Carbon Fibre Spars in the 505 Class

DRAFT

No Trial of Carbon Fibre Spars

During the Open Forum portion of the annual meeting in 2000, in Durban RSA, some of the members present raised the issue of once again allowing carbon fibre spars. The IEC members present had also discussed this with our counterparts in the Flying Dutchman class, who are considering allowing carbon fibre spars.

At the open forum meeting the members of the IEC undertook to put together a carbon fibre spar trial, similar to what the IEC did to foster testing of the long luff spinnaker.

In subsequent discussion, the IEC concluded that the long luff spinnaker trial was not a great success as a trial, in that a very limited number of alternatives were evaluated, by a limited number of people. The cost of participating in the long luff spinnaker evaluation was the cost of modifying an existing spinnaker and hanging a block on an eye strap at a higher hoist position, whereas the cost of participating in the carbon fibre spar trial would be significantly higher � the cost of a one-off carbon fibre mast.

The IEC concluded that the greater cost of participating in carbon fibre spar trial, the availability of useful information on carbon fibre versus aluminium spars from other classes, the 505 class� own experience with carbon fibre masts in the late 1970s and early �80s and the relatively small performance improvement when compared to the difference the long luff spinnaker makes, meant that a carbon fibre spar trial would not be well supported, and would not provide us with much new information.

IEC members have researched carbon fibre masts by discussing carbon fibre 505 masts with a number of potential suppliers, touring the Selden Proctor facility, and discussing other class� experiences with carbon fibre spars, with key people in those classes. This paper summarizes our findings and presents the issues for consideration by the membership.

Philosophy of the Class Rules

The 505 Class Rules are one of the class� greatest strengths. The rules were written without constraining materials; they do not prevent the use of, or limit the use of new hull, spar and fitting technologies.
"9.1 Except where prescribed by these rules, either directly or by inference, there are no restrictions on the use of any materials in construction."
The 505 class rules have avoided including rules about things that don�t make much difference, and allow experimentation.

History

The 505 was created as a limited development, or conversely a less-than-strict-one-design, high performance racing dinghy, in 1955. For most of the years the 505 has been raced it was on the forefront of technical development. In addition to being one of the first dinghies to make effective use of the trapeze and to popularize it for other classes, the 505 was an early adopter of the spinnaker launcher, of non wooden spars, the first dinghy class which was much wider at the deck than at the waterline, an early adopter of polyester (Dacron) sails, then of Mylar, Kevlar and now 3DL sails. In hulls, the 505 was one of the first boats to be built in fiberglass, and was a leader in the adoption of cored construction, high performance fibers such as Kevlar and carbon fibre, and advanced resins such as epoxy and vinylester. 505 sailors have also been experimenting with foils for many years, developing gybing centerboards, while experiments with high aspect ratio foils go back at least to the mid seventies and probably earlier.

The 505 was also the class were some of the earliest experimentation with carbon fibre spars took place. 505 sailors were building composite aluminum/carbon fibre masts, carbon fibre and carbon fibre/Kevlar masts as early as the late seventies.

In 1979, several US East Coast 505 sailors worked with Ted Van Dusen who had an interesting weaving machine that could create a mast sized sock woven of carbon fibre and Kevlar, and built a mast on a male mandrel. This mast was known then � and even now, it is still around � as the snakeskin mast. Ethan Bixby and Larry Rosenfeld used this mast at the 1979 505 world championship in Durban South Africa, winning the pre-worlds (they had previous top finishes at worlds using typical aluminum masts). After the pre-worlds they decided the tip was too stiff, and using a jig saw cut sections out of the tip and then re-bonded the remaining portions of the mast together, with carbon fibre tape and epoxy.

Waterat Sailing Equipment built a female mold and built two carbon fiber masts for the 1981 505 World Championship in San Francisco Bay. Three more were built for the very windy 1982 505 World Championship in CORK Ireland. Two of the masts broke at the 1982 World Championship. Steve Benjamin had 3/32 rod shrouds, and the rod broke between the spreader and hounds. Jurgen Schonherr broke the ram tackle and the mast bent forward and broke. Both broke just after rounding the weather mark to the run with kite set, in a BIG � over 40 knot -- puff. All the D's in this group of 505s broke also. Cam Lewis (using a Waterat carbon fibre mast) was hooked in, sitting on the aft end of the tank with one hand under the gunwale as a running backstay, and getting lifted off the tank in the puffs. An interesting point about this event is that when competitors went to their backup aluminium spars, they were still winning races.

After the 1982 Worlds a number of 505 sailors were concerned that these carbon fibre masts cost considerably more than an aluminum spar, and believed that they gave a performance advantage. The class membership voted in a temporary ban on all carbon or carbon composite spars. At some later AGM this restriction was made a permanent rule in the class measurement rules.

Current Situation

Fast Forward to 2001. Appropriate aluminium alloys are rather more expensive than they were in the late �70s. Though still expensive, high modulus carbon fibre is now rather less expensive compared to aluminium alloys than it was in the late �70s. International 14s have been using carbon fibre spars for several years, as have the Finn and the Europe dinghy, and many racing yachts. A number of the Single Manufacturer One Designs (SMODs) have been introduced in the last five years with carbon fibre spars. The Flying Dutchman class is experimenting with carbon fibre spars. In the meantime, the 505 class has more or less standardized on only three sections, all aluminium alloy, and continues to ban carbon fibre spars. Many more sections than the D, M2 and Goldspar are used, but these three are used in rather greater numbers than other sections. The Proctor D and Superspar M2 are extruded only in England, while the Goldspar is made only in Australia.

Most 505 sailors have to import these sections from England or Australia, or buy from dealers who have imported the sections. Availability of these sections is limited in many countries where 505s are sailed, and particularly in the case of the Proctor D and Superspar M2, the cost of the spar is prohibitive in some of the countries were 505s are raced.

Frequently when high winds coincide with shallow-water venues, a number of masts are broken or damaged. Most of the time masts that have broken or that have dented walls cannot be effectively repaired. A number of 505 sailors report their Proctor D masts bending simply from heavy air racing; apparently the rig is only marginally capable of withstanding the loads applied to it.

The circumstances that existed when carbon fibre spars were temporarily banned, and when the ban was made permanent, have changed. The membership needs to re-evaluate its position on carbon fibre spars.

Issues

Cost

A common objection to carbon fibre spars is that they will be considerably more expensive than aluminum alloy spars. This may depend on what country the 505 sailor lives in. For example, in the USA, a fully rigged D, with standing and running rigging, spreaders and mast ram, vang/kicker attachment, gooseneck and spinnaker pole ring installed costs about US $1,500. A bare mast (gooseneck and spreader bracket installed) with the overlength rigging package can be purchased for approximately US $660 from a UK source, but the mast and rigging package have to be shipped to the US, shipping, handling and customs fees paid, and then the mast has to be rigged.

A fully rigged Proctor D ready to drop into one�s 505 and race with, costs approximately eight months salary for a Doctor in Zimbabwe.

Single carbon fibre masts will cost more than a Proctor D in the US, but not much more than the aluminum alloy mast. A fully rigged (as above) carbon fibre mast could probably be bought for 30% more than the aluminium alloy spar. Waterat Sailing Equipment would be a possible source. A number of other carbon fibre spar manufacturers, including Ted Van Dusen and Hall Spars could also supply carbon fibre spars to varying fitout levels.

The UK has several suppliers of carbon fibre spars as well, with perhaps Selden Proctor and Superspar being the two the 505 class is most familiar with.

While aluminium alloy spars are relatively easy to build once you have a nearby aluminium plant and extruder, they cannot be built without someone having incurred the huge capital cost for the plant and equipment. In contrast, carbon fibre spars could be built in your garage (no guarantees that you are successful the first time). Such a mast will almost certainly not be a better mast than a carbon spar produced on a high tech machine, but it might well be good enough. The cost of the materials, carbon fibre and epoxy, would drive the total cost of the mast, as the labour would be free. Especially if the carbon fibre and epoxy are subject to lower duty rates than a moulded carbon spar, this may be a very attractive option for 505 sailors outside of Europe, North America and perhaps Australia.

Various suggestions for rules that might limit the cost of carbon fibre masts have been suggested. However, we have no means to limit what someone can spend. Even a claiming rule would allow someone to spend what they wanted too, and risk losing the mast to a claimant afterwards. You cannot legislate cost. Furthermore, the potential for spending large amounts of money to develop faster rigs exists today, and no one has done so.

Obsoleting existing 505s

Allowing carbon fibre spars will not obsolete any 505 hulls. We risk obsolescing the current aluminium mast only. With two possible design exceptions, the IEC believes, after some research and analysis, that carbon fibre spars will not be so much faster than a Proctor D that they will instantly make the Proctor D rig obsolete. This view is supported by the carbon fibre spar vendors we have spoken to. Ian Howarth of Selden Proctor writes,

�In reality, the performance differences will not be huge unless sailing in waves (when the reduced pitching will become a major advantage with the carbon). I expect the majority of 'Club' 505 fleets who may not immediately change to carbon are sailed on flat water venues where the difference will not be too pronounced. Hence, based on the above view, the alloy spars will not immediately be obsolete.�

In support of this view consider what happened at the 1981 and 1982 world championships, the last time carbon fibre spars raced against aluminium spars in 505s. In 1981 the carbon fibre masts finished 1st and 6th. In 1982 a carbon fibre mast was first again. The mast builder � Larry Tuttle at Waterat � believes that the success of the rig was not due to the mast only, but to how well the mainsail worked with the mast. None-the-less, the carbon fibre spar equipped 505s did not demonstrate a noticeable speed advantage over those with aluminium spars, and sailors who switched back to aluminium spars during the 1982 world championship still won races.

While there have been developments in carbon fibre spars since that time, the developments offer more in terms of ease of building, and consistent masts, than they do in terms of a much faster carbon fibre mast.

There are two possible exceptions to the IEC�s belief that in reality carbon fibre spars will not be a large advantage over aluminium spars. They both result from the following class rule:

"7.2.1 The mast maybe stepped on the deck or into the hull. With the mast perpendicular to the base line, the after side at deck level shall not be less than 3048mm and not more than 3202mm forward of Station 11. The mast may be fixed or rotating. Excluding fittings, no dimension at right angles to the length may exceed l02mm."

Wing Mast

102mm (or ~ 4.016 inches) might be enough for someone to develop a narrow �wing mast� 505 spar that provided an aerodynamic advantage over current sections. The Europe Dinghy class had a similar rule to ours, and initially a number of competitors were developing � in some cases at high cost � wing masts. The Europe Dinghy class� solution was to tighten the circle rule so that it excluded the wing masts, but included conventionally sectioned carbon fibre spars, such as the standard Marstron spar that most Europe Dinghy sailors now use.

The 505 class may wish to consider reducing the 102mm dimension to something smaller, to forestall efforts to develop wing masts.

Rotating Mast

While we are unaware of any rotating rigs in 505s at the present time, the class rules explicitly allow them, and there were experiments with rotating rigs in the 1960s and �70s. Apparently these rigs were either two heavy, or too fragile, to demonstrate any advantage over the non-rotating rigs of the time.

It may well prove possible to develop a carbon fibre rotating mast that is both light enough and strong enough to be a viable rig, and this rotating rig could provide a noticeable speed advantage to a 505 using it.

The 505 class may wish to consider preventing the development and use of rotating masts, or preventing the development and use of carbon fibre rotating masts.

Availability

A concern exists over the availability of carbon fibre spars in all the countries where 505s are raced. As discussed above, the class currently uses primarily the Proctor D, the Superspar M2 and the Goldspar, each of which is made by only one supplier. Proctor and Superspar are in the UK, while Goldspar is in Australia. All 505 sailors not residing in the UK or Australia have to ship � or have shipped � spars to them.

There are a large number of carbon fibre spar manufacturers that may be interested in building masts for the 505 class, in more countries than just the UK and Australia, and as discussed above, carbon fibre spars could be home built, unlike aluminium spars.

Single Supplier

On carbon fibre mast alternative that was suggested to meet the goal of limiting mast cost, was to allow carbon fibre masts from only one supplier. These masts would not need to be identical, but would need to be similar. For example spreader bracket, jib halyard, spinnaker halyard, and shroud hounds would be fixed on all spars, but the bend characteristics could be altered on an individual mast to suit mainsail luff curve or crew weight.

If one manufacturer supplies all the carbon fibre masts it is likely that the costs can be limited, and might even end up slightly less than our current Proctor D rig.

However, 505 sailors around the world would still be importing masts from wherever this single manufacturer was, a situation even worse than we have today, and the masts would still be very expensive (just as current aluminium spars) in countries outside of Europe and North America, where 505s are raced.

Constraining the Spar

Round Mandrel and External Sail Track

It has been suggested that the cost of carbon fibre spars could be managed by requiring all carbon fibre masts to be built on a round mandrel � this results in a more or less round mast section � with an external sail track. This would resemble a carbon fibre version of the Goldspar or Z-spar masts.

A problem with this approach is that it limits which suppliers could build 505 masts. For example the Waterat mast mould built in 1981 builds a mast with a molded in sail track and the section is not round.

It also limits the class from taking full advantage of the technologies that are currently available as well as future developments. Selden Proctor�s equipment produces non-round section masts, and does not use a round mandrel, so their masts would not be legal either.

External Sail Track

A variation on the round mandrel suggestion was to allow non-round � for example oval section � mandrels, but still require external sail tracks. Again this approach would prevent some carbon fibre mast builders from competing for our business, and would also limit our ability to take advantage of what a new technology has to offer.

Transition Strategy

If the class membership wishes to once again allow carbon fibre spars, it may wish to consider a transition strategy that makes it easy for those sailors who wish to continue using their existing aluminium spars for some period of time. While carbon fibre offers several advantages over aluminium, some of these advantages affect longevity. However, many believe that the possible lighter weight and/or lower centre of gravity of a carbon fibre spar may be a significant advantage over the existing aluminium spars.

Minimum Weight and Centre of Gravity(CG)

As a transition strategy, the class may wish to put in a temporary rule requiring a minimum weight for carbon fibre spars, or possibly for all spars, and a centre of gravity rule to prevent a very light spar being brought up to weight with correctors at the heel, so as to keep the reduced moment of inertia advantage. Carbon fibre masts could be built to a lighter weight, and brought up to the minimum weight, and to the required CG, by adding correctors weights.

Carbon Fibre Booms and Spinnaker Poles

If the membership chooses to not yet allow carbon fibre masts, it may wish to allow the use of carbon fibre booms and spinnaker poles. These should provide minimal performance improvement over aluminium, but would allow those who would like to use them, to do so.

Single Supplier During Transition

As a transition strategy, the class may wish to restrict carbon fiber masts to a single supplier during the transition period. This assures a single manufacturer of enough demand, that they can properly do R&D and can price the spar more competitively with current aluminium spars. This restriction could be removed after the transition period to allow other suppliers, and home-builders, do have a go at building their own spars.