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ahun · 10-04-2016, 04:36

Hi all, looking for advice in reinforcing/refurbishing the bronze stem head on my Hurley 22 (built in 1971). It has 3 holes as attachment point for the forestay (originaly without furling system). The middle one was used for decades, probably, and the PO moved it to the other one about three years ago. You can see on the photo the middle one is quite worn, but sure after more than 30 years in service it is acceptable. However, as I have a furling jib now, and it is heavier than a single forestay, and in general just to be sure, I thought I should reinforce the vertical plate with an additional bronze plate welded on one side, and then the same holes drilled through.
The question is, is welding bronze going to be strong enough/stronger than the original, or instead, it is going to compromise the strenght of the stemhead?
I am not thinking of replacing the steamhead, if not necessary for various reason.

Thanks.

Lodesman · 10-04-2016, 05:10

Unless you're keen on keeping the original bronze fitting, it might be worth considering replacement with a new stainless unit - perhaps incorporating a bow-roller or two. If you would prefer to keep the bronze jobby, then perhaps the easiest solution would be to have a piece machined to be sistered over the tang, thru-bolted in the existing 3 holes, and another much beefier hole above for attaching the forestay.

**newhaul** · 10-04-2016, 06:02

The afore mentioned way to sister is your best option. If you are dead set on keeping bronze. . You braze bronze and adding that much extra heat can deform the unit and or make it brittle. IMO your best option would be to replace the unit with stainless.

Stumble · 10-04-2016, 10:25

Ahun,

Both of the forward holes look like they can no longer be used to me. One because of a loss of metal, and the second from being wallowed out.

The one you are using I can't seen, but the attachment method is very nonstandard, and frankly would worry me. Shackles like that are not well matched to the fitting you are using and is very likely to cause substantial wear and eventually failure.

Frankly I think you need to replace the stem, and redo the rigging to properly match.

deblen · 10-04-2016, 10:37

How to join/weld bronze?

Cheechako · 10-04-2016, 10:43

I've not heard that you can weld bronze. You could braze the hole and redrill, How about just redrilling deeper into that web than those holes, then getting an extra long U shackle?

hellosailor · 10-04-2016, 10:54

Welding, on any metal, literally makes new metal seamlessly with the old, so in theory you can do perfect restoration. In practice, bronze isn't commonly worked these days, and "bronze" can be a hundred alloys so the important matching of the new metal to the old composition may not be easy.

I think I'd want to find a foundry or a specialty shop that is familiar with bronze, take the stemhead in to them, and let them see if they are confident about matching the metal versus other repair options, like adding a "shoe" over the worn area, and perhaps sleeving the holes, or something else.

There's no doubt a good machinist can make the stemhead 100% functional again, but depending on aesthetic choices, costs, and what kind of skills you can locally find...hard to really suggest anything besides "find a local shop that knows bronze" and see what they can offer you.

In the worst case (or perhaps best) a local foundry could pretty easily sand-cast a totally new twin to your old one, perhaps a little thicker or a little taller, so there's a little more meat to the holes [sic] to make them more robust, or adding in sleeves, or using a stronger alloy.

Of course if you are really brave and have a big cauldron, that's a DIY job too.(G)

ahun · 10-04-2016, 12:51

Thanks for everyone; Lodesman's idea is pretty good didn't think of that one, might consider something similar. I included the year the boat was build so maybe that would shed some light on what alloy it is exactly, as I am a bit confused with the possibilities, and if it makes any difference or not. Bronze seems to be pretty strong stuff, there is a reason it was used and lasted so far, but something needs to be done now and I am not sure, if I take it to a welder he would appreciate the importance of the outcome of the job...

Btw, there is bow roller, you can see it better here:

hellosailor · 10-04-2016, 13:43

If you ever need a headache, contact any six marine suppliers that make thru-hulls or other bronze castings. Ask each what their alloy is. Or, look on the web for what the range of alloys can be. Some are even "brass" not "bronze" if you go by strict definitions. Some are "trade secrets". (Yawn.)

If you can determine the foundry that the boatbuilder used, there's a terribly slim chance that someone will know what alloy they usually used, although many non-critical casting operations have been known to buy "close enough" scrap and just throw it in the pot, ensuring that no one knows exactly what it is.

"Close" might be good enough.

Or you could have a new one fabbed up from titanium and get that useless dead weight off the bow.(VBG)

**Jim Cate** · 10-04-2016, 14:39

Well, lets not forget tht this is a 22 foot boat... the loads are not all that great. I think the logical solution is to drill a new hole somewhere between the forward pair and much lower in the web. Make the diameter of the hole large enough that one can fit a hefty new deep D-shackle into it and use the shackle as the attachment point for the furler clevis.

I personally would not feel threatened by such a solution's strength.

Jim

Cheechako · 10-04-2016, 15:25

Quote:

Originally Posted by Jim Cate

Well, lets not forget tht this is a 22 foot boat... the loads are not all that great. I think the logical solution is to drill a new hole somewhere between the forward pair and much lower in the web. Make the diameter of the hole large enough that one can fit a hefty new deep D-shackle into it and use the shackle as the attachment point for the furler clevis.

I personally would not feel threatened by such a solution's strength.

Jim

unclemack · 10-04-2016, 18:12

Might be an optical effect but your anchor warp looks like it'll chafe on the bolt that's holding your furler to the stem fitting.
I'd want to replace that roller sheave and bolt right away, (ebay) - I wouldn't use another machine screw with threads right to the head like the present one - threads wear sheave bushes away. I'd use the next size up too, say 8mm not 6mm.
A bigger diameter sheave would help keep the warp from chafing on the bronze cheek plates when the boat sheers about in a blow.

Can't see properly but it looks like your furler may be meant for a different length stay?
If so I'd look for a total solution that addresses all the issues if possible.

This type of arrangement allows simple adjustment if you don't have any:

Those three existing holes let you adjust mast rake but if you can manage with one or two the holes can be much lower and not weaken the web.

Looking at other boats can help a lot.
Or posting more photos here

TeddyDiver · 10-04-2016, 20:30

^^ +2 As Jim says..

Zai · 10-04-2016, 21:20

Quote:

Originally Posted by Jim Cate

Well, lets not forget tht this is a 22 foot boat... the loads are not all that great. I think the logical solution is to drill a new hole somewhere between the forward pair and much lower in the web. Make the diameter of the hole large enough that one can fit a hefty new deep D-shackle into it and use the shackle as the attachment point for the furler clevis.

I personally would not feel threatened by such a solution's strength.

Jim

+1 The only thing I would add is to drill an oversized hole and have a delrin bushing machined up. It will solve the wearing out problem.