Mast failures

[Captain Greg]

Hi Nonsuch sailors,

I would like to start a thread to collect info on Nonsuch mast failures - I think we all need to be aware. We had one in our weekly Wed night race in Cape Breton this week.

I am trying to help the owner who is not an INA member, to figure out how to deal with this. We have found a salvage aluminum mast, so there is a potential easy solution...... i won't go any farther on this as it is underway with insurance, adjusters and all....

I am interested to know more about other known aluminum mast failures. In my research since my friend's incident last Wednesday, I found a thread (in our Google discussion group) about a UK owned Nonsuch 30 that had a sudden breakage at deck level, while sailing. Bang, and it was down. No damage or human injury otherwise in either event. (c.2009 I think). In the 2009 incident, insurance company declined to cover, due to fine print: 'gradual corrosion causing crystallization of the aluminum, due to to contact with Stainless steel clamp that slid off,'.... resulting in reduced tension strength..... Insurance does not usually cover wear and tear and gradual degradation...etc....

The insurance company cited corrosion of the aluminum due to contact with stainless steel. based on their engineer's report that cited crystalization indicates reduced tensile strength.

---------------

My observations: 

- the 2009 incident cited specifically, as it had the severed top part above deck, and the stub below for the adjustors to see: there was corrosion due to ss contact with aluminum, due to slipping of one of the bands from its insulation, just above deck level. This corrosion causes crystalliization of the aluminum over time, which has a negative effect on the tensile strength of the mast.

- I saw another result at Green Turtle Key, Nonsuch 30U, was stored on the hard with mast up during a hurricane, mast sheared at the deck. Was repaired with a spline. This boat was discussed on our Google discussion group by owner, and was on sale on our INA site. Recently sold. I had the chance to see it while cruising there and considered buying it, but did not.... My wife thinks I have too many boats now....

in the attached photo, you can see the exposed edge of the stub of my friend's mast, and it looks crystalline. From what I have read recently, this indicate lack of tensile strength. I am not a metallurgics expert by any means.... just an observer.

--- if any of you have any knowledge of mast failures like this, please post to this thread. There may be symptoms to recognize on the surface if there is corrosion that might cause such a failure, and preventative measure that can be taken to renew the 'isolation' between stainless and aluminum on your masts.

Greg Silver

Misty Cat 26C #121

Cape Breton

[Ward Woodruff]

The failure in the photo here was likely due to unnoticed cracks below the top of the deck ring. 

I am not an engineer but I believe that is approximately the location of the maximum bending stress. 

If the mast is left installed for extended periods, like on shore over the winter year after year, it will be difficult to see a problem (crack) developing

In the fall of 2000, my Nonsuch 33 suffered a mast failure at the joint. The upper section tore from a bolt hole. 

I was fortunate: 

The failure occurred on the way to the boatyard for the winter, no injuries to crew. 

Towboat US showed up 10 minutes later without invitation (I am a member) and guided us under our own power to a dock where Towboat helped us get the sail off. 

I sent the report, photos and estimate for a new carbon fiber mast to my insurance company by email.  They replied “okay” 1/2 hours later. 

It took over 8 months to get the replacement mast as the designer/builder was transferring the equipment from his place in Concord, MA to the new builder, Moore Brothers in Bristol, RI during COVID. 

Top- Failed mast on arrival at boatyard -Oct 2020

Above- New mast at builder - June 2021

Below - Self transporting on borrowed 8 man rowing shell trailer

Out of pocket, I happily bought a new sail to fit the new mast bend. 

Subsequent to my failure, a 36 at my yard discovered a deck level crack in his mast.  As I understand it, after some pleading, his insurance company at least helped him with an aluminum mast replacement.  His replacement was from Klacko. 

Ward Woodruff

N33 #8 Margery

Niantic Bay, CT

On Aug 25, 2025, at 1:45 AM, Captain Greg <gregca...@gmail.com> wrote:

Hi Nonsuch sailors,

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[Rob Cohen "Soave" NS33 Westport, CT]

Hi Greg,

I like your idea of collaborating to accumulate relevant information that would guide our maintenance efforts.  Mast & wishbone is an excellent place to start.

My efforts on Soave have been focused on detection and remediation of problem areas, but the effort can be overwhelming.  Knowing what I know now, I would approach purchasing a NonSuch differently. Close up inspection of mast and wishbone is necessary to properly assess value because remediation is time consuming and replacement is close to the value of the entire boat.

I'm in the process of purchasing a winter cover and contemplating  a $455 option for the flexibility of wintering with mast up or down.  I'm seriously considering skipping the option because having the mast down in the winter allows me to see and address many early stage issues.  Plus while working on Soave in the yard I could observe the stresses on boats stored with their masts up.  A boat in the water moves slightly and heels to dampen the effect of strong wind gusts.  On the hard boat doesn't move and the spars are flapping in the breeze.

Regarding the photos.  The failure looks to be in close proximity to the deck collar where the wedges are set.  On my NS33 there aren't any stainless fittings in that vicinity, so I'm thinking the cause of the crystallization would be something other than the effect of dissimilar metal corrosion.   Maybe stress fatigue cracks that were missed during inspection.

Rob

s/v SOAVE

NS33 #009

Cedar Point YC

Westport, CT

[Mike Quill]

Hi All

 Studying the picture, I'm curious to know the starting point of the failure. The fact that the mast has the original half moon fairlead collar ( rather than the wrap around style ) indicates  an early boat number. It does look like a replacement bottom section (1/4 wall thickness) so that is good. 

When we did the mast bottom replacement program, the yards were instructed not to drill through the mast  to install the deck pin but rather connect the mast hold down kit supplied. Sadly, some yards did not get the memo.  I don't see the deck pin here in the picture. Another plus. BUT I can't determine if a hole is not in the mast. 

It's possible everything was done right and no holes in the mast and this is simple fatigue left unchecked by leaving the mast up every year? 

Cheers 

Mike Quill  

On Monday, August 25, 2025 at 1:45:42 AM UTC-4 Captain Greg wrote:

[John Barbour - Nature 26U Toronto]

Being a metallurgist, I think the term crystallisation is wrongly applied in terms of the mast failure.

 Stainless steel and aluminum galvanic corrosion is often seen in damp areas, especially in salt water environments.  During the corrosion process, the aluminum surface oxidises, which is evident as a white powder. Over time the surface becomes rough and pitted.  Deep pitting will  weaken the mast in that area, and as the mast flexes in normal use, a crack can be initiated.  Over time, this tiny crack, known as a fatigue crack, will grow, until the mast fails.  The metal in the area did not fail by crystallisation; it become weaker, and susceptible to failure,  due to the pitting. 

As Mike Quill says, a hole or excessive flexing of the mast, can cause a crack followed by mast failure,  This is exactly the same problem as deep pitting; a small crack forms, then grows and brings down the mast.

On a historical note, back in  the 1950's, fatigue cracks were erroneously thought to be caused by the atoms in the metal rearranging themselves into loose crystals, like salt. and becoming very weak. 

John Barbour

Nonsuch 26 "Nature"

Toronto

[Greg Silver]

John, its great to know there is a metallurgist aboard! Thank you for clarifying the matter of oxidation, pitting, fatigue and failure......My comment about the 'crystallization' was taken from the 2009 incident, using the insurer's words, from their response which denied the claim. Seems to raise some questions about the integrity of the insurer.

Greg Silver

Misty Cat 26C #121

Cape Breton

[Thor Powell, Nonsuch 26, Victoria BC]

I ha e always been told that leaving the mast in when on the hard for any extend period is a poor idea.  A boat and mast are designed to move together. 

It is as mentioned an older mast with several holes near the deck, but no close to the failure.  Possibly a defect in the material from the get go.. Maybe a  stress event in the distant past.  

Mast inspections are a challenge, other visual check and maybe painting blue reviewing liquid in critical areas not much you can do.  The mast joint however deserves close inspection as if that join come the least bit loose it will fail and there is a revised attachment method .

As for the older mast with screw in  block and  sail attachments , maybe they should be up graded to the newer strap configurations. 

That said  I have need more mast failures on traditional rigs than Nonsuchs'  it  a risk for all sailboats. 

I think that Klacko has a mast that was never installed in their shop, give Danny a calll

[newelljc9]

Mascouche still has her original 1981 mast which was modified when it became clear that one cannot drill into the lower section of the mast. I believe it was found that the lower 10' should be free of drill holes. All the early Nonsuches were upgraded to having a tie down to replace the pin at deck level. Jorgen Moller and I did replace the bolts at the mast joint with Mike Quills upgrade in 2011. The original fittings were showing wear.

While on a cruise to Whitby, Ont. I was battling the aftermath of a hurricane that produced short steep seas that had the run of Lake Ontario from Rochester. Mascouche was behaving well under the circumstances under a single reef beating to windward. One was very conscious of the "whipping" of the top of the mast. It became too much for the weather vane which flew off. The constant flexing of the mast must eventually fatigue the metal at the deck area. In addition, it makes light air sailing in a swell very annoying. The wishboom tends to rock about spilling what wind there is. I mitigated these issues with the standing gaff rig. The gaff sheet steadies the mast and prevents it from whipping. I see no reason why yachts with standard wishbooms do not add add a backstay. It should add years to the life of the mast. I will leave it to our metallurgists to determine how much longer life one can anticipate. Anyway an inexpensive dyneema backstay should improve the enjoyment of sailing in light airs. Those with boom clearance issues or extended booms might require a bumpkin to provide sufficient clearance for the boom.

An upgrade that should extend mast life would be to replace the heavy aluminium boom with a carbon fiber one.

John Newell

Mascouche 26C1

Toronto

Photo taken by Doug Farrand on Quetico 30U #368. The "backstay" is actually the gaff sheet which allows the gaff to be trimmed to the breeze at the top of the mast. On Lake Ontario this can be substantially different to what is happening on the water. JN

On Monday, August 25, 2025 at 1:45:42 AM UTC-4 Captain Greg wrote:

[David Darmstadter]

Mast failure to comment

Sent from my iPhone

On Aug 26, 2025, at 1:19 PM, newelljc9 <newe...@gmail.com> wrote:

Mascouche still has her original 1981 mast which was modified when it became clear that one cannot drill into the lower section of the mast. I believe it was found that the lower 10' should be free of drill holes. All the early Nonsuches were upgraded to having a tie down to replace the pin at deck level. Jorgen Moller and I did replace the bolts at the mast joint with Mike Quills upgrade in 2011. The original fittings were showing wear.

While on a cruise to Whitby, Ont. I was battling the aftermath of a hurricane that produced short steep seas that had the run of Lake Ontario from Rochester. Mascouche was behaving well under the circumstances under a single reef beating to windward. One was very conscious of the "whipping" of the top of the mast. It became too much for the weather vane which flew off. The constant flexing of the mast must eventually fatigue the metal at the deck area. In addition, it makes light air sailing in a swell very annoying. The wishboom tends to rock about spilling what wind there is. I mitigated these issues with the standing gaff rig. The gaff sheet steadies the mast and prevents it from whipping. I see no reason why yachts with standard wishbooms do not add add a backstay. It should add years to the life of the mast. I will leave it to our metallurgists to determine how much longer life one can anticipate. Anyway an inexpensive dyneema backstay should improve the enjoyment of sailing in light airs. Those with boom clearance issues or extended booms might require a bumpkin to provide sufficient clearance for the boom.

An upgrade that should extend mast life would be to replace the heavy aluminium boom with a carbon fiber one.

John Newell

Mascouche 26C1

Toronto

<image0.jpeg>

Photo taken by Doug Farrand on Quetico 30U #368. The "backstay" is actually the gaff sheet which allows the gaff to be trimmed to the breeze at the top of the mast. On Lake Ontario this can be substantially different to what is happening on the water. JN

On Monday, August 25, 2025 at 1:45:42 AM UTC-4 Captain Greg wrote:

Hi Nonsuch sailors,

I would like to start a thread to collect info on Nonsuch mast failures - I think we all need to be aware. We had one in our weekly Wed night race in Cape Breton this week.

I am trying to help the owner who is not an INA member, to figure out how to deal with this. We have found a salvage aluminum mast, so there is a potential easy solution...... i won't go any farther on this as it is underway with insurance, adjusters and all....

I am interested to know more about other known aluminum mast failures. In my research since my friend's incident last Wednesday, I found a thread (in our Google discussion group) about a UK owned Nonsuch 30 that had a sudden breakage at deck level, while sailing. Bang, and it was down. No damage or human injury otherwise in either event. (c.2009 I think). In the 2009 incident, insurance company declined to cover, due to fine print: 'gradual corrosion causing crystallization of the aluminum, due to to contact with Stainless steel clamp that slid off,'.... resulting in reduced tension strength..... Insurance does not usually cover wear and tear and gradual degradation...etc....

The insurance company cited corrosion of the aluminum due to contact with stainless steel. based on their engineer's report that cited crystalization indicates reduced tensile strength.

---------------

My observations: 

- the 2009 incident cited specifically, as it had the severed top part above deck, and the stub below for the adjustors to see: there was corrosion due to ss contact with aluminum, due to slipping of one of the bands from its insulation, just above deck level. This corrosion causes crystalliization of the aluminum over time, which has a negative effect on the tensile strength of the mast.

- I saw another result at Green Turtle Key, Nonsuch 30U, was stored on the hard with mast up during a hurricane, mast sheared at the deck. Was repaired with a spline. This boat was discussed on our Google discussion group by owner, and was on sale on our INA site. Recently sold. I had the chance to see it while cruising there and considered buying it, but did not.... My wife thinks I have too many boats now....

in the attached photo, you can see the exposed edge of the stub of my friend's mast, and it looks crystalline. From what I have read recently, this indicate lack of tensile strength. I am not a metallurgics expert by any means.... just an observer.

--- if any of you have any knowledge of mast failures like this, please post to this thread. There may be symptoms to recognize on the surface if there is corrosion that might cause such a failure, and preventative measure that can be taken to renew the 'isolation' between stainless and aluminum on your masts.

Greg Silver

Misty Cat 26C #121

Cape Breton

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[Captain Greg]

HI John, and everyone

Given the comments and some more history about mast failures at deck level, I took a look at my mast which is on sawhorses in my yard at the moment.... and I am concerned about what appears to be 'pitting' in that area adjacent the deck partners, along with some abrasions (from getting knocked during 40 years of stepping/unstepping I presume?). Also where you see the red arrow pointing there are some 'imprints' of perfect circles about 6mm in diameter which are puzzling. You will have to really enlarge this pic to see these little circle outlines.

I'm interested to hear from you, and anyone else, if this pitting looks like serious corrosion. My first mate thinks it might be a good idea - if its even possible - to insert a tight-fitting aluminum spline inside the mast in this area to reinforce it?

Thanks for any input!

Greg Silver,

Misty Cat N26C #121

St. Peter's, Cape Breton

[Brian Godfrey]

   You should contact Mike Quill about it.  He advised me on repairs when I found pitting beneath my tack collar.  There are specifications for how deep the pits can be and still be safe, but you should ask him because the spec might be different for the area right next to the deck, it being right at the fulcrum.  Mine was well within spec and I followed his instructions on repair.  You are lucky your mast is on sawhorses!  The prep involves sand blasting which is very difficult to do in a nice marina.

--Brian M. Godfrey
  br...@wildbirdshop.com

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