How to attach sail track to carbon mast?

Questions & Answers
1

MODERATOR’S NOTE: this is a Nonsuch forum. This post skirts the edges of Nonsuch topics. It is being allowed because (a) we Nonsuchers are by nature helpful; (b) the primary focus is carbon fiber masts and Tides sail track, both of which are of interest to Nonsuch sailors. Please keep it within bounds when replying.

Hi, I have a Wyliecat 30, not a Nonsuch, but the carbon mast is made by Ted Van Deusen, just like on carbon mast Nonsuches. It uses a Tides Marine sail track that is pulling out of the mast, and I am curious what attachment method Nonsuch owners recommend for attaching and installing a Tides track to the carbon mast so it doesn’t pull out?

Some people I know are making custom brackets from 7/8" stainless sail track and bolting every 2" to the mast with a nut on the back, but I am concerned about adding all of those holes to the mast weakening it, galvanic corrosion of the fasteners, and adding all of that weight aloft. The Wylie “factory” track was pop riveted directly to the mast without clips or brackets, but that doesn’t hold well enough, and is really hard to replace.

I hope it is okay to ask about a non-Nonsuch, we don’t have an online community for Wyliecat 30s as there were only about 20 made. I’m a big fan of Nonsuches and “modern catboats” in general.

2

Wylie cats are very nice boats… we had one at CPYC that did well in club races years ago.

Nonsuch boats with aluminum masts use 3 stainless bands with durable isolation material to isolate the aluminum from the stainless. ( HERE ) is a link to the replacement process I used on my Aluminum mast last spring. It may provide useful insights.

On Nonsuch boats the tracks fail at the bottom of the mast where most of the stress is. Pop-rivets may hold for the top 80% and only the lower section requires reinforcement ?

Tides Marine has been a reliable resource for Nonsuch boats, they may be helpful.

There are several Nonsuch owners with carbon masts that will likely chime in.

We have a Rendezvous in Greenport, NY next week with 30+ boats planning to attend. Might be a chance to see examples if you are near Greenport.

3

I had a Newick trimaran with a freestanding carbon mast. The sail track was a piece of pvc pipe with a slot cut out of the back side. The pipe was 1/2” id. This was bonded and taped to the mast tube, no fastners. I put a tides track on for the new sail that used slugs instead of a bolt rope. The entire set up was typical Newick, simple, elegant and effective.

4

Thank you for the info. I’m on the west coast (SF Bay). Catboats are not common over here, but they are very popular at my Yacht Club in particular (Richmond Yacht Club), we have I think 3 nonsuch 30s which are usually pretty rare on the west coast, and about half of the Wyliecats ever made just at our club. It’s decently windy here in the summer (30 knots is typical in afternoons) and everyone is now running big 650sqft square top laminated mainsails, so they tend to pull the tracks out of the mast.

MODERATOR’S NOTE: the last sentence of this post is getting closer to veering off Nonsuch topics. We ask everyone to stick to Nonsuch issues, as indicated at the top of the thread.

5

Hi,

You’ve got my sympathies on the carbon fiber mast problem. Nonsuches went out of production in the early-90’s after having switched to carbon fiber masts towards the end of the run. There are a few people who’ve gotten them recently. The Composite Engineering carbon fiber mast on mine was installed in 2003 after a previous owner damaged the original mast in a SF Bay racing accident.

I pulled loose the bottom 4-5 feet of the track and had to re-attach it, so I’m very familiar with your problem. You can find a discussion thread about my process here: Sail track on carbon fiber masts (or, "Well, damn...")

Short summary of my experience: I have an aluminum track and Ronstan racing sail slides. It is entirely epoxied to the mast with the exception of three machine screws tapped into mast at the bottom, middle and top. This works almost as well as Tides track. But, having had Tides on previous boats, if I didn’t have an adequate system and was choosing one, I’d prefer Tides.

Feel free to private message me and I’ll be happy to discuss it. I can also give you contact information for another Nonsuch sailor who had exactly your problem. Ted van Dusen is now 80 and was almost retired when I talked to him back when I had my problem, but the contact information I have for him may still work. He has handed over much of his business to a company called Moore Brothers. I can also help you get in touch with them.

-- Bob

6

Take a look also at: RE: unknown track for our NS260

This was the saga of a replacement pretty much identical to your problem.

-- Bob

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Thank you, I have reached out Ted Van Dusen, and the company responded saying this is a topic Ted will want to provide advice on, but he hasn’t done so yet. Good to know that Moore Brothers is now making the masts and may be worth talking to also. I do like the idea of a fully epoxy bonded track as that would avoid creating holes that can weaken the mast, but then I’d want a “lifetime” track of some kind. The Tides tracks only last about a decade apparently, so wouldn’t be ideal to epoxy directly to the mast.

It seems that Shaffer 7/8" stainless track is a good size that matches the Tides marine stainless clips, and can be used to create longer/stronger clips that can stay permanently on the mast. I wonder about the possibility of epoxying the stainless track directly to the mast, so that the Tides track can then run over it and be easily replaced in the future.

And I am very much happy to keep the topic to Tides tracks and Ted Van Dusen masts as used on Nonsuch boats, and will avoid discussing other boats as requested.

8

In my case, it was a 7/8" anodized aluminum track rather than the Schafer stainless (which is what I think was used on most of the boats). Ted recommended putting a layer of fiberglass between the carbon fiber and the mast track because of the possibility of galvanic interaction between metal and carbon fiber. Properly coated screws (e.g., lots of Tef-Gel) aren’t considered a big risk.

-- Bob

9

I don’t think direct surface galvanic corrosion should be an issue with the track, because there will be paint between the track and the mast. Plus, these seem to be filament wound masts with a thick layer of filler on the outside of the carbon to make it smooth, so the carbon itself should be pretty far from the surface. I am more concerned about the screws and nuts themselves, because I want to use backing nuts inside the mast, and loctite to keep them on, and I cannot think of a way to use both Tef-Gel and loctite on the same machine screw at the same time.

Two thoughts about this problem I was considering:

(1) I could be wrong, but I am not fully convinced that carbon fiber actually eats 316 stainless. I own another boat (Sage 17) that has a complete carbon deck, and all of the hardware is 316 stainless, and after 16 years of use in marine environments I rebed everything, and corrosion has not been an issue at all, even when there were leaks so the stainless/carbon interface was wet and salty. Perhaps this only applies to lower grades of stainless that are less corrosion resistant?

(2) I was thinking I could use small insulating sleeves for where each bolt passes through the mast, perhaps cut from a thin walled PTFE tubing. Maybe a plastic washer on the inside should be used also.

10

My ten cents.

I believe any hole in a carbon mast significantly reduces it’s stress factor.

11

I may have a useful data point for you, since my Nonsuch 36 has an aftermarket carbon mast built and supplied by Ted Van Dusen.

I have the original quote and invoice for the mast. It was supplied as a complete mast assembly, including the hardware and sail track, so this is not a later owner modification. The mast was supplied new in 2008 (and was probably manufactured in late 2007). The quote also specifies the mast’s Awlgrip finish.

The mast is fitted with an external Ronstan ball-bearing batten car system. The aluminum track itself is approximately 30 mm wide at the running surface, but has a much wider backing/base of approximately 60 mm, providing a substantial bonding area against the mast.

What may be particularly relevant to your project is that Van Dusen installed this track without a single mechanical fastener into the carbon mast. There are no screws or rivets through the track into the mast anywhere along its length.

The track is bonded onto the Awlgrip-finished mast with 3M 5200. Even the stopper at the bottom of the track is only screwed into the aluminum track itself; its screws do not penetrate the mast.

The system uses recirculating ball-bearing Ronstan cars. My mainsail is not fully battened; only the upper two battens are full-length. There are three types of cars on my installation: the large cars used for the head/gaff/halyard arrangement, approximately 110 mm long; regular intermediate cars, approximately 67 mm long; and batten cars, approximately 90 mm long.

As far as I have been able to determine, it is an older Ronstan/Frederiksen Series 30 system, although I have not yet positively identified the exact track part number. The track appears to have been designed with bonding in mind: approximately 30 mm wide at the running surface, approximately 60 mm wide at the bonding surface, and no mounting holes whatsoever.

The installation has now been in service for approximately 18 years.

So in this case we have a complete Van Dusen-built Nonsuch carbon mast where the mainsail loads are transferred to the mast through a bonded aluminum sail track, with zero mechanical fasteners penetrating the mast.

Of course, that does not automatically mean the same attachment method is suitable for a Tides track. Track geometry, bonding area, materials and load distribution all matter. But I thought this was a particularly relevant example for your project because this was the attachment method used by Van Dusen himself on a complete Nonsuch carbon mast.

I can take more detailed photographs or measurements of the track and its attachment if that would be useful.

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Mark H
N36#25
The Netherlands, Europe

12

Thank you everyone for the advice and info, it does seem like bonding to the mast is the proper way to fasten things, but these Ronstan aluminum track systems are very expensive, perhaps as much as $10k for cars and track suitable for a sail this large, so I’d like to find a way to reuse the Tides cars I already own. Bonding a stainless T-track to the mast to run a Tides track over may be the solution.

I have received two technically detailed e-mails from Dr. Ted Van Dusen, and will put the full text here in case the info is useful to others. Lots of his information is in fact Nonsuch specific, and lines up with the idea that bonding is the preferred method to attach things to the mast, but he mentions using a two part methacrilate adhesive:

Email 1:

I’m sorry to hear the fleet is having trouble with the masts that I designed and made for the the Wylie 30’s. Tom ordered the masts unfinished and I am not aware of the details on how they were outfitted. We have never used pop rivets on any mast that we have built, no matter the size. I am also not a fan of the tides track because the the length of the track for a WC 30 varies about 3" over the range of normal sailing temperatures and the mast hardly changes at all. I learned this when building our first Nonsuch 30 mast, using the tides track and the track buckled between the fasteners and wasn’t up to the loads of the Nonsuch with a considerably higher righting moment..

I was concerned that Tom might not be familiar with carbon masts and discussed the importance of proper installation of fittings on carbon masts. In order to reduce weight aloft and increase the righting moment, I tapered the diameter and wall thickness of the WC 30 mast so it had a nearly uniform stress when near the maximum righting moment. A few years later, I was asked about adding a spinnaker and I said that the spinnaker halyard had to be below 80% of the distance from the deck to the masthead and small enough so that it did not overpower the rig in windy conditions.

If you were to load up a well designed carbon mast until it broke and then repeated the test on an identical mast at a lower load for 10,000,000 cycles, you would find that it would find that it would fail between 60% and 80% of the load applied to the first test. If you did the same test with a aluminum or steel mast, they will break at 10% to 20% of the one load test. With a carbon mast about 60% the weight, no corrosion, and lasting several times longer, it seems like a dream come true. If you drill a small hole in in a round mast and put a compression load on it say from the halyard and rigging the stress on the sides of the hole will be three times the stress on the mast. If you enlarged the hole to 5% of the circumference, 95% of the mast would carry the load so the stress would increase only about 5% to about 3.16 the stress. Even a very small hole matters! Metals are ductlile and deform, reducing the stress near the hole. For the recreational sailor who avoids storms, aluminum masts last decades. Serious ocean racers tell me that they expect to replace their alunimun after 10 tears. When carbon reaches its strength limit it just breaks. Whenever we have to drill a hole in carbon, we gradually build up the thickness of the laminate near the hole, orienting the carbon to the load plus a safety factor so that the stress is well below the failure point. You can see a buildup in thickness around the chocker on the WC 30. We always recomend that the laminate be thickened where there is a hole. It is an extra task; however, it is well worth the effort in safety and longevity. Carbon also does not like abrupt changes in thickness. If you have any questions, please give us a call.

Regarding the screws in the holes in the mast, where the mast is in compression all the time, it is a lot better than nothing. Carbon is so rigid that any small gap between the screw and mast will allow movement which will increase the stress. Filling the gap with epoxy does not help much since the epoxy is much more flexible than the carbon and only 2% the strength. I recomend laying up a stack of carbon the thickness of the mast plus a little, cutting and sanding it to a slightly oversize tapered plug, fileing the holes in the mast to fit the plug, tapping the plugs in with epoxy, sanding the mast several inches above and below the holes down to the carbon, and laying up layers of carbon to a thickness of 1/3 the mast thickness, tapering down gradually in all directions. The mast has 75% of the fibers verticle, so if you can find both woven and unidirectional carbon fabric, it would make sense to alternate vertical uni and fabric layers. If you are having trouble finding a small quantity of the carbon, we can send you some.

Good luck,

Ted Van Dusen

Email two:

Near us us a Nonsuch 33 that has been doing a lot of off shore races incloding over a 10 Bermuda Races. He lost aluminum masts in the process due to fatigue cracking. He came to us for a Carbon Mast after seeing over 40 of our carbon masts racing in their annual regattas. We made him a carbon mast with a Harken anodized aluminum mast, because they are ovebuilt. Before the mast was painted we faired the mast and laid up a 3" wide strip of 8.5 oz fiberglass tape and epoxy where the track goes down to insulate the track from the carbon (about .9 V if it touches carbon and salt water). We sanded the glass with medium grit paper to get good adhesion and bondeded the track down (after washing the track with IPA, and lightily sanding with 320 grit, and used the strongest methacrilate adhesive we could find, Plexas MA320). The adhesive is squeezed out of a 2 part gun and has a 8 to 10 minute working until it starts to harden, so it is important to have everything marked out and 3 people to handle the track. We hold down the track with 1.5" wide masking tape at each end and then 6 to 8" apart while someone is sighting to see it is straight. It sounds scary, bud we never had any difficulty even outdoors in the sun and 80 degrees. You might want to consider this for your mast. You should be fine with the small line of holes covered by the glass and aluminum track reinforcing the area and save a lot of work. Once the track is down, all that you have to do is a little painting.

We used this system on the our around the world single handed masts and the tallest mast we made, 107 ft long on the Spirit of Bermuda and we just put one 20 foot track down after another and had everything done in an hour and a half with three people. This carbon mast was hit by lightening 4 months ago after 23 years service and shipped to us for untrasonic inspection. The lightening hit the top of the mast and vaporized the resin in a 3" diametern circle less than .1" deep, leaving undamaged carbon fiber and the same thing at the mast step. The ultra shoud found 9 very thin voids in a line between the top and bottom that were .5 to 1.2" long and .5" wide in the middle of the laminate. After some research, I decided that the way the carbon was woven together continuous from the top to the bottom it couldn’t go anywhere and it would do more damage to try to repair it. She sailed home in a windy Bermuda Race this year with no difficulty.

Ted

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It also sounds like one engineering consideration for Tides track is that is varies in length up to 3" or so with temperature changes and mast bending, so it must float free on the mast somehow. It seems like Nonsuch people tend to fix it at the bottom so it can run up a track and float at the top, and Wyliecat people seem to fix it at the top and let it float at the bottom, requiring taking the mast down or going aloft to replace the track. I probably will fix it at the top while the mast is down, to make sure that the sail is able to stay all the way up in the track when the mast bends. It seems a critical difference between my mast and the Nonsuch carbon masts is that mine is much more tapered and bendy to allow it to automatically depower in gusts, and this extreme bending requires some slightly different engineering considerations as it means the track is moving up and down the mast a lot more.

14

FWIW, Mark’s description of the sailtrack bonded directly to his N36 match is very similar to the track on my N26 carbon mast, although it sounds like his is 1 & 1/8th inches while mine is 7/8ths (which makes sense given the difference in sail loads between our models).

I believe the additional bonding surface of those tracks is likely to be very helpful.

Just thinking out loud, if using the 7/8" stainless track, it might be worthwhile to mechanically fasten it to some wider piece that would then be bonded to the mast.

My track is bonded with a two-part resin mix. Ted bought it from McMaster-Carr and then shipped it to me, so I don’t know the types. From Ted’s email that you reproduced, it sounds like it was done with the, “…strongest methacrilate adhesive we could find, Plexas MA320.”

I take comfort in Ted’s comment that:

I’m surprised by Ted’s comments about Tides track, which has worked quite well for probably hundreds of Nonsuches. I suspect that his opinion is colored partly by differences between carbon fiber vs. aluminum masts, as well as his lifetime focus on building masts for high performance and ocean racing boats that operate beyond the intended coastal cruising limits of Nonsuches.

-- Bob

15

Bob, if the adhesive came in a two column cartridge that auto-mixes the two parts as you dispense them, then it was probably an acrylic like Plexus, whereas if it was two separate containers you weigh out and then mix in a pot, it was probably an epoxy.

I’ve used “Weld Mount” brand two part structural acrylics to glue stainless studs to fiberglass for mounting hardware inside of boats without cutting holes, and found the stuff to be exceptionally strong.

Thank you again for your help, I am still learning and weighing options so haven’t decided on a plan yet, but I have already purchased 7/8" stainless track, but it looks like I could still return it if I find a better solution. It has a very narrow base, so like you said, it’s not very suitable for bonding. One idea would be to, instead of doubling the current number of holes, just keep them, but also bond to the surface.