March 4, 2009
Many thanks for your letter further defining the issues involved in the ongoing dialogue regarding carbon fiber spars. We are gratified to see that the exchange is moving us all toward a better understanding of what the various implications of our intent to convert might be. Also, we would hope, a better understanding all around of exactly what it is that we have been developing. The NEH fleet is very appreciative indeed of the WCA’s willingness to devote time and effort to this important issue.
Perhaps I should start by addressing the technical aspects of the subject, and leave the issues concerning class approval for later.
I well recall Herb’s presentation at the 2006 Bermuda Race Week, as I recall the various discussions held at the Nantucket Worlds in 2007. There was, at the time, some concern about future availability of alloy spars, the cost of carbon fiber (c/f) spars, and the possible rig configurations. The suggestion was advanced at Nantucket that we explore the possibility of developing a c/f rig that would accommodate both configurations currently in use. There was also, as I remember, the suggestion that such a rig should be ballasted to perform similarly to the existing alloy rigs.
Please allow me to review some of these issues: First of all, in NEH our interest in c/f spars did not result from a concern about the availability of alloy spars. When several members of our fleet expressed a desire to convert to strictly one-design rigs, the class repeatedly voted against aluminum, but declared itself open to the idea of carbon fiber. While this may have been partially for intangible (emotional) reasons, there was also a clear sense that if we were to change, we should not take a half step backwards and adopt fifty year old aluminum technology, but move forward and adopt the technology and material that almost certainly everyone would be using in future years. Over the course of three years, alloy spars were voted down three times, while our Technical Committee was asked to explore the possibility, and implications, of a conversion to c/f. After all, with the exception of Nantucket’s new fleet, we would be the only fleet to consider changing spar material within the last 25 years or so, probably longer. While alloy spars were the obvious – the only! – choice when Marblehead and Long island et al. changed over, this is no longer the case.
Second, insofar as we have a large number of older wooden boats, we realized that a lighter, stiffer mast would be of considerable help in prolonging their life span. This factor, combined with the advantageous minimal maintenance costs, encouraged us in considering the acknowledged additional initial cost of c/f as an expense that would be worth incurring. The combination of all these factors convinced us that if we were to make the change, we should unhesitatingly adopt carbon fiber rigs.
The other most significant technical issue in adopting c/f spars is, as we all well know, what configuration the rig should assume.
The premises that everyone in NEH agrees to are two: first, we want to continue sailing with the ¾ profile, for traditional and aesthetic reasons, and also because we all feel that the boats sail perfectly as they are, and can see no reason to change to a rig profile for which they were not designed. Second, we have decided that while we are at it, we should restore the “missing 8 inches” to the height of the rig, and bring it into concordance with all the other fleets, which use class specifications for mast length.
As for the actual rig configuration (one or two spreaders, jumpers, etc.) we have decided to adopt a somewhat Wrightish (or was it Gropius?) approach and let form follow function. We eventually winnowed the potential spar makers down to two contenders, Southern Spars and Hall Spars, presented them with the parameters we desired, and suggested that they in turn offer the design solution that they felt would best answer our needs. After all, we may be a Technical Committee, but we’re not engineers …
Both contenders unhesitatingly recommended a single spreader rig, for the self evident reason that the material offers ample strength, making a double spreader/jumper rig unnecessary. Interestingly, Southern Spars suggested we adopt wide-angle jumpers (angled 20º forward from an athwartships line) with the single spreader rig. This was not in order to control fore and aft mast bend, which in c/f masts is determined by the laminate schedule, but lateral bend, as they felt that leaving the top ¼ of the mast unsupported would make that harder to control. Their alternative would have been a heavier layup. As I’ve explained before, Hall Spars took a different approach, and suggested that we simply move the upper shroud attachment point up, thus offering greater lateral support near the top of the mast. I believe we have sent you diagrams illustrating the intended rig.
When our fleet chose Hall Spars as the designated spar maker, we examined their proposal even more closely, and with their engineers realized that their solution also meant that the single-spreader mast they were considering could easily be configured to either our desired ¾ profile, or to the 7/8 profile used by several other fleets.
Please let us emphasize here – in confirmation of your query – that when we say that our proposed mast can work in both these profiles it does not mean that the mast can also be made in a two-spreader configuration. As any spar maker will tell you, to build a mast that can be fitted with either a single-spreader or a double-spreader rig is impractical and expensive, and in any case they will very strongly urge you to abandon such an idea. All we are suggesting is that by eliminating double spreaders and jumpers the forestay attachment point can very easily be changed to satisfy either preference without changing the spreader and shroud configuration. It is the very simplicity of our proposed design that gives the spar maker that option. The addition of jumpers complicates that flexibility and adds further expense to its possible implementation.
An additional notion that we consider unnecessary is that of adding corrector weights to whatever mast we might end up with. Obviously such a move is unwarranted within a fleet. The idea that, no matter what the mast configuration is, a c/f spar can be made to behave like an alloy spar is tenuous at best. Even if the weight were to be corrected tolerably closely, the bend characteristics would be different. In any case, we fail to see the point of such a move.
We have thought about the issue of mainsail shape and longevity as well. It’s important to remember that we have the shortest racing season of any fleet (except perhaps Chester) and thus our sails tend to have a relatively long competitive life span. Carbon fiber as a material and as we are engineering it will give us a mast that is inherently stiffer than either an aluminum or wooden spar, although some bend will be available by backstay tension, which will to a degree help keep sails competitive. In addition, please keep in mind that our fleet does not use Dacron sails, rather a mylar laminate which has proven to have remarkable shape retention qualities over time (and which, incidentally, was an innovative step that at the time created considerable dialogue within the class and with the WCA …!) At present we fully expect our mainsails to remain competitive for at least five years, if the jibs we have been using for the past three seasons are any indication of how well our sail cloth works.
A couple of additional points, if we may: as we interpret the current WCA position, even if we were to consider the adoption of jumpers on a single spreader rig, we would not be allowed to do so and retain the ¾ rig profile, which, we need not remind anyone, is the original and traditional profile for which the boats were designed. We would be obliged to adopt a 7/8 profile, which we very much don’t like and don’t want. A single spreader ¾ profile – with or without jumpers – would still, by the WCA’s definition, be considered a third rig configuration, and thus would pose the exact same problem(s). We fully understand and appreciate the WCA’s perspective on this issue, but would like to again point out that it is a position which seems predicated on the use of alloy spars; or, if you will, a position predicated on the status quo. Our belief is that, if we are to proceed with our step forward, the status quo becomes to some degree irrelevant, and a fresh approach must be thought through.
We understand that the WCA is in the process of “getting the house in order,” as you put it, and a good move it is too. It’s apparent that the NEH fleet is now part of the house cleaning, in one way or another, which is why we have been consistently asking the WCA for guidance in helping us move ahead, and providing them with updates of where our research and development process has been leading us.
Please be assured that we have no argument with the WCA’s viewpoint regarding fleet approval and recognition. Our concern is that our intent to eventually improve our sailing by the adoption of carbon fiber spars not be rendered ineffective by the imposition of restrictions that might, in the end, make the entire effort superfluous. One of our original suggestions to the WCA on this subject has been that it adopt a forward-looking stance on this issue, with a view to the eventual standardization of all the fleets. We have asked that it work with us on rig development and create a standard that recognizes and takes advantage of the inherent characteristics of c/f, and which would become the one specification to be used by all fleets in the future when, as they are bound to do eventually, they replace their rigs. This is, admittedly, a long-term view, but we are presented with the problem now, or in the near future, and so we now have every opportunity to work toward that end.
As a concluding point, we would like to reiterate that what we are doing at present is building a set of prototype spars for evaluation, designed in accordance with the best engineering practice available from a highly reputable spar maker. We are not contemplating a fleet conversion in the immediate future; given the current financial climate, an eventual final decision may be even further away than initially thought. It would seem logical that the WCA, indeed any concerned IOD sailor anywhere, avail themselves of our invitation to visit us and sail the new rig next summer, and thus create a well-informed environment for further future discussion.
On behalf of the NEH Technical Committee, I would once again like to thank you and the WCA Executive Committee for continuing to explore with us the various possible solutions to our intended evolution.