Any direct link to "locked in" rules?

To the best of my knowledge

F12 Rules

While I personally don't disagree with those class rule (my design adheres to them) I don't think these were generally accepted by all.

Wouter

Nothing has been generally accepted by all, but these rules are as discussed in a previous thread and I believe define a group of variables that include all the proposed designs. At least all the ones that have been brought into the open. How do we go about formalising these or some alternate rules? Do all the current owner's get a vote? ie. gato only? Do all the owners and people currently building get a vote? Or do we as a group of interested and "like minded" people endeavour to come to a sensible consensus?

We all did agree on 3.80 mtr as maximum overall length for the F12. Of that I'm sure. At least we had I "I agree, lets do that" from all 4 persons must involved with the F12. Retired_Geek, Scarecrow, Phill and myself.

All the rest failed to achieve concensus among even this small group.

I'm still of the opinion that we need a tighter ruleset then that to make this class work and be a succes.




I think announcement, discussion and (majority) acceptance ON THIS FORUM to be the only way forward at this time.

Currently the group is still small enough to reach a concensus, with passing time the group will grow and make it much harder to get agreement. So I think the basic foundation needs to be lay down as soon as we can. At this time I would include everybody who is (seriously) interested in the discussions and the agreement. Of course some people (builders, designers) will always be a little more important then a "passer-by", but that should really not be a problem apart from some huffing and puffing.

The main point is that we set ourselves a goal of reaching a final agreement by a set time. If we need more time to gain experience then also set a date a year in the future for a large scale final review after which the setup and class are finalized and kept constant over time.

It would be nice to have a more formal review of the boat by gato at this time. Like is 7.0 sq. mtr a good size sail ? How heavy is the boat now and what is the lowest we can achieve with rotomolded hulls.

I'm a little involved in polyethyleen kayaks and these weight about 22 kg for 3.55 mtr length. The volume is not unlike a small cat hull and so it appears that 25 kg per F12 hull in well redevelopped PE (poly-ethyleen) is possible. Pretty much putting the ready to sail F12 at about 70 kg. PE is pretty far developped now in commerical kayaks, these guys have been at it for years now trying to get these as light as possible. PE is VERY abuse resistant.

I'm convinced that the rotomolded PE production of F12's is a huge commericial benefit. Think rentals and cheap production. Typical kayaks go for 600 Euro. Making sub 1500 Euro's for 2 F12 hulls viable. This will still allow the F12 to be commercially available for our targetted low costs.

I think this should be considered when setting a minimal F12 weight. I'm sure a few kg difference is acceptable enough, but not 20 kg (50 kg ply versus 70 kg PE)

Wouter

Gato came in around 50kg if you put the minimum weight at 70kg (the same weight as an 18ft cat) you will kill the class. Both of my kids cats will be piggybacked on my cat so we can all travel and sail. Minimum weight should be whatever the current lightest F12 is. The rules should be set in concrete ASAP.
regards

No we won't kill the class if we set its weight higher then the absolutely minimum that is technical possible. You can build an A-cat for just under 50 kg and still the class is very succesful at 75 kg. Additionally, this is the only 18 ft cat that I know off that even comes close to your quoted 70 kg. But for that feat it is also the most expensive 18 foot catamaran and won't survive any dock ramming.

Remember, whatever we decide for minimum weight now will have a big impact on the F12 future. Set it too low and it will be economically unviable, set it to high and it will be insufficiently attractive. I personally still believe 60 kg min weight as proposed last year and taken up in the provisional class rules is the best compromise.

And I wish to underline again that the only way to make these boats in series for our stated low asking price is by rotomolding. Timber is too prohibitive labour intensive and foam/glass is relatively expensive again because it is labour intensive.

So the question become whether we want a home-builder class or a large class with commercial builders and retailers. If we want to F12 to be trainer for kids and teenagers then we HAVE to build a large class internationally and we simply can do that by homebuilding alone.

Wouter

But if Gato can build a ply (note he used 4mm not the recommended 3mm) boat under the "minimum" weight then we are by no means setting the weight at the lightest possible, instead I'd say its pretty realistic. A composite boat will be lighter again. No body will invest in rotomolding tooling until the class is established (it make composite tooling look cheap). So Roto moulding will not be the thing that gets the class off the ground.

25 kg per hull. <img src="http://www.catsailor.com/forums/images/graemlins/shocked.gif" alt="" />

My F16 hulls are lighter than that. I admit they have some pretty fancy work in them but surely and F12 can be lighter than that. The Arafura Cadet have a minimum platform weight of 36kg and that design is 45 years old.

Who is going to carry this 70 kg beast? I still remember how heavy my near minimum weight AC was.

http://www.arrowarafura.com

Gato,

What was the ready to sail weight of your DS hull and was it made entirely of out 4 mm ply ?

Such data would really help in discussion the possible minimum weight ruling for F12.

With respect to rotomolded production. Indeed this will not start the class, but it will be a huge benefit in growing it at a later time. Even, our competition, the dinghies are increasingly going for rotomoulded production and we must not let them get an advantage over us. Same with Kayaks, We have got to set ourselves up to compete effectively with these.

Again, I'm not very concerned about the roto stuff being a little heavier then the optimized F12, but not by alot. I think a 60 kg = min with roto at 70 kg could be a very attractive setup.

Wouter

Why do new cat classes generally have fully rigged minimum weights? Why not platform weights (hulls, beams, tramps). Most dinghy classes only have hull weights.

Positives for platform only minimum weights:
- From a designers point of view it is much easier to perform an accurate weight estimate with fewer items.
- Easier to measure at regattas.
- Better promotional aspect because the advertising has the lighter weight stated.

If the F12 is to be car topable then this is the weight ppl are interested in.

Thanks for the link. I'm gonna with with that for the moment.

ncik,

I like full weight as this is what you need to design to anyway. Also it gives a better equality between boats for example if we set a platform weight of say 36kg (as per the Arafura) then two boats turned up one with and one without a carbon mast then there would be a big difference in final weights. Having a total weight means we don't have to over complicate the rules and limit choices.

I can't wait to see what you come up with. Let me know if I can help.

How is a kid going to get 70kg on top of mums car, launch and retrieve it themselves. Professional builders could turn out foam F12's in no time with a jig. My boats will never be 70kg and you can't grandfather out the first boats that launch the class, we don't even know what RG and Phil will come up with yet. Whatever these boats come in at is the class standard for me.

Totally agree Jeff.

While I am a little ways off building one of these yet (kids are 2 and 6 months). I can certainly see one sitting on top of the blade in a few years time. I think a 70kg F12 will struggle against the 50kg arafura's in australia too.

The reason I am so interested in the project is because it is what I wanted when I was sailing the AC. Modern hull shape (back then it was the A Class/Taipan/Nacra/AO), high aspect mainsail, daggerboards, two on trapeze. I designed lots of these as a kid and even made a model one. My design also had an asymmetric spinnaker which I copied from the 18 foot skiffs. Everybody laughed at me at the thought of a spinnaker on catamaran.

My prefered solution to the whole rules thing is to confirm the box as described in the above attachment (see poll threads) and then when a certain number of boats have been launched hand the whole thing over to the people who own the boats to discuss and vote on finalising the rules. In the weight thread I suggested that this should be set at 10 boats. Together the owners of these boats will have spent approx $20-30k and they deserve the right to shape the class's future a lot more than a group of people chatting on a sailing forum.

None of the boats currently being built are carbon rule beaters they are all being home built with "reasonable" levels of technology as is my understanding of the original concept of the class and none of these people are going to vote in a minimum weight so low that it makes their boats worthless.

Maybe an alternative to waiting until a certain number of boats are built is to wait for a certain number of designs to be built (3 or 4) as this will then give a good sample size upon which to base decisions.

My boat ended up at 52 kgs, and I did not hunt weight and it's 4mm all over. Think you could get down to 40 kg if really trying.
Rather 50 kg than 70 kg, 20 kg is a lot to carry around.
I have had some more kids sailing the boat and the rest seems all right.

Personally I'm quite happy to stay at 60 kg (as we are now), halveways so to say.



My design is still using alu beams and alu mast. It can use carbon tubing but a new standard alu alloy is taking over the market that is just strong enough for usage in beams and masts.

Its 6060-T6 / AlMgSi 0.5 F22 with a garanteed minimum elasticity boundery (0.2%) value of 160 MPa.

It is cheap, very corrosion resistant, sufficiently hard and quickly becoming THE standard alloy that even local common household hardware stores are stocking (even when they don't know it). The 0.2% boundery is just enough to use it for a unstayed mast, but the final test this winter will tell.

Currently, I'm testing axles made from this variety and they are holding up extremely well. That is they have hold up under a 120 kg pilot getting himself airborn and landing on a hardsurface; among other things..

I have just purchased 18 mtr tubing of 6060-T6 for 140 Euro's. That, I call cheap. I've also bought two unstayed alu masts of 5.5 mtr length ready to take a sleeved sail for a total cost of 250 Euro's = 125 Euro's per mast. The sleeved sail for it (currently 5.5 sq. mtr. area for the initial test) was 400 Euro's. Basically, (collapsable) mast, sail+battens, and boom+ fork was a total of 750 Euro's INCLUDING shipping.

Indeed, I have no money to play with at this time, but somebody is giving me a small sponsorship for landyachting. I'm using this to also do some testing on the setup I'm planning for the F12.

Anyway, I'm quite happy to start off the minimum ready to sail 60 kg (possibly with corrector weights) and when a 4 mm ply + all alu boat can be build at 50 kg then we can always lower this value.

I have never campaigned for a 70 kg minimum weight, that is just assumed by others who don't read the posts very closely. I have campaigned for not getting to far away from what can be had by rotomoulding and for not setting the limit at what is technically possible but economically unviable.

Wouter

Scarecrow,

How much volume is enclosed in your hulls ?


Wouter

The papertiger class 4.267m built in ply has a class weight of 50kg i have built one of these in ply at 43kg (low tec) we are building the RGcats in NZ (mid tec)these have to be easy to transport ,rig,launch,sail,have fun, for the kids any heavy dog!!!! will not get the right message across sailing is fun and easy. i want my son to be able to get the reward of preparing and launching the boat himself.not having to rely on somone else.my opinion for what it is whorth 45kg min it wont stop heavyer being compeditive. by the way will be building a ply vershion on the gig to compare
bill

Hi Billby,

are you suggesting 45kg all up or platform only?