Carbon Spars Opinions


From: Jesse Falsone
Sent: 19 May 2003 15:54
To: 505world
Subject: Carbon Spars Opinions

With the vote on carbon spars pending in the next few weeks, I thought I'd share two contrasting opinions on the issue with the 505 community. These opinions, as expressed by Howard Hamlin and Evert Myer, appeared in the latest issue of Tank Talk. Both Howie and Evert also expressed their thoughts at the 2002 AGM in Fremantle.

Regards,

Jesse Falsone

A Case for Carbon Masts
by Evert Myer

In discussions on the 505 World e-mail list and at the open forum during the Fremantle Worlds last year, many arguments favoring and opposing the use of carbon fiber composite materials in 505 spars were proffered. The mere fact that this proposal is once again a hotly debated issue in our class suggests that its relative merits and demerits need to be weighed.
Remember, we have been through all of this before. In the early eighties a couple of sailors started using carbon masts which lead to the adoption of a class rule that stipulated aluminum alloys and wood as the only permissible materials for use in masts, booms and spinnaker poles. The 505 is not a strict one-design class, rather a development class, and I believe that this rule runs against the grain and spirit of a boat that encourages innovation in other areas such as hull materials, foil design and rigging.
However, at the time it was probably a wise decision since carbon masts commanded a princely premium back 20 years ago that would have seriously inflated the costs of competitive 505 racing.

So, has anything changed over 20 years later? Has the price of carbon masts dropped sufficiently that it can be considered comparable to aluminum sections? Have construction techniques and material quality improved enough that carbon composite mast reliability and durability can now be considered equal, if not superior, to aluminum? Based on the facts and figures that I have seen these past 6 months (particularly the paper on carbon spars written by Carter Jackson of Australia), I have now believe that it is indeed possible to build a mast from carbon fiber that is cost effective, light, and durable.

These traits are very important to our fellow 505 sailors in countries with battered currencies like South Africa, Kenya and Zimbabwe. These guys simply can't afford to import sections from Proctor or Superspar. In fact, a young engineer or other professional in one of these countries would have to save two months salary to buy a Proctor 505 mast! Even the Aussies, who are still suffering the effects of the devaluing "Pacific Peso", seem to have a strong preference for carbon construction, which promotes home construction alternatives.

In addition, there is a strong argument from the UK, where 505 masts are cheapest, that a carbon mast would provide the 505 with more "sex appeal" as it goes head-to-head with the current crop of fad production skiffs.
Other advantages that have been better articulated by others include:

  • Better suitability to the Long Luff Spinnaker

  • Superior dynamic bend properties (i.e. potentially better gust response)

  • No permanent bend or creep issues

  • No fatigue life or corrosion performance decay

  • More resistant to dents, dings and side impacts

  • Easier to manage when rigging

  • Easier to repair when broken

  • A black carbon mast, boom and spinnaker pole looks way more cool that that metal tube

  • Able to withstand Simon Lake's weight hanging from the middle

So why is this still an issue? I believe that the primary reason boils down to the inequality that may arise during the transition period from aluminum to carbon. Wealthy sailors or those having access to mast and sail technology are envisioned to have a competitive edge. I am sure Howard has done a sterling job enumerating all the other down sides, so I would like to focus on how the class can mitigate these issues in a way that we are not faced with an initial arms race, while preserving the competitiveness and value of older "classic" 505's. In fact, if managed correctly, I believe that we can use this opportunity to level the playing field for less active, lower budget sailors.

First, let's all remember that it's "never" a good time to make such a switch. No matter how compelling the cost vs. performance benefit of carbon masts becomes, the switch is going to be painful for some if not for all of us to some degree. It is going to cost money. It might cause sail development to progress along a different path. These issues will never go away, and if continuous development is too much for the class to stomach, I would argue that we will still be using aluminum masts 20 years from now when obtaining one will be even more costly as production demand wanes. If this attitude had been prevalent throughout class history, maybe we would never have allowed aluminum masts, laminated sails, exotic hull construction, and high aspect foils.

So how do we mitigate the conversion process? I believe the following concepts, currently in the proposal adopted in Fremantle, would provide for a smoother transition to carbon spars:

  • Manage the initial conversion by stipulating a minimum weight and moment of inertia set at a comparable level to aluminum masts. This could be done using corrector weights, say up near the spreaders. A simple swing test could be set up to enforce this at major regattas. This measure effectively discourages (by negating benefits) of high modulus fibers and other expensive construction techniques.

  • Stipulate a maximum diameter and cord length, which would discourage wafer-thin, laminates (which increase cost) and wing masts.

Practically speaking, I am convinced that these measures would result in a mast that is only marginally more competitive than a good Proctor or SuperSpar section, although most serious sailors would probably still make the switch. Heck, some of us even have carbon fiber ram tubes, tillers, tiller extensions and transom flaps for all that's worth (it looks really cool on my yellow boat)! But I do not believe it will make a material difference once you get beyond the firsts 30 or 40 boats at the worlds. Most of us give up more on a single blown gibe or douse, and boat set-up and tuning is much more of a factor to those of us down the pack.
Anyway, I would argue that guys like Howard, who I understand has at one stage owned at least half a dozen aluminum masts of various weights and bend characteristics, will always have a leg up on the rest of us - carbon or not. Apparently, not all Proctor D's (or Cumulus, Stratos or Cumulus-Nimbus) are created equal, and top sailors have been known to hang on to sections from certain batches, since production variances can be quite large.

Rather, I offer that the following market consequences could have the opposite effect for sailors on a budget or those sailing older vintage 505's:

  • Availability of many good, second-hand masts. The difference between a good D or Cumulus and the old, heavy spar on a classic 505 is probably greater than the difference between a nice aluminum rig and a carbon rig with weight correctors. Also, I predict there will be some experimentation with carbon rigs amongst the leaders of the pack, so getting a good, slightly used mast that is good for the rest of us may be a distinct possibility. For example, as high-aspect boards become more in vogue, a perfectly good secondhand standard Waterat gibing centerboard can be had for a fraction of the original cost.

  • Availability of slightly used Technora, 3DL (or whatever) sails as the fanatics on both coasts keep getting new cuts from Jay Glaser or Ethan Bixby to suit their new masts. This is essentially the same mechanism as the one where top sailors get new boats every couple of years, thereby selling their old boats into a growing fleet of new 505 sailors and upcoming youngsters.

  • The ability to ultimately revive the competitiveness of an older, overweight boat. Lighter booms and spinnaker poles will save weight, and once we have all gone through the transition period, we can consider reducing the minimum mast weight by eliminating the corrector weights.
    Relatively speaking, this would benefit heavier boats more than lighter ones, since boats already at minimum weight would have to add corrector weights in the hull to compensate.

In conclusion, I believe that a change to carbon masts creates more of a competitive issue for those sailors in the rarified air near the top of the fleet, where a couple of boat lengths worth of speed is really important.
Top sailors also have the most invested in current mast development and tuning, and would have to start all over (isn't this part of the fun anyway?). For the rest of us, we will have the opportunity to access spars made from a material that makes much more sense in the long run. Sure, masts will still break if you lose a shroud or pile drive it into a shallow bottom, but I am sure that on average, masts will last much longer, won't degrade and won't bend. Additionally, carbon spars puts the 505 class into the 21'st century in terms of appeal and a modern look. To me, that is worth some continued development.

Switching to Carbon Masts Will Be a Mistake
by Howie Hamlin

The goals for any change in the class should be based on the following criteria: (1) will the change make the boat more fun to sail; (2) will the change increase long-term cost; and (3) will the change grow the class.
The recent switch to the long luff spinnaker met these criteria. Likewise, the switch from wood to aluminum spars decades ago also fit these criteria.
Aluminum extrusions cost less than wood, could be mass-produced, were more consistent in structural properties, were more durable, and collectively made the boat more fun which helped the class grow.

Below is a comprehensive list of why I think switching to carbon spars would be a mistake:

More Expensive - No one disputes that carbon masts are more expensive than aluminum. There are two reasons for this increased cost that should be considered. First, materials and production costs are higher compared to aluminum. Second, carbon requires more hand labor, which reduced consistency among spars. This necessitates the purchase of several spars to determine which is fastest. In this respect, switching to carbon spars would re-introduce many of wood's negative attributes. In fact, evolutionary changes brought about by manufacturing (changes to mandrels and molds) and materials developments will necessitate the purchase of even more spars. When the Finn class switched to carbon, profile changes (long and narrow) spurred further evolution just as one design was starting to take hold. Brian Ledbetter said he spent more on carbon masts in one campaign than he had spent on his previous four Olympic campaigns combined.

Not More Fun - Carbon masts will not make the 505 more fun to sail. When we switched to carbon masts in the 18' Skiff class, we were surprised to find that the boat was not more fun to sail, and I think the same will hold true in the 505.

Aluminum Masts Will Be Obsolete - Carbon masts will be marginally faster making all aluminum rigs obsolete.

Critical Bend Characteristics - 505 masts have only one set of shrouds 
(Ed: however 505 rules allow a mast to have any number of shrouds or spreaders). With much of the mast unsupported, bend characteristics are highly
critical in the 505. By comparison, 18's have 4 sets of shrouds, 14's and 49ers have 3 sets. Because skiff masts are so highly supported, the mast bend is not as critical. So, in skiffs the conversion from aluminum to carbon was much easier.

Consistency - Aluminum is mass-produced through dies that make each extrusion relatively consistent. Carbon masts can be made with infinite variability. Tooling shape and sizes can be changed easily. So can the type of carbon, weave, amount, placement, thickness, layers, direction, orientation, resin content, etc. That may be good for the few of us at the top of the class that have the time, money and testing team to try 4 or 5 masts to find the fastest one. If you spent all that time and money are you going to share that knowledge with the manufacturers and the rest of the world? Not likely.

Durability - Carbon mast design will evolve to a similar balance of durability and performance as we now have with aluminum. In others words, as we strive for the lightest mast possible, we will in time find the same acceptable failure rate in carbon as we now have with aluminum. Therefore, the expected increases in durability with carbon will not be realized.

Degrades in Sunlight - Carbon is susceptible to Ultra-Violet degradation, and requires a special UV coating and/or covers.

Repairs - When they break they tend to splinter over a long distance. Only round tubes can be repaired easily. I would be shocked if a round tube proves to be the fastest section. The carbon 18' skiff mast we broke was a molded teardrop section. The manufacturer, McConaghy, said it would cost more to repair than to make a new one.

Long Luff Spinnakers Don't Require Carbon Masts - I do not think the new spinnaker will be the major cause for mast failure. Most of the broken masts in Fremantle were caused by hitting the bottom. In skiffs, as in most boats, the solution for supporting big spinnakers is with more shrouds, not stiffer masts.

Suppliers - The current complaint is that most masts are purchased through two suppliers: Proctor and SuperSpars. The same will be true for carbon.
Once the carbon design settles down we will likely find that we all have to buy from the one supplier who makes the fastest carbon mast.

If It Ain't Broke, Then Don't Fix It - In 30 years I have broken only one 505 mast. Krister Bergstrom said he has never broken a mast.

Class Growth - Growth is a function of fun relative to cost. Carbon will make the boat more costly without increasing the fun, so it will reduce growth.

From: Simon J Lake
Sent: 24 June 2003 23:37
To: 505world-list
Subject: Re: Carbon Spars Ballot

Dear All,

There were a couple of articles, one for introducing, and one against introducing carbon spars on pages 30 & 30 of the spring 2003 edition of US Associations Tank Talk magazine. They are well worth a read before casting your vote in the ballot. 

Tank Talk can be downloaded as a pdf file from
https://www.int505.org/usa/usclass/tanktalk/index.htm  (Ed. or see above)

One other factor to bear in mind is that late last year one of the three UK aluminum mast manufacturers producing masts for the 505 (probably number 2 in UK sales to the 505 fleet) ceased production of aluminum spars to concentrate on carbon spars production. This could be the begining of a trend.

Regards,

Simon J Lake
GBR8835? - hopefully sometime very soon.

From: Carter Jackson 
Sent: 26 June 2003 02:10
To: 'Bill Green'; 505world-list; 505usa
Subject: RE: Carbon Rig Experience

As many of you know I in conjunction with Composite Spars and Tube developed the most recent Carbon 505 spar. It is a filament wound mast that was developed from the current Proctor D and Cumulus Sections with considerations of the new loads our masts now have with the Long Luff  Kite.

The development was done on and off the water, bend testing several sections and sailing with the rig. We were able to reproduce the fore and aft bend easily with the very first prototype. This is one  of the key advantages with Carbon, contrary to popular belief, you can replicate easily and design rigs with crew weight in mind. It was interesting to note that of all the Aluminium sections we bend tested there were no 2 the same, and they did not correspond to their spec sheets.

In summary compared to the Proctor D (because this is the most commonly known) the first CST tube was very similar fore and aft although a little stiffer in the base and softer in the tip, probably a better mast than what we all use now, (see fig 1), the rig was significantly stiffer sideways (29%), this was designed this way to take into account the extra loads of the LLS.
This rig was also built for durability, Hence the over-engineering, however we could easily make this the same as what we use now.

It is important to note that this rig was the first prototype and was tuned to get the fore and aft stiffness correct, as stated above over-engineering the side bend was an experiment for the extra loads of the LLS. Our belief also is that this will make a better rig going down this path anyhow, the first one was definitely overkill, in saying that though we were definitely not slow.

I fitted the rig myself, exactly the same way I would have fitted an Aluminium mast. This was made easy as we could spin the build-ups into the mast lay up. Otherwise you cut the exits the same way and file them out. You just need to be careful using any Aluminium fittings as they will react with the Carbon. Placing Plastic or Glue under Aluminium fitting easily combats this.

The rig was finished at the end of the Fremantle World's and has been sailed with ever since. The Rig has been out in 30 knots a couple of times and consistently sailed in breezes over 20 knots. It did not flinch, especially down wind with the Kite on, it was a relief to look up and see the rig only slightly laying off.

It has been fun developing the rig also. As the 505 are not a strict one-design class, rather a development class, I believe this is why many of us sail this class. We have seen much development and innovation in other areas such as hull materials, foil design and rigging over the years. Once upon a time we did allow Carbon rigs and I believe the current rule runs against the Spirit of a semi-development class. We should be encouraging people to keep thinking of new ideas, as development breed's interest, which is important to the health of the class.

We have sailed in many club races against boats we new well and had a fair idea of their pace. 
Down range we may have been slightly quicker, up range our pace was good though we still need to do some tuning. Our feeling is we were faster down wind, although there are many variables and lots of different ideas with Kites at the moment.

We have worked out some good ideas for carrying the correctors that would be mandatory for a few years, easily removable and not bulky on the outside of the mast.
The only custom fitting we had to make was a heel plug, these would be easily made in production to suit the section. Otherwise all fittings were standard and could be retrofitted from Aluminium masts.

Again I would like to thank Clive Watts from Composite Spars and Tube for the time and effort he has put into the development of the 505 Carbon mast. We are at a point in the development curve because of his efforts that would allow people to order masts which are on the pace immediately if the decision is to go Carbon.

This is only the text to a document I will post on the World site with photos and Graphs of how we did the bend testing. I was on the Carbon committee and decided to do this so that people could have a hopefully informed opinion, and not the usual of nobody doing anything about it. All prices and other findings
are on the CST web site, also happy to field any other questions. Hope this helps a little in your decision.

regards
Carter

From: Clive Watts 
Sent: 26 June 2003 09:13
To: Carter Jackson; 'Bill Green'; 505world-list; 505usa
Subject: RE: Carbon Rig Experience

We have posted some of the photos and bend curves of the CST1 carbon 505 mast on our web page.

See http://www.compositespars.com/505_carbon_spar.htm 

Rgds

Clive Watts
Managing Director
Composite Spars & Tube
P: +61 2 9668 8488
F: +61 2 9668 8499
POB 651, Caringbah, NSW, 1495, Australia
78-80 Tasman Street, Kurnell, NSW, 2231, Australia
www.compositespars.com