The 29er Carbon Rig
This is the 5th or 6th carbon rig built for the 29er. The first one was 45mm OD (outside diameter) mast approx. 200mm longer than the existing rig.
The second one was a variation on the first, but an increase in OD to make it more “friendly”!
There are also 2-3 rigs in NZ but neither would appear to be acceptable.
This one (the photo above taken in Austria) was a complete re-design based on the previous information. OD is 55mm. It’s an Australian CST rig, it was taken to Medemblik last year to be shown at the worlds, and at this stage it had already been sailed in Australia for over a year.
It’s a 2-piece mast, the joint is about at the spreaders, it has carbon spreaders, rigging is near identical to a standard rig other than the hounds are approx. 100mm higher and it has a set of 6mm Dyneema D1’s. Spinnaker hoist is also about 100mm higher. (This is a function of D1’s.)
Why D1’s? It’s a function of the square head, if you are going to use a square head, then you need to control the lower mast to a greater extent than any amount of stiffening the lower mast can be given via laminate modification.
Why Dyneema D1’s? Because wire is pretty brutal! It’s also remarkably cost effective and we have purpose designed the gooseneck fitting to resolve all the loads. Adjustment is via a sliding splice!
Why a square head? Very probably 3 key reasons:
a) If you go to a Carbon rig, then the weight of the tubes drops to approximately ½ that of a comparable alloy rig. But given that the tubes are only approx. ½ the total weight, in that the wires and halyards are the other contributing factor, the total weight drops by 1/3 – 1/4. But the weight is lower! If you do nothing, then that reduction in weight will lead to a reduction in crew weight. There are a number of ways to counter this, one is to increase sail area, and you can do that by increasing hoist of the main, or by employing a square head.
b) Given that longevity of the rig is a key reason for the change, to achieve the sort of longevity that the 49er is currently enjoying, we exploit the “elastic yield” of both the mast and the sail cloth. So, what that means is we allow both the mast and sail to yield in a controlled and repeatable manner that does not exceed either’s elastic limit (once you exceed you do permanent damage). Presently the alloy rig exceeds its elastic limit every time you go sailing, same as an aeroplane, it’s only good for so many cycles. With the 49er, the mast would appear ageless, in that the likes of Outteridge and Burling were using 5 year old rigs in Rio.
c) There are considerable efficiencies from a square head if done correctly. There are also significant benefits WRT handling, that can be derived and this is bearing out in Austria presently. And I quote:
“What I can say in general is that it behaves a lot smoother than the old one especially in gusts and lulls…”
“The main is awesome… it feels really great and behaves really well”
“What I have to say is that the new one is quite a bit faster than the old one…as you can keep pressure longer in the sails (square top)”
All this is borne out via the data we are gathering also, it would appear that the new rig is much easier to sail (we also found this in the 49er) so it’s not faster, per say, but it just does not slow down, it’s far more forgiving, and that’s what we targeted.
A final point, when I originally designed the boat, I was pressed by the late Dave Ovington to go bigger and bigger in the jib. Probably went too far, so in part, the increase in mainsail area re-addresses this imbalance, and is one of the reasons the boat is now more balanced!
Where are we at now
Attached is one of the data files from Austria. Brown is Carbon, Blue is Std. Wind is from the top left.
The rig has been around now for 2 years, for the first 18 months that rig was used extensively in Australia, UK, Holland, Finland, France, Germany and though a condition of use was that we received feedback, not an iota was ever received.
Pretty disappointing actually given the money and resources that had been poured into it!
The rig is now in Austria, being sailed against a standard rig, with crews swapping and generally good investigative protocols being brought to bear, it will be the subject of a Thesis/Masters.
Upside is we are now getting weekly feedback, not just words but hard data that can be analysed and some serious decision making can happen.
All this ends July 12th when the rig will be taken to Lake Garda, probably sailed a few more times and then be put on the “Rack” at Arco under the watchful eye of Nautivela, and for anyone who wishes to charter a 29er with a carbon mast, have a go!
Where to next
I am waiting for all the information I can get out of Austria, so nothing is going to happen for a month.
Chris Turner of Ovington Boats has ordered a whole new rig, so this will be a new 3-piece mast, new mainsail, new jib and new spinnaker & a new boom fit-out!
3-piece mast is critical because of logistics, you can ship anything under 3m easily! Probably 50-55mm OD, we need to do the maths, integrated sleeves, etc etc.
New main is obvious, square head.
Jib, no real change, other than we will probably opt for a zipper luff.
Spinnaker, likely to be 100mm longer in the luff, and 50-70mm shorter in the foot to compensate so the area remains the same, but given that the new breed of crews are driving the boat harder and faster it’s only a matter of time before we start over running the spinnaker (same thing happened in the 49er). We could easily end up with a spinnaker ½ m² smaller and a tad flatter, shorter % luff.
We will also take the opportunity to up-date the fittings, the ram vang will still work the same, but with a 49er style Gooseneck, issues like falling off will be gone, it will be much simpler to rig, and much neater, same goes for a significant part of the fit-out, no function change, but fitting lay-out yes!
That rig will probably get to UK in the Autumn, and what happens with it then is up to Chris.
If and when it’s ever adopted by the class is up to the ICA, TMH & WS.
I have done my bit.
I have some other projects that need my attention!