Sidestay back plate pulling through hull

[GreenLake]

Instead of thread locker you would use TefGel, a rather expensive (per ounce) compound sold, I think in a 1/2 oz. package, but one that's formulated for the task of keeping aluminum and stainless steel separated for corrosion control. A very small amount of it goes a long way.

You may not have easy access to a rigging shop where you are located, so perhaps checking the rivets for signs of corrosion and leaving well enough alone is the best course.

There may be others here who have a better handle on the issue of rivets, all I know is that I would not trust the usual hardware store rivets to be strong enough.

[K.C. Walker]

For attaching the tangs to the mast, rivets are way stronger. There’s not enough wall thickness in the mast to hold threads. Pop rivets are easy to drill out because the center hole guides the drillbit. Of course, the aluminum ones are far easier to drill out than the stainless ones. One does need a pretty heavy duty riveter for the 3/16 stainless rivets, though. A lot of the aluminum rivets on my boat are still holding after 35+ years. I did have a boom bail for the main sheet break off last summer with no sign of problems before hand. The aluminum rivets were all sheared. Dwyer Mast uses stainless steel rivets and when I inquired about anticorrosion they said, “sure, you can do that but we don’t”. I use LanoCote.

[GreenLake]

Thanks for that riveting post, K.C.

Most of the rivets on my mast seem to have been unaffected by nearly 50 years of use, but some have given out. Not for tangs though. Next time that happens, I'll definitely think about SS rivets.

With saltwater in the mix, I usually take no chances when it comes to corrosion, and the effort required is minimal.

[Breakin Wind]

When considering replacing the tangs, is it concern about the possible failure of the tang itself, or rather the rivets attaching them to the mast shearing off. It sounds like the latter, that the tangs don't need to be "replaced" but rather removed and reattached with new rivets.

Is that correct?
Thanks - Scott

[GreenLake]

In general yes - as long as there are no cracks (however tiny) in the SS part. Now a tang is a rather simple object, unlike a turnbuckle, so checking for cracks should be a sight easier. Maintaining the corrosion resistance of SS requires oxygen, and cracks can be oxygen deprived environments which leads to "crevice corrosion".

Crevice corrosion is accelerated by saltwater (chlorine ions) and favorite locations are places where water can collect (such as fitting on the lower end of shrouds).

[Breakin Wind]

For attaching the tangs to the mast, rivets are way stronger. There’s not enough wall thickness in the mast to hold threads. Pop rivets are easy to drill out because the center hole guides the drill bit. Of course, the aluminum ones are far easier to drill out than the stainless ones. One does need a pretty heavy duty riveter for the 3/16 stainless rivets, though. A lot of the aluminum rivets on my boat are still holding after 35+ years. I did have a boom bail for the main sheet break off last summer with no sign of problems before hand. The aluminum rivets were all sheared. Dwyer Mast uses stainless steel rivets and when I inquired about anticorrosion they said, “sure, you can do that but we don’t”. I use LanoCote.

So... just to get the question out of the way, would it be an incredibly bad or foolish (could be both I guess) idea to use three long stainless steel screws and locking nuts passed through the mast to attach both sidestay tangs (on the same screws)?

Thanks - Scott

[K.C. Walker]

So... just to get the question out of the way, would it be an incredibly bad or foolish (could be both I guess) idea to use three long stainless steel screws and locking nuts passed through the mast to attach both sidestay tangs (on the same screws)?

Thanks - Scott

I don’t see why that wouldn’t work.

[GreenLake]

This is only simple if the tangs are located opposite of each other across the widest part of the profile. I can't check things on my mast right now, but on the DS the spreaders are swept back, which means that the shrouds don't actually pull in the same plane. It would make sense for the tangs to be mounted a bit behind the widest point of the mast profile to put them in line with the actual pull from the shrouds. If that was done, you would not have a perpendicular direction for your bolt, but it would be angled. That could be an issue.

[ChrisB]

Scott,

For what its worth, I replaced the SST rivets on my mast tangs last year (after reading a post about a dismasting due to failed rivets). I purchased new SST rivets from West Marine and they are quite a bit more difficult to "pop" than the aluminum rivets I use around the house. However I was able to do the job with my Stanley rivet tool and I have stressed them in a couple of good blows and so far, so good. Unless there is some deformation or cracking on the tangs, I wouldn't replace those.

- Chris

[Breakin Wind]

This is only simple if the tangs are located opposite of each other across the widest part of the profile. I can't check things on my mast right now, but on the DS the spreaders are swept back, which means that the shrouds don't actually pull in the same plane. It would make sense for the tangs to be mounted a bit behind the widest point of the mast profile to put them in line with the actual pull from the shrouds. If that was done, you would not have a perpendicular direction for your bolt, but it would be angled. That could be an issue.

I was able to got over to my boat this afternoon and the sidestay tangs appear to be attached exactly opposite each other across the center of the mast, so the screws through the mast could work in that case. Obviously that same process could not be used for the headstay as the mast slot is opposite it on the mast, but my from my inspection I think the tangs are in good shape and I can find no weakness or give in any of the rivets.

Thanks - Scott

[GreenLake]

I'd still follow Chris and KC and go with rivets. Somebody posted somewhere on this forum a link to a heavy duty riveting tool (still hand-operated). That would be the preferred one to use with SS rivets. However, on another boat an expert sailor neighbor did a repair of a mast ring with SS rivets using what looked like an ordinary riveting tool and it has held for years.

On that boat, the mast ring acts like a goose neck, and the plastic fitting that the manuf. had supplied had died from an overload. He fitted a SS mast ring, and I've been out in it in much higher winds than ever before, so these rivets are definitely being stressed some.

(As a total aside, and just because I mentioned this episode, he did this for free and refused payment even for the new fitting, which he himself had located and purchased at a boating store in a nearby town. I was new to sailing then, and far from competent in what now, to me, would be an ordinary repair. This has definitely inspired me to find ways I can "return" this favor by helping out others where opportunity presents itself.)

[Breakin Wind]

(As a total aside, and just because I mentioned this episode, he did this for free and refused payment even for the new fitting, which he himself had located and purchased at a boating store in a nearby town. I was new to sailing then, and far from competent in what now, to me, would be an ordinary repair. This has definitely inspired me to find ways I can "return" this favor by helping out others where opportunity presents itself.)

Pay it forward - A great movie and an fantastic approach to life. Clearly an operating philosophy on this board.

Thanks - Scott

[Breakin Wind]

For attaching the tangs to the mast, rivets are way stronger. There’s not enough wall thickness in the mast to hold threads. Pop rivets are easy to drill out because the center hole guides the drillbit. Of course, the aluminum ones are far easier to drill out than the stainless ones. One does need a pretty heavy duty riveter for the 3/16 stainless rivets, though. A lot of the aluminum rivets on my boat are still holding after 35+ years. I did have a boom bail for the main sheet break off last summer with no sign of problems before hand. The aluminum rivets were all sheared. Dwyer Mast uses stainless steel rivets and when I inquired about anticorrosion they said, “sure, you can do that but we don’t”. I use LanoCote.

Thanks KC - I tried to determine what I was looking at yesterday when I went to the boat, but simply not enough experience to recognize a SS rivet from an Aluminum one. Are the original rivets Stainless or Aluminum on the Daysailer?
Or can you (or someone else) suggest how to recognize them? I know I'd find out when drilling. If it easily drills out, its probably Aluminum. If it takes 3 drill bits and 2 batteries on one rivet, it's probably stainless.

[GreenLake]

Once they've had a few years to weather, aluminum rivets are dull, while SS ones remain shiny.

(note, if you use rivets that are hollow, you might want to seal them so your mast doesn't fill with water on a capsize).

[K.C. Walker]

+1 for what Greenlake said. Also, another easy way to tell if they are aluminum, monel, or stainless is take a tool and try scratching them.