I’ve been working on reducing the rate of corrosion and abrasion on Soave’s aluminum parts. One approach has been to replace stainless shackles with dyneema where feasible.
Today I was working on Soave’s mast collar ( Photo 1 ) and discovered a crack ( second hole from the right ) . ( Photo 2 ) is a closeup of the damaged area. It was concealed by the shackle but looks like it’s been that way for a while.
For now I’ll avoid using the damaged hole, in the longer run I’ll need to either replace or somehow reinforce the mast collar.
Anyone have experience with mast collar failures ?
Rob
s/v SOAVE
NS33 #009
Cedar Point YC
Westport, CT
Hi Rob,
I don’t get most of the emails from the Google Group and I didn’t see this one until the mirror from Discourse, so I’m going to answer this here in the Discourse group. And then, to make things more confusing, I’m going to refer you back to the Google Group.
I have had a problem with a cracked fairlead collar. You can read about it here (scroll down a ways) and here. The crack was in a different place and I don’t know if it will be helpful, but there might be something useful in there. It’s not cheap to buy one from Mike Quill, but it looks like you’ll probably need a new one and hopefully he still has one left. Or he’ll have to have one cast and that will take a while, so you probably should contact him sooner rather than later.
In the mean time, maybe you should put your second reef on that or put both reefing blocks together on one of the other holes (if that won’t cause too much tangling.)
Good luck.
I’m also primarily on Discourse now and answering from there. Brian’s posted a lot on his mast collar problems and looking them up will be informative.
My recollection is that the crack in Brian’s collar was at the flange where one piece of the collar bolted to the other. If that’s correct, his was clearly a replace rather than repair situation.
My suggestion would be to send those pictures to Mike Quill and get his assessment using the INA’s consulting arrangement with him.
It may come down to needing to replace the collar. However, it may be that some lesser solution is feasible and sufficient. E.g., I wonder if it might be possible to get a sleeve installed with grommets top and bottom to prevent point loading on the crack.
Certainly your use of soft shackles is going to reduce point loading and spread the forces a bit. Mike would know.
I thought about the sleeve idea, but I think it would need to be stainless steel and I got the impression that he’s opposed to using SS along with aluminum. Even if it did result in some corrosion, I think it would be years in the making. But by then it might be impossible to get a replacement fairlead collar.
It’s worth a try, but might be best to talk to the welder before removing the collar. I considered that in my situation, but the welder said 1) he’d need to know the alloy, and being a casting he couldn’t guess at it. My break was at the flange where you bolt the two halves together, so maximum strength was important. And 2) he couldn’t guarantee the fit that I was requesting. In Rob’s case #1 is a concern, but #2 is not. Mike Quill should either know the alloy or be able to get it from his casting outfit. Or Rob might find a welder who is less meticulous and just gives it his best shot - in which case it might not be perfect, but good enough. Especially with those soft shackles.
There is another alternative that just occurred to me. I think I still have my broken fairlead collar. And my break was on the port side, while Rob’s is on the starboard side. I’m not sure where I put them, but if I can find them it might be possible for him to use the half of mine that is not broken. Rob, if you are interested let’s talk about this in messages.
Hi Joe,
Thanks for the suggestion. Welding is a possibility. I’ve stick-welded farm equipment, so I know this is way out of my league.
The challenge these days (for me) would be finding the right shop. I know from my beer brewing hobbie not every shop that says they weld stainless can actually do a good enough job to add a fitting to a kettle. I suspect aluminum requires a similar skill level.
Also, I’ve heard the surrounding cast aluminum is weakened by the heat of welding.
I’ll keep in mind, welding as a possibility and continue to assemble other options. For now, the damaged hole won’t be used.
If all else fails, here’s an interesting alternative which I saw while judging the Concours d’Elegance at last year’s INA International. This was on Baroness, the winning boat.
This was clearly custom fabricated, and I have no idea as to cost.
However, based on having assembled stainless steel fittings out of 1" tubing and off-the-shelf parts, I’m pretty sure I could replicate an uglier but otherwise equivalent version for $300 or so.
Took another look at Photo 2. Did you notice the smaller crack at about the 2 o’clock position? That means the whole section of the casting is preparing to break off.
If you’re taking the collar to a shop, try asking an open-ended question about how they’d approach the repair — just to hear their thought process. No need to steer them or mention what you already know.
On a part like this, that’s going to be under serious stress, you want someone who talks about things like: grinding the crack open properly, slowly preheating the entire casting, only starting the weld when everything’s at temperature, and letting it cool down gradually afterward.
If they skip all that and just say “we’ll weld it up real quick,” that tells you plenty.
Also — just looking at the photo — it kind of seems like the crack may have started because the casting doesn’t sit quite right around the mast. If it’s the original aluminum mast, that shouldn’t be an issue, but from the photo it looks like you might have a carbon mast? Make sure the casting fits snugly, and definitely not too loose.
The direction of the crack is a bit odd, and the rest of the collar doesn’t really look like it’s been overstressed. It makes me think the crack may have started from being over-tightened just to make it fit. That’s just a theory, but it’s something to keep in mind when you take it off or put it back on.
Update - The crack(s) in Soave’s mast collar are near spot where the turning block for her topping lift was attached. In addition to exploring the replace vs repair options for the collar, I gave some thought into the impact a failure would have had if the cracks had not been before failure. The possible outcomes if the collar failed while underway are worrisome.
( HERE ) is a closeup of the damage. Note the main crack at about 7 o’clock and there is there is a second crack beginning to develop at 2 o’clock. Credits to Mike Quill and Brian Godfrey for noticing the second crack. The second crack gives a hint about how a failure might happen. A large piece of the collar might separate and allow the block to fly free allowing the choker line to feed out enough for the boom to lower ( if the block is released the vertical forces will transfer to the deck organizer).
I tested this scenario and discovered that Soave’s wishbone would damage her bimini and likely injure anyone standing at the helm . Soave’s safety strap for the choker block and tackle was about a foot too long… or perhaps her static topping lift is too long ? ( HERE ) is a photo of the new dyneema safety line I made and installed and the old wire one doubled back to show how much longer it is. I suspect I’ll shorten the static part of Soave’s topping lift next winter after some more practice reefing and dialing in the ideal length.
Some things I wish I had done sooner :
During my fall 2024 mast inspection I should have removed all the shackles to get a clear view of the the mast collar.
I should have eased Soave’s topping lift and observed where the boom ends up if the safety was supporting the wishbone.
I should be more observant during inspections ( use penetrating dye ). I did not see the second crack till I enlarged the photo and I wonder if I missed any other cracks during inspection.
Many thanks to everyone offering suggestions. The current options are :
Replace with a new cast aluminum collar. ( preferred but expensive )
Fabricate a replacement collar with G10 ( very time consuming, probably need CNC milling to get it right )
Weld the current collar. ( requires high skill and may not be as strong afterwards )
Continue to use the remaining holes of the existing collar. ( Awkward rigging for reef lines )
Find a used collar or parts from one that are complementary to the undamaged parts of mine.
New thoughts are all welcome.
Rob
s/v SOAVE
NS33 #009
Cedar Point YC
Westport, CT
NS233
(Bob Neches, Me Gusta, Nonsuch e26U #233)
12
Rob,
In the five alternatives you laid out for the mast collar, you left out the possibility of fabricating a freestanding turning block support like the example I posted from Baroness.
I’m reluctant to push it hard because it’s just something I’ve seen and not something I’ve analyzed and/or tested. But, I am curious if you passed it over because you missed it or because you considered it and rejected it. Others might run into the same problem, and it’d be good to know whether or not Baroness’ approach is a viable alternative.
Also, regarding your comment that perhaps Soave’s static topping lift is too long, I’d like to offer a thought. If you find yourself reefing very often, it might be good to check where the static topping lift terminates with respect to your reefing clew(s) when the sail’s reefed. IMHO, it’s easier to raise the boom up with the adjustable topping lift than the aft reefing line. It’s nice to be able to raise the boom enough before tightening the aft reef line, then ease the topping lift until the sail’s taking the weight of the boom at the reef clew.
Posting on Google Groups so both audiences can follow this conversation.
An additional option offered by Bob Neches is to use a deck mounted fixture for the turning blocks. I know of two NS3’s that use this approach and it seems to work for them.
I was initially attracted to this option, but worry about finding a fabricator willing to take on the job for a price comparable to the new replacement.
The deck mounted fixture has the advantage of resolving the height issue of the blocks relative to the deck organizers. The collar on 33’s makes it difficult to access mast wedges because it blocks the mast boot from sliding up more than a couple inches. Sadly, this spring, a frustrated rigger cut my mast boot to make it easier to place the wedges.
Bob also points out that I’ll need to use the height of my reef points to gauge the optimal length of Soave’s static topping lift. I’ve already decided I’m not willing to climb the mast to replace the topping lift… it can wait till next season… but I’ll take the necessary measurements in the next few weeks to determine if adjustment is necessary.
I also kinda like the idea of keeping Soave in her original state if possible. Seems like her rig design uses lots of subtle design elements that I don’t yet fully understand.
It’s fun to navigate boat questions like this, I hope others find the discussion useful.
Rob
s/v SOAVE
NS33 #009
Cedar Point YC
Westport, CT
A deck fitting would offer a clean solution.
Stand up blocks would look better.
The relationship of the blocks to the deck organizers is a bonus.
BUT
I think it would be necessary to include a wire or two just to hold the deck down.
The collar could be fixed by:
Milling the entire aft edge away
Creating open slots where there were round openings
Forming a round bar to fit against the newly milled surface
Welding that bar to the casting
The cautions, previously suggested, concerning welding procedures would have to be observed
Selection of the material for this bar and the welding rod, would be very important.
I think the bar could be, in the order of, 1/2"-5/8" in diameter.
Hi Mark,
Good point about the length of the safety. I’ll double check the close-hauled sail shape next time I’m out.
I’ve been practicing my dyneema spicing so I’m prepared to make a new safety.
I’ll need to investigate the deck mount option further. I wonder if others can weigh in on the pros and cons ?
Lastly, I have to admit drilling more holes in Soave runs a bit contrary to my intent to preserve her, but I understand if done well any change is possible.
Thanks,
Rob
s/v SOAVE
NS33 #009
Cedar Point YC
Westport, CT
The point of the safety is to catch the boom before it hurts someone or damages something. I like your shortened one for that reason.
Mine was setup perfectly for this until I had a rigger make a new topping lift. He shortened the upper part about 6" (at my request), but didn’t lengthen the safety to match. So I added a large soft shackle to extend it and I still need to get another to make it perfect again. Perfect meaning the boom rides just above the roll bar, which is the highest point in my cockpit. And with it set there I do not see any problems with sail shape - though I am definitely not a high performance sailor. I mostly use the topping lift when reefing. On my boat/sail you cannot lift the boom with the aft reefing lines without possibly collapsing the boom tubes. I need to lift the boom then tighten that line, then lower the boom again. I have yet to figure out (and mark) the perfect heights.
I would like to address the deck mounted alternative.
You can think about the stresses involved almost like an electrical circuit. In the standard configuration (NS33 - I can’t speak to other models) all of the stresses of sailing are contained within the mast and the cabintop winches. The halyard pulls up through the sail against the tack collar which pulls up against the fairlead collar through the tack bar. The fairlead collar pulls up against the bottom of the sailtrack pad - that weird aluminum extrusion which is taped to the mast (they used double-sided carpet tape) and secured to the mast with bands. And so the stress is returned to the mast and the circuit completed. All stresses in the circuit are neatly contained in that straight line. Simple and elegant.
When you reef, things change. Now the stress goes from halyard through the sail to the reefing line. One side of that reefing line is attached to the tack collar, which now takes only half of the tension and passes it through the tack bar to the fairlead collar. The other side of the reefing line goes through a block on the fairlead collar and back to a winch, thus imparting the other half of the stress to the outside of the fairlead collar then through the web of the collar to its inner edge where all of the stress is then transferred up into the mast through the sailtrack pad. A little more complex, but still all contained within the mast.
When you make a deck mounted replacement for the fairlead collar you are going to create a much more complex “circuit” for the stresses to follow. It isn’t just going to be a question of bolting it down securely to the deck. The stresses will find their way back into the mast. And it may be difficult to control how that happens. I cannot see a good way to do that on my boat. The setup in Bob’s photo shows it bolted to the deck above the mast stabilizing bulkheads. Those are probably pretty strong, but were designed to take lateral stresses from the unstayed mast, not to pass stresses to the mast step. I think they will mostly just spread the load around the deck a little, but the pull will still be upward on the deck. It’s really not made to work that way.
Regarding Fran’s idea. It’s very interesting. An alloy of aluminum bar could be chosen which would probably be stronger than the cast aluminum. Could the two dissimilar alloys be welded with the weld being at least as strong as the casting? Would it be reliable? You’d need to talk to a really good welder because I have no idea, but it’s intriguing.
I think I’d make the diameter of the rod the same as the thickness of the fairlead collar web. Half inch seems way too small and I think 5/8 would be, too. Measure and be sure.
You’ll want to get it anodized after welding. Then you should definitely use those soft shackles because I have a hunch that bar stock will wear away faster than the casting. I’ve been amazed that my aluminum casting shows no wear from the stainless shackles than are attached to it.
I was thinking of a 1/4" thick SS plate with a few large fairlead type
of rings welded to it. Water jet to some pleasing outline.
This crescent or straight piece need not be to much larger than present hole pattern in the existing mast collar
A similar shaped backing plate
Weld to the backing plate two rings
From them run SS wire & turnbuckles to suitable bulkheads.
