The Offshore Voyaging Reference Site

GMT Carbon Mast, Problems

Okay, this is a big one and to fully understand it will take you a lot of reading. But, if you are contemplating a major custom project, such as a new mast or even a new boat, the time expended here may save you a lot of money and aggravation.

We made a lot of mistakes on this one that you definitely don’t want to emulate. We have listed the lessons we learned at the end and have marked the text at the points where we learned each lesson.

If you don’t feel like reading more than 4000 words to find out what happened, just skip to the Outcome and  Lessons Learned sections, which alone could save you a bundle.

To keep the length of this just a little shorter than War and Peace, we have not included the supporting reports in the body of the text, but they are available by clicking on the links.

The Problem

When we got to North America in the fall of 2003, our aluminum mast was on its last legs after 130,000 miles of sailing, much of it tough; so we added a new mast to the to-do list for the full refit we were planning. Originally, our thought was to just buy another aluminum tube and transfer the gear and rigging, but after some research it became obvious that there were some real advantages to going with carbon fiber:

  • For boats our size, the price difference is no longer that great when compared to the potential increase in resale value of the boat.
  • Greater stability and resistance to capsize.
  • Reduced pitching.
  • The potential to build a far stronger mast than would be possible in aluminum.
  • Increased stiffness, reducing the need for running back stays in all but heavy winds and seas.

Our first step was to consult with Jay Maloney of Maloney Marine Rigging in Booth Bay, Maine. Jay has been doing our rigging work for 15 years and we have a huge amount of respect for his skills and integrity.

After receiving a high estimate from Offshore Spars, Jay advised us to focus on GMT Composites of Bristol, Rhode Island, suggesting that as a smaller custom shop they would be more focused on our needs and probably cheaper than a big outfit like Hall Spars or Offshore Spars. We agreed. (Lesson #1)

We visited GMT Composites and spent several hours going over our needs for a bombproof and simple mast for high latitude sailing with Will Rogers, salesman, and David Schwartz, chief engineer and CEO of GMT. We also presented a multi-page specification, which was to be part of the agreement between the parties.

After several weeks of negotiation we agreed a price and sent in our deposit based on the GMT Composites proposal. A few days after that Will Rogers sent us GMT Composites’ standard contract. This was the first time we had seen or heard anything about this contract, which was in our opinion very one-sided in GMT Composites’ favor and sent after GMT Composites had solicited and accepted our deposit. We refused to sign the agreement because:

  • In the event of a warranty repair after sea trials (undefined term) we would be responsible for un-stepping the mast, shipping it back to GMT Composites, shipping it back to the boat and re-stepping it. Under this clause even a small warranty repair could cost us thousands.
  • We were required to pay GMT Composites the entire amount prior to shipping but 100% of title would remain with GMT Composites until the mast left their plant.
  • The agreement stated that it was the entire agreement between the parties, effectively making our specification and the GMT Composites proposal meaningless.

In the end it was agreed that we would not sign the agreement and that the GMT Composites proposal and our specification would constitute the agreement between the parties. (Lesson #2)

We were somewhat comforted by the article about our new mast in Carbonics, GMT Composites’ news letter, that stated: “…Phyllis Nickel and John Harries…are committed to high latitude short handed sailing and [Morgan’s Cloud‘s] new carbon mast will be designed to take anything Mother Nature sends her way…”

At least, we thought, GMT Composites clearly understood and were committed to building us a mast that we could have confidence in, even in the most extreme conditions in the high latitudes. (Lesson #3)

We were also comforted by our assumption that GMT Composites was part of Eric Goetz Custom Boats who have a great reputation (including a very positive experience related to us by a friend) for making problems right. (Lesson #4)

The design phase progressed over several weeks with David Schwartz being flexible and appearing to listen to and incorporate our needs and requests.

We assumed that all was well until we made a visit of inspection to GMT Composites and found a whole list of worrisome problems, the worst being that the storm trysail track ended where the technician discovered that he could not bend it around a winch. Worse still, it was attached to the mast with no backing plate through just .16” of carbon. David Schwartz assured us, with the help of graphs, that the storm trysail attachment was adequate, despite the fact that both the mainsail and spinnaker pole tracks had backing plates. Even though we were not convinced, the mast looked beautiful in its brand new coat of Allgrip and we wanted to go sailing. Meetings were held and compromises made, we were assured that if there were any problems GMT Composites would stand behind their product, and so we paid the full amount. (Lesson #5)

The mast was shipped to Maine and we started to rig it. Very soon it became apparent that the technicians who put it together had made a lot of mistakes: Halyard messengers were not just tangled, but knitted; wires were mislabeled; nylon sheaves were ground to fit and installed complete with grinding debris; and on and on. We spent two days correcting as many of these errors as we could and documented them on the first defect list.

Jay Maloney arrived for the stepping and in it went. Immediately a glaringly obvious new problem became apparent: The spreaders were out of line with each other and the shrouds. And not just a little. We were to find out later that the port lower spreader was over 11” further forward than the starboard one. From abeam poor Morgan’s Cloud looked like a car that has had a smash and not been repaired properly. Now think about this for a moment: The best parallel I can come up with is buying a brand new luxury car (the price is about the same) and finding that the chassis is bent.

Jay Maloney called David Schwartz at GMT Composites and suggested quite forcefully that he needed to come and have a look, which he did, bringing a technician with him. David spent two hours checking the mast and finally stated that it was a trivial problem of misaligned spreaders that could be fixed in the fall and that the boat was safe to sail. He later billed us $4138 for this visit. We did not pay it.

We were worried and upset, but GMT Composites had our money. It was either take their word for the safety of the mast or write off the season. David Schwartz assured us once again that he would stand behind his product. We went sailing and circumnavigated Newfoundland. On that cruise of some 3000 miles, other problems surfaced and we made a second defect list.

We submitted the list to David Schwartz, who dismissed most of our concerns and suggested fixes to many of the others that we were less than happy with. Now what? Finally we suggested arbitration. We would split the cost of an independent survey and recommendations would be binding on both parties. David accepted in principle, but only if the surveyor was someone from a list of three that he submitted.

Though neither Jay nor we were totally comfortable with this scenario, we finally agreed to appoint Chuck Poindexter, owner of Sound Rigging, in Essex, Connecticut, a rigger from David’s list. (Lesson #6) Chuck stated that he could do an adequate survey with the mast in the boat. (Lesson #7) He came to Maine and spent about four hours inspecting the mast including going up it in a bosun’s chair. David Schwartz of GMT Composites and I both made submissions to Chuck and then counter-submissions. Chuck completed his report, which basically stated that the mast was OK with some small defects. We were not happy but had to abide by it.

Now that Chuck had assured us that all was fundamentally well with the mast, our biggest concern was the lack of a backing plate for the storm trysail track, which he had given a pass to. I spoke with an old friend who is one of the most experienced composite boat builders in the world and has also been involved in the building of masts for the Americas Cup Class. He stated that there was no way that the attachment was adequate. We decided to fix the things we were not happy with in Chuck’s report at our own expense and get on with our lives. (Poindexter did admit in a later e-mail that he might have been wrong about the track fastening.)

Our next challenge was to get the spreaders on straight. Since GMT Composites had made such a large error when building the mast, we had no confidence in their ability to fix it. So Jay Maloney and I came up with a simple way to get the spreaders set correctly using a laser transit and a tool that I made from a set square. But with the tool installed it soon became obvious that the tube was twisted. Jay Maloney, with my assistance, measured and reported the twist at 7.8 degrees in 60’7” and we estimated that the total twist was about 10 degrees from heel to cap.

Both Jay and I assumed that with this discovery GMT Composites would either replace the mast or give us our money back. David Schwartz refused to do either, stating that the mast was okay and suggesting that he would pay to enlarge the partners (hole in the deck) in our aluminum boat so that the mast could be installed skewed to compensate for the twist. We rejected this solution on the grounds that it was not reasonable to modify our boat that is true to accommodate the mast GMT Composites built that is twisted. He then stated that the best he was willing to do was fill the holes in the spreaders with weld bead and re-drill them to compensate for the twist.

It was time to examine our options and get an accurate idea what all this was going to cost us before putting any more money and time into a mast that we had lost confidence in.

We contacted Hall Spars, of Bristol, Rhode Island and Composite Solutions of Hingham, Mass. Both were interested in the project and visited the GMT Composites mast. Both expressed surprise and concern at the thin walls of the tube, echoing doubts my boat builder friend, who had advised us on the storm trysail track, had expressed. Now we had a whole new set of worries. Maybe the basic mast was inadequate.

However, obviously neither Hall Spars nor Composite Solutions was exactly unbiased. We clearly needed someone who knew carbon masts and had no axe to grind. One name kept coming up: Dirk Kramers, one of the most experienced carbon composite engineers in the business. This is the guy that figures out how to put the Alinghi Americas Cup yachts together. We suspected that we could not afford him, but his colleague, Steve Koopman, was willing to run the numbers on the mast for a very reasonable $1500. It hurt to throw more money at this mast, but we had to know. GMT Composites agreed to share the necessary information with Steve, although they did charge us $400 to do so.

Steve Koopman filed his report. On the surface, the mast got a pass, but with some very worrying qualifications, most notably:

This approach gives a theoretically lighter solution but results in a somewhat less robust mast. We would not normally specify a tube with the proportions of section size to wall thickness that this mast features, but more extreme examples have certainly been built. The tube laminate does not exhibit the interleaving of off-axis fiber that is commonly found in masts and that we would specify in our designs. In addition, the laminates are constant from top to bottom so are not optimized weight-wise to the expected stresses in the mast. The twist in the tube is a clearly visible defect in the mast, but not likely to cause it to fail. The items mentioned in this paragraph are subjective and different spar manufacturers and designs will end up with different solutions.

Our next problem was that, having repeatedly gone on record as having reservations about the mast and given Koopman’s qualifications in his report, we had a legal and moral responsibility to share the report with our insurance underwriters, Pantaenius. Their technical department read the report and rejected the mast stating:

Whilst insurers have not examined physically the mast provided by GMT they have had the benefit of considering the report produced by SDK and taken a view based upon its findings against what they understand to be the intended use of the yacht which is blue water cruising in geographical areas where severe weather conditions are encountered frequently. The insurers have considered the evidence concerning the mast ‘as designed’ and not ‘as built’. Whilst insurers are in broad agreement with the findings contained in the SDK report which is underpinned by Finite Element analysis they consider that the factors of safety designed into the mast are below that which they would be prepared to accept as a reasonable insurance risk when encountering the expected severe weather conditions in remote areas. Insurers have taken the view that the factors of safety designed into this monolithic structure are more performance orientated than they are comfortable with. In view of this assessment and in relation to the beneficial consequential loss cover afforded by the Pantaenius Yacht Hull Clauses the potential risk is not considered reasonable to the insurers of Morgan’s Cloud and consequently they are not able to offer terms for insurance purposes.
The view of the insurers has not been influenced by the apparent twist in the mast nor the novel design however, when considered in relation to the identified factors of safety these issues would only serve to reinforce the perceived view that the risk of failure and consequential damage is higher than they would be comfortable with given the intended use of the yacht.

After reading Pantaenius’ position, Koopman of SDK Structures came back with an addendum to his report.

The Outcome

As so often happens in boats and life, things were not as clear as we would have liked. Nonetheless, after much thought, we decided to buy another new mast, this time from Hall Spars. (Not an easy decision since we were spending capital that took a lot of years to accumulate and that we got from the sale of our house.) Our reasons were:

  • The largest and most experienced insurer of offshore sailboats in the world rejected the GMT Composites mast for hard usage in the high latitudes. As far as we know, Pantaenius are the only company that will cover us for the kind of sailing we do. Keeping this mast meant no insurance cover.
  • We had bought a new mast in the first place, not to get better performance, although that was a nice side effect, but to get peace of mind. It wouldn’t matter what we did in the future, the problems with the GMT Composites mast would always have us wondering what else might be wrong. Koopman only gave the mast a pass ‘predicated on the tube laminate being properly applied, consolidated, and cured’. Was it? There was no way to know. Neither of us wanted to spend the rest of our cruising life looking up at a twisted mast and wondering what else might be wrong.
  • Both Hall Spars and Composite Solutions specified masts for our boat that have much thicker walls, albeit with smaller sections, than the GMT Composites mast, before taking into account our rough use.
  • Koopman expressed reservations about the thin wall, large diameter approach in his report.
  • Both Hall Spars and Composite Solutions use 45 and 90 degree off-axis laminates to bind the mast together. I was informed by Hall that the application of these off-axis laminates is the most labor intensive part of the lay-up process. GMT Composites only used a few 60 degree laminates and did not interleave them between the vertical laminates. Maybe that is okay, but why are Hall and Composite Solutions taking these costly steps in the highly competitive composite mast business? We suspect they have good reasons.
  • The day will come when we wish to sell Morgan’s Cloud and the twisted GMT Composites mast with all the question marks hanging over it will undoubtedly reduce the value of the boat substantially.
  • Fixing the GMT Composites’ fitting attachments, correcting the lead problems and fabricating four new spreaders to compensate for the twist would cost us many hours and several thousand dollars.

The bottom line: We take our boat to hazardous places and were not willing to trust our lives to the mast built by GMT Composites.

Lessons Learned

  1. Get the right references and advice.
    We have a huge amount of respect and personal regard for Jay Maloney; however, we should not have taken his recommendation of focusing on GMT Composites without doing our own due diligence. At the time, Jay had not installed many carbon masts. We should have interviewed other riggers and boat builders with more carbon fiber mast experience.
    We need to make clear here that this was our fault, not Jay’s. He was up front about his lack of carbon mast experience. We would not hesitate to recommend Maloney Marine Rigging. In fact we do. Also, Jay expended countless hours over 20 months trying to make this situation right that he has never billed us for. Thank you, Jay.
  2. Stop the process when it first starts to go wrong.
    In future, if a company does something like only showing their contract after they have received our deposit, we will pull the order. No ifs, buts or maybes; even if we are forced to forfeit our deposit, we will walk. Despite agreeing to not impose the standard contract, David Schwartz of GMT Composites repeatedly cited its clauses when things started to go wrong.
  3. Don’t be comforted by marketing material.
    We were comforted by the Carbonics quote, but news letters are marketing tools. In the future we will completely discount marketing hyperbole in our selection process. Was the GMT mast capable of “tak[ing] anything Mother Nature sends [its] way”? We can’t know for sure, but Pantaenius doesn’t seem to think so.
  4. Do your due diligence.
    Being comforted by assuming we were doing business, however indirectly, with Eric Goetz was stupid. A couple of phone calls would have told us that GMT Composites and Eric Goetz had parted ways well before we ordered our mast, leaving David Schwartz as sole proprietor at GMT Composites.
  5. Don’t make the final payment until you are really comfortable, no matter what it costs you.
    We should have refused to pay the final amount once we became uncomfortable with the mast and GMT Composites’ level of commitment to fix it to our satisfaction. However, this is easier to say than to do. We had already paid well over half of the purchase price and a prolonged fight would have cost us the sailing season and perhaps everything we had in the mast. Still, we should have hung tough. By letting our desire to go sailing influence our decision we surrendered our last vestige of control over the situation and became completely dependent on David Schwartz’s willingness to accede to our wishes.
  6. This highlights a general problem in the marine industry: ‘No cash, no splash’ has become the standard.  We, the customers, have in many, perhaps most, cases surrendered our right to adequately test custom products and work before making the final payment on them. At the very least we should insist on retaining clauses, like those common with custom-built houses, in which the owner retains an amount of money against defects for a reasonable period. This amount could even be held in escrow to prevent the customer from taking unfair advantage of the vendor.
  7. Make sure any arbitrator is a qualified surveyor, or better still, a qualified arbitrator. Don’t use an industry insider.
    On the surface, this one was really stupid. But on the other hand, by this point we were basically powerless. GMT Composites had all our money and was not willing to make changes and repairs to the mast to our satisfaction. David Schwartz would only accept arbitration if the arbitrator came from his short list. Basically, we had nothing to lose.
  8. Don’t take the easy way out when you know it is wrong.
    Deep down, I knew that agreeing to have Chuck Poindexter survey the mast in the boat was a bad idea. It could be argued that it was Chuck’s responsibility as the professional rigger to reject surveying the mast in the water, but that does not alter the fact that I succumbed to the easy way out. If he had surveyed the mast out of the boat, he could not have missed the twist.
  9. If you have experience, trust it.
    Over and over again through this process I let the professionals convince me that my gut feelings of discomfort were unfounded. For example, when I questioned the storm trysail track fastening, David pulled out a graph showing fastening strength into carbon and convinced everyone round the table, including Ian McCurdy of McCurdy and Rhodes, designer of Morgan’s Cloud, and Jay Maloney, that it was okay to fasten our last line of storm defense into less than 3/16” of carbon despite the fact that carbon, by David’s own admission, has about one half the screw holding power of aluminum. I was uncomfortable, but I went along with the professionals.
    In deferring to the professionals, I completely forgot that I have sailed more offshore miles than all of the people around that table put together. I forgot that I have been hands on maintaining offshore sailing boats and fixing what breaks at sea for 35 years. I should have remembered that. I knew that fastening the track without a backing plate was wrong, but I let my inability to say why in engineering terms handicap me. (Incidentally, my boat builder friend later gave me the engineering facts that make David’s graph incorrect when applied to the trysail track. They are to do with cycle loading.)
    The point is that if you are an experienced offshore sailor and something looks wrong to you, it probably is, even if you can’t articulate why. Don’t let the professionals convince you otherwise using engineering theory that may not apply to your particular situation. Remember, they will be at home in a nice warm bed when the item that made you uncomfortable blows up in your face, probably on a dark night when it is blowing like blazes.
  10. Don’t be reassured by the ‘it has worked on hundreds of boats in the past’ argument.
    Over and over again through the years marine professionals have suggested that Phyllis and I are unreasonable in demanding the level of attention to detail and strength that we expect for anything that goes on Morgan’s Cloud. This frequently came up during the mast saga.
    We constantly remind ourselves, particularly after this experience (and you should too if you plan to go offshore), that only a tiny minority of boats actually go anywhere that really tests them. This is particularly true on the eastern seaboard of the USA where the conditions are generally benign. Don’t believe me? Walk through a marina in England or New Zealand and look at the boats. Look at how much shorter the masts are. Look at how much heavier the gear is relative to the size of the boat. If you plan to go offshore, high latitudes or not, don’t let the professionals talk you into systems because they work for boats on Long Island Sound or on a June trip to Bermuda every couple of years.
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Dick Stevenson

John, What a saga about the cf mast. I am sorry. At some quiet moment could you do an update on living with your Hall Spar cf mast. It sounds like you must have 5-6 years now. I am particularly interested in MC’s performance changes, maintenance issues and whether you have found any longevity concerns. Thanks, Dick Stevenson, s/v Alchemy

Dick Stevenson

John, Thanks for the heads up on those articles I had yet to find. Dick

andrew kledzik

i enjoyed the article. always enjoy reading “lessons learned”.
i am a masters student in ocean engineering and loved your ability to recognize that your experience should mean something, regardless of what the theory and calculations may point to.
i am a weekend sailor currently in florida, building towards the life.
hope to see you out there someday.
andrew kledzik


As a procurement professional this story has proved captivating. I have one question left: Ignoring all the costs of putting it right how did the originally agreed purchase price of the GMT mast compare to the purchase price of the Hall spar?

Jim R

Can you give some detail on how the process went with Hall Spars? How did the contract, payments, and warranty support differ from GMT? Can you post a copy of the Hall Spars contract and your specification for that mast? Would you recommend them again for a custom carbon fiber mast? Would you recommend Jay for carbon fiber mast rigging now?

Steven Schapera

Reading this article highlights a common problem in business: “Avoiding surprises”. With the benefit of hindsight, the real lesson seems to be that BEFORE handing over a deposit, establish the “rules of the game” and agree to the terms of a Contract. If one hasnt been discussed, DRAFT A NEW ONE, at least covering key terms. If that had been the first step, the rest is most unlikely to hava happened – you wouldnt have agreed to their Contract, and you would have gone elsewhere. I’m quite sure that in your business career you would never have enetered a transaction of this magnitude with FIRST agreeing terms.
Considering the amount $ involved, did you ever consider taking legal action? I would have thought your case would be very strong.

Steven Schapera

All noted, thanks. I guess you are right – in this case the other party had no intention of ever giving you something that all could be proud of, it was more of a race to get your cash and then give you the bare minimum after. Thanks for sharing.

Roger Patterson

An interesting and insightful article, notes and comments.

It would be interesting to know the nominal dimensions, scope of the build and work, and costs of the CMT Composites and Hall Spar masts, whether just dated or adjusted for inflation.

There is generally a shortage of such cost information available. Although such information is generally very specific, it is nonetheless insightful. The reader has to appreciate that a 10 ~ 20% difference can be due to the scope of installation (undress, redress), other installation issues and more if de-rating allowable stresses, or similar, to ensure a suitably robust design.

Thank you.

del monaco michele

I’m the proud owner of a 1977 Alpa 11.50 sloop that belonged to an old friend of mine who has just died. In October I knocked down the mast to change the shrouds and, with the mast on the ground on trestles, while I was dismounting the shrouds, it fell from the trestles to the ground pivoting on the right spreader .
Once placed on the trestles the mast above the spreaders was visibly crooked to the right side. On the advice of the mooring site employees I placed it on supports under the spreaders and after a few weeks it seemed somewhat straight again. When I reassembled it and put it onboard again, however, it seems that on right the side a sign of the blow can be seen.
After some investigation I discovered that those pieces of reinforcement on which rest the spreaders are not original but where installed after the mast has fallen down due to a shroud failure. It presented a minor dent and to reinforce the structure they dismounted the spreaders and built those supports that distribute the forces on a larger area.
What do you suggest to do?
The alternative I’m thinking are:
1. forget about it and go sailing, at least daysailing
2. get the mast down and sistering from inside
3. by a used mast (there’s one similar to mine who’s in good shape and ask only 1k€)

In you opinion my I go sailing with this small defect on the mast?
Here’re some mast photos:


John, After reading the quandary, what to do with a tired fiberglass boat, and being an owner of a 1974 boat I had to go deeper down the rabbit hole and read your Carbon Mast experience.

It is all so true. We get started on a path. Get various supporting contributions and when we start to have doubts about the chosen path we stop believing in our own abilities and defer to “experts”.

This happens in so many subtle ways that we can easily delude ourselves. Loose our way. I can only imagine the outcome if this would happen while at sea.

While reading your challenges and conclusions I was reminded of a Ted Talk I had watched. I share it for it’s intrinsic value.

Thank you for sharing what must have been a painful experience. Thank you for turning it into an educational message.