Damaged Mast Collar

[Rob Cohen "Soave" NS33 Westport, CT]

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

[Joe Valinoti]

Rob:  Have you considered removing the collar and having it welded??

 

Joe Valinoti
S/V iL Gatto NS30U #221
Sea Harbour YC
Oriental, NC USA

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[Rob Cohen]

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.

--

Rob
s/v SOAVE
NS33 #009
Cedar Point YC
Westport, CT

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[Sprio]

Rob,

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.

mark h
n36#25 Cotton Eye Joe
netherlands

Op zaterdag 21 juni 2025 om 20:31:43 UTC+2 schreef Rob Cohen:

[Rob Cohen "Soave" NS33 Westport, CT]

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 :

1. During my fall 2024 mast inspection I should have removed all the shackles to get a clear view of the the mast collar.
2. I should have eased Soave's topping lift and observed where the boom ends up if the safety was supporting the wishbone.  
3. 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 :

1. Replace with a new cast aluminum collar. ( preferred but expensive )
2. Fabricate a replacement collar with G10 ( very time consuming, probably need CNC milling to get it right )
3. Weld the current collar. ( requires high skill and may not be as strong afterwards ) 
4. Continue to use the remaining holes of the existing collar.  ( Awkward rigging for reef lines ) 
5. 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

[Rob Cohen "Soave" NS33 Westport, CT]

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

[Francis Cichowski]

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:

     1) Milling the entire aft edge away 

     2) Creating open slots where there were round openings

     3) Forming a round bar to fit against the newly milled surface

     4) 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.

Fran Cichowski

Southpaw #300 Noank Ct

904 772 4712   capt...@gmail.com

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[Mark Powers La Reina 26C Vancouver, B.C.]

Rob, I am trying to include a photo of the walker (deck fitting ) at the base of the mast. If that does not work here is a link. It is on Cleo in the Nonsuch Photo Gallery  https://pbase.com/nonsuch/image/92163336

Also remember that if you shorten the standing portion of the topping lift you will need to lengthen the running tackle.  If you have 4:1 purchase, one foot shorter on the standing portion is four feet longer on the tackle. It was a fine line on La Reina between making the safety pig tail long enough to allow proper shaping of the sail vs keeping it short enough that it would keep the boom from hitting the bimini arch. If the pig tail is too short the topping lift will keep you from hardening the choker all of the way so you can fully flatten the sail.

Mark Powers

[Rob Cohen "Soave" NS33 Westport, CT]

Fran,

Do you know of a shop that you would trust with this sort of job ?

Do you think the secondary crack at 2 o'clock ( HERE )  is significant enough to develop into a larger problem that might affect the repair strategy ?

Thanks,

Rob

s/v SOAVE

NS33 #009

Cedar Point YC

Westport, CT

[Rob Cohen "Soave" NS33 Westport, CT]

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

 

[Francis Cichowski]

WOW!

That is a fancy bit of hardware

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.

But than that is just me talking

Fran Cichowski

Southpaw NS30U #300  Noank Ct

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[Rob Cohen "Soave" NS33 Westport, CT]

Hi All,

I'd like to thank everyone that contributed to the conversation about the addressing Soave's damaged Mast Fairlead Collar.  The depth of knowledge in this group is incredible.

I've decided to replace the collar.  I was tempted to attempt repair or move to a deck mounted fairlead setup, but for a variety of factors including my limited understanding of metallurgy and naval architecture, I've decided to stick with the known and proven solution.

I've still got lots to learn about Nonsuch boats and will continue try new things that complement Soave's design such as dyneema, composting head, power management, maybe even electric propulsion.

When I get the new collar, I will share pictures of the removal of the damaged collar and installation of the new one.

Thanks again for sharing ideas and sympathy.  

I've rerouted lines so I can sail till the replacement arrives, by rejiggering the 2nd reef tack line.  We're mostly day sailing these days an it's unlikely we'll go out in conditions that might require a second reef.

Thanks,

Rob

s/v SOAVE

NS33 #009

Cedar Point YC

Westport, CT

On Friday, June 20, 2025 at 9:43:14 PM UTC-4 Rob Cohen "Soave" NS33 Westport, CT wrote:

[Rob Cohen "Soave" NS33 Westport, CT]

Hi All,

Just a quick update on Soave's Fairlead Collar.  The new collar and bands have arrived.  Many thanks to Mike Quill for his guidance and quick response.

I am planning to start the install next week and have begin documenting with a Google Album ( HERE ). 

You can check in from time-2-time over the next few weeks to see my progress.  Also feel free to post comments/questions in the album or in our various forums.

Wish me luck....

Rob

s/v SOAVE

NS33 #009

Cedar Point YC

Westport, CT

[Robert Horne]

Please find out the torque values for bringing the two collars together. Either from Mike or somebody on the web. I put a new collar on using 5200 and thought i used the correct torque values. Wrong - the collar has rotated counter clockwise 1” with the halyard as the culprit. Bob Horne. 1989 N26C,  #249, Encore. Pocasser, MA.

Sent from my iPhone

On Jul 10, 2025, at 11:09 AM, Rob Cohen "Soave" NS33 Westport, CT <rob....@gmail.com> wrote:

Hi All,

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[Rob Cohen "Soave" NS33 Westport, CT]

Thanks for the tip Robert.   I'll tighten per Mike's instructions.  

As I understand it, the 5200 is supposed to resist the rotational force of the collar.  Did you remove the collar after it rotated to determine why the 5200 failed ?

Once 5200 cures, it's usually very reliable... maybe you had a bad batch ?

Rob

s/v SOAVE

NS33 #009

Cedar Point YC

Westport, CT

 

[Robert Horne]

No, I did not remove the Collar - YET. Bob Horne  

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From: "Rob Cohen \"Soave\" NS33 Westport, CT" <rob....@gmail.com>
To: "INA-Nonsuch-Discussion-Group" <ina-nonsuch-di...@googlegroups.com>
Sent: Thursday, July 10, 2025 2:02:58 PM
Subject: Re: Damaged Mast Collar

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[Robert Horne]

No. Need to know the torque value and buy some more rubber. Bob Horne

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From: "Rob Cohen \"Soave\" NS33 Westport, CT" <rob....@gmail.com>
To: "INA-Nonsuch-Discussion-Group" <ina-nonsuch-di...@googlegroups.com>
Sent: Thursday, July 10, 2025 2:02:58 PM
Subject: Re: Damaged Mast Collar

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[Robert Horne]

Let me know the Torque foot pound value. Bob Horne

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From: "Rob Cohen \"Soave\" NS33 Westport, CT" <rob....@gmail.com>
To: "INA-Nonsuch-Discussion-Group" <ina-nonsuch-di...@googlegroups.com>
Sent: Thursday, July 10, 2025 2:02:58 PM
Subject: Re: Damaged Mast Collar

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[Rob Cohen "Soave" NS33 Westport, CT]

Hi Bob,

The guidance I got from Mike is :  " Let the glue do it's work. You don't have over tighten the clamps. Most guys break the flanges by over tightening the bolts to stop it from rotating under pressure form the main halyard.  "

Mike didn't specify a specific torque setting.  But he suggested a allen wrench and a open-ended box wrench or socket wrench are the tools to use.  My guess would be 10-12 ft lbs... maybe 15.... pretty light.  They are self locking.

I take that to mean the following :

1. Measure the gap between the bracket faces of the old collar before removing it, maybe make a reference shim to use as a starting point for the new one. ( not to leave in place )
2. Remove old collar.
3. Clean and degrease surfaces to be glued.
4. Get everything aligned the way I want it to end up.
5. Make some pencil marks to make it easy and quick to align once the glue is on the ears.
6. Add glue to ears of the new collar and have a partner hold the two halves up to the mast per marks.
7. Insert screws and hand tighten them evenly all the way around.
8. Use a wrench to tighten to remove all play in the interface between collar and mast, but not so tight that the adhesive is squeezed out.
9. Let it cure.  This may take a day or two depending on temperature/humidity.
10. Return after cured and tighten against the cured 5200.  At this point it may only take only a smidge.  ( like an 1/8 of a turn or less )
11. Check in a week or so after it's been through a couple expansion/contraction cycles.  Confirm bolts are all still snug.

The 5200 has a tensile strength of 700 psi.  The ears each have about 4 sq in surface area.  Getting a good glue joint is critical. 

The whole mechanical system in that area is pretty complicated and dominated by upward and aft forces applied by the turning blocks, I'm not sure how to calculate the rotational force on the collar.

I'll be sure and take lots of photos and will let you know the torque I end up using.

Rob

s/v SOAVE

NS33 #009

Cedar Point YC

Westport, CT

[Robert Horne]

Thanks for the indepth response. Perhaps you can incrementally increase the torque as you take off the old collar. Start with a low value. Bob Horne

Sent from my iPhone

On Jul 10, 2025, at 5:44 PM, Rob Cohen "Soave" NS33 Westport, CT <rob....@gmail.com> wrote:

Hi Bob,

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[Ward Woodruff]

When I first owned my 33, the halyard turning block failed and needed replacement. 

Upon attempting to remove the 5 bolts holding the block in place, I found all stainless steel bolts frozen in the aluminum casting. This necessitated removing the collar from the mast to work on extraction of the bolts. 

There was sheet rubber (neoprene?) as an interface between the collar and aluminum mast. 

Once I successfully replace the halyard turning block, I reinstalled the collar with new neoprene sheet as the interface between the collar and mast. 

Under the load of the halyard the collar rotated on the mast. My temporary solution was to run a lasing from the turning block forward to the Sampson post. That was effective but not elegant.  The final solution was to install thicker, 3/32” (my best recollection but maybe 1/8”) neoprene. 

It seems to me that gluing the collar to the mast with 5200 adhesive sealant may cause future issues when one needs to remove the collar. 

Ward Woodruff

N33 #8 Margery

Niantic Bay, CT

On Jul 10, 2025, at 7:08 PM, Robert Horne <rober...@gvtc.com> wrote:

Thanks for the indepth response. Perhaps you can incrementally increase the torque as you take off the old collar. Start with a low value. Bob Horne

To view this discussion visit https://groups.google.com/d/msgid/INA-Nonsuch-Discussion-Group/13016B3C-47F0-43ED-B7BC-E4F705B25487%40gvtc.com.

[Rob Cohen "Soave" NS33 Westport, CT]

Thanks Ward,

I'm happy I shared my plans, and that we can brainstorm solutions.  Always good to have a plan for future maintenance.

Two thoughts come to mind about about the challenge of releasing the 5200 for future repair. 

1. There is a product reviewed by Practical Sailor ( HERE )  called Debond Marine Formula that is effective at softening 5200 enough to work it loose.  I don't know how deeply it can penetrate a joint that I'd be creating between Soave's mast and collar.  ( about 2" oval  )
2. I have read that 5200 softens between 140º F and 190ºF I think most Aluminum alloys would be OK under 250ºF.  So heat may be an option.

Does anyone have experience with 5200 and aluminum ?

I'll circle back with Mike Quill also since he's probably had to work with this exact scenario before. ( the 5200 came from his install instructions ). 

Thanks,

Rob

s/v SOAVE

NS33 #009

Cedar Point YC

Westport, CT

[Brian Godfrey]

   The failure may have been caused by the paint on the mast.  Shear strength is what you are relying on when you put the 5200 on the fairlead collar ears to keep it from rotating.  5200 has 390psi shear strength on aluminum, meaning that one square inch of the glue placed between two pieces of aluminum it will resist 390 pounds of shear (sliding) force.  Some substrates offer considerably less. The 5200 data sheet doesn't spec shear strength for any paint, but I think a mast freshly painted with two part paints should offer similar shear strength to FRP and that would be about 360psi. So using 5200 between the aluminum fairlead collar and a well painted mast should give you 360psi shear strength. But poor quality, improperly applied, or just plain old paint might offer considerably less. 
   You'll put more than 1 sq in of 5200 on each ear - or it will squeeze out to more than that, anyway.  So unless you over harden the halyard by a lot, it should hold extremely well on good mast paint. If you over tighten with that big powerful electric winch then something bad is going to happen.  In my experience (the PO apparently did just that) having the glue come loose is about the least bad thing you can hope for.

Brian Godfrey
Vela, NS33, San Diego

-- Brian Godfrey

[Francis Cichowski]

DO NOT USE A TORCH!

You could be pretty safe with hot water .

Build a closed pot around the mast and keep adding , say 150f, water until temp stabilizes at desired level.

I would try it on some 5200 and two al pieces in hot water first.

Fran Cichowski    capt...@gmail.com

Southpaw N30U  #300

Noank, Cty

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