Hi Everybody,

As many catsailors, I am primarily interested in high performance boats, I have been sailing A-Cat for 15 years, still involved in, but more as potential home design, home made boat.
Investigating A Cat project I realized that B-Cat is probably the best trade-off for many reasons, as long as you can find crew easily.

A-Cat main issues issues are:
1-Storage of the boat
Usually, at least in France, your A-Cat is not welcomed on a traditional Cat parking because each time you have a tempest, the old laser or Hobie 14 recklessly hooked on the ground, flies across the parking and usually land on your carbon toy. As a result to avoid insurance problems, most of sailing club avoid ACat or is is at your own risk.
So if you don't have a garden/parking to keep your boat safe on the trailor at home, you sail winsurf or F18.

2- Relative cost of carbon laminate (DIY perspective)
For a Acat you will buy 220g/ square meter laminate, which is only 30% cheaper than 440g you will use for B-Cat hulls.
and it is nearly the same amout of work.
As a benchmark just compare the M 20 price with the new Marström A Cat price.
Everything else equal, the 500g laminate used for the M20 is probably more forgiving than the 300g used for the A-cat,
and will probably last longer, which makes the M20 even cheaper if in addition, you consider both boat life's expectancy.
As a result a M 20 using foam instead of honeycomb would be perfect and probably cheaper.

Remarks about width, weight and sail area are very interesting, and to be consistent with the "aging sailor's population" argument, I woul notice that A -Cat is easy compared to F18 which is easier than Tornado.
Physical requirements for heavy , overwidth, combined with hudge sail area is out of reach for most of the over 45 sailors but former Tornado champions.
I would love to have a 140 kg F20 I could sail with a 55 kg girl friend so with a 145 kg crew fully dressed.
I would prefer a single mainsail without jib for simplicity weigh, cost and aerodynamic efficiency.
No jib means much less stress on the fore parts of the hulls, as you don't need to maintain hudge tension on your jib's leading edge, and overall lead to a lighter boat.
According to my experience with A-Cat the higher centre of sail area for uni-rig is not an issue as long as you have less parasit & induced drag and as long as the top of the sail can be twisted enough with downhaul, pre-bend and ....
Lighter boat means less sail area and less stress on the crew, especially for the spinnaker's slave.

3- The F20 Class issue.
Reference to a customized B- Class rule is probably the solutions.
In order to adress the crew weight issue, we could consider sail area combined with max weight corrector (5kg).
Lighter crew will have a smaller mainsail with lower sail center, higher aspect ration lower induced drag winward and lower max lift downwind.
According to the number of rocket scientists, engineers and PhD on sailing forums I feel confident that this issue will find a smart solution.
In addition, sailing area adjustment could be applied for old Nacra 20 or Tornado, in order to start a fleet with all existing 20.
If the 20 Class favors a not too exclusive boat concept, affordable on a $$ perspective, and not exhausting for the crew, especially if DIY solutions are developped, it could take off.
Easy to fold and unfold the boat is also part of the cost, as for ACat, overall cost is also related to storage issue, at least for some of the potential owners, and a 2 parts mast will be optimum.

If Class development is not supported by a boat factory, it could be by carbon fiber manufacterers, and by the Class Association which has a good bargaining power compared to lonely home builders.
Nothing precludes the Class Association to rise fees in order to develop a mast mould with a mast builders, and keep costs as low as possible.Todays a new Nacra F18 alloy mast is not really cheaper than a Marstrôm Tornado carbon mast??? market driving force probably?? marketing ??
The same for the crossbeam, in addition with a fixed width it is possible to create pierce-wave beams (see link:http://18ht.free.fr/Avancement/V016/Calculs/Images/ImgRDMPoutre.gif) which allow less free-board for the hulls and
hence less weight. The link does not provide a true picture of the crossbeam. It is a 100 mm circle under the mast and it moves gradually to a flat ellipse at the gunwhale, does not require dolphin-striker, and are plug in the hulls with some "conical" adjustment, so no metal, no bolt no screw, and easy to fold and unfold especially without jib.

Carbon mast and crossbeam would be available for home-build projects as long as they pay association's fees.

Look forward reading your comments, in the meantime I have to go back to my A Cat problems.

Cheers everybody

EK