhaps filling with "metal repair epoxy" then drilling a new hole at bottom. Or wax the clevis pin so it can be removed and carefully fill with the epoxy above it. Most metal repair epoxys claim they can be drilled and tapped so may well last a season or two in compression. It has taken 18 years for the fitting to get to its present state so its a case of spreading the load evenly on the remaining metal.
It should be checked visually from time to time.

Taking @MontyMariner post a step further. Bolt two ss plates to sandwich the present fitting with a mid way holes to take a long clevis pin and an eye end to forestay rather than the fork that has been used. However putting ss against the alloy will need some form of electrical separation (paste or plastic) to prevent electrolysis of the alloy fitting.

 

[Fr J Hackett]

The elongated hole is the foremost one and has been in use from new as I understand it - no other SO 29.2 owners seem to use the 2nd one.

I just daren't comment on that

But to answer the original question I would use two plates to sandwich the original fitting as has been suggested.

 

[rogerthebodger]

I would do as wrr says and open up the hole and fit a stainless-steel boss that would add strength to the hole as the boss would have a larger bearing area in the softer aluminum

 

[srm]

I would do as wrr says and open up the hole and fit a stainless-steel boss that would add strength to the hole as the boss would have a larger bearing area in the softer aluminum

Good in theory. Depending on the grade of alloy that risks electrolytic corrosion of the alloy. I have seen ss bolts tapped in alloy castings reduce the alloy in contact to powder in a month in sea water. After six months there was no usable thread left. Perhaps a hard reinforced plastic boss would be better.

 

[rogerthebodger]

Good in theory. Depending on the grade of alloy that risks electrolytic corrosion of the alloy. I have seen ss bolts tapped in alloy castings reduce the alloy in contact to powder in a month in sea water. After six months there was no usable thread left. Perhaps a hard reinforced plastic boss would be better.

Yes I see what you mean

I do have stainless steel screws in an aluminum windlass casting may be if the bush is fitted with some sealant would isolate the stainless from the aluminum

 

[srm]

Yes I see what you mean

I do have stainless steel screws in an aluminum windlass casting may be if the bush is fitted with some sealant would isolate the stainless from the aluminum

Yes, stainless steel items are fitted to alloy masts, however they use a plastic backing on larger items and an insulation paste for rivets and bolts. I seem to remember zinc oxide paste but could well be wrong. The stem fitting is presumably a good marine alloy, but its as well to take care when mixing metals.

 

[Overandunder]

Trying to post a more self explanatory pic - but it's being rejected as too large !

 

[Overandunder]

I have recently bought an awb in the form of a Jenny SO 29.2 (2006). As the history of the rigs maintenance is somewhat murky I'm in the process of replacing it.

All straightforward enough - until I came across the forestay attachment point on the alloy stem fitting. I can't use the rearward point as the fitting for the furler wouldn't clear the deck at that point.

So the question is - can I (carefully and accurately) simply drill a new 10mm hole in between both points ? I realise the better solution would be wholesale replacement in stainless - but I'm after a simple and easy fix, albeit 'temporary'

Thanks allView attachment 183057

 

[Overandunder]

I don't know the style of the fitting and it's not clear from the picture, is it a single fin or a two fin fitting with the forestay sandwiched between?
If single fin, I would drill out as described above, wire brush all the oxidation off and make an L shaped re-enforcement plate that bolts through both holes. If done in stainless, give it a good coat of Duralac.
A double fin shouldn't need re-enforcement.

Single fin style casting (inverted 'T' shape if you will).

 

[Overandunder]

 

[Overandunder]

Thanks to all for the suggestions. I can't widen the existing upright section as the forestay fitting loops to either side of this and can't be expanded (there is a proper name for it but I cant recall what it is- basically it's a flat piece of stainless looped around in a 'U' shape and held by a clevis pin through the deck fitting).

 

[Fr J Hackett]

What's temporary? if it's a year or so you could safely use it as it is and monitor it, with the correct forestay tension there should be little to no movement.

If you can find someone that can weld Aluminium then a piece inserted in the hole and welded in then drilled would be a permanent solution.

 

[Overandunder]

What's temporary? if it's a year or so you could safely use it as it is and monitor it, with the correct forestay tension there should be little to no movement.

If you can find someone that can weld Aluminium then a piece inserted in the hole and welded in then drilled would be a permanent solution.

That's the way I'm hoping to go - drill a new hole. Just curious if anyone else has done this really.