I've just got of the phone with another "potential" customer who was asking about different sail plans etc for kids of different ages and experiances this is what we came up with.

Again this is to suit his requirements, not necessarily what I would recommend.

Ok i have searched the house and come up with the photos of the cat jeffs seen at my house. It's called a micro cat it's 8 feet long fiberglass uni rig and in the picture i was 7 or 8 years of age photo was taken at Milang in 1979. Dad told me it came from Western Australia and is the only one in South australia. so any one in WA mite no where they came from.

one more

underwater hull shape

Other stuff I've recently discovered....

Took a wander down the coast over the weekend to a little hole in the wall place that rotomolds canoes/kayaks as well as building carbon versions also.

The big surprise was a. that he reads this forum and b. he can build rotomolded boats that are 18' and are only 1.7 kg heavier than the same boat in carbon.

As you might guess....he wouldn't tell me exactly how its done, but they are almost as stiff as the carbon hulls and he can whack them out extremely quickly (4/day).

Seems the trick is that they have a very thin outer skin, a honeycomb core and then another thin inner skin....also has metal inserts for fixtures and he says he can mold centercases in at the same time if required.

This may be the way forward for cheap and lightweight boats for the class, and I intend to pursue this to see if I can't get my round bilge design done this way if the setup costs permit it to be accomplished.

Cheers
RG

Occasionally, I peruse some threads that do not really include me. And every once in a while I am awestruck and tickled by some of the postings. The post that is quoted below, really grabbed me and I think that it is very good living that allows people to experience such joy.



Isn't that just GREAT!

GARY

Great photo's and thanks for posting them Danny
regards

The cost of tools and moulds cost will probably be an issue. Still, if this type of construction results feasible, consider one boat for me instead of the plans to build it.

I think the vast majority of parents and clubs would prefer to buy an off the shelf boat or hulls if they cost less than homebuild even if it did weigh a little more. Indeed when I ran the F12 idea past my club they said they would not be interested in any boat for children that wasn't rotomoulded.

If you could get enough people interested then rotomoulding should be feasible for the F12 class.

Gareth

Forget about including any of the existing cats. There are none to be found in this range that are spread widely enough. The Taipan and Stealths were a good spring board for the F16's but in all honesty their are no 12 ft small and simple cat designs out there that could serve a similar purpose.

And yes I checked ! ( Berny !)

Tried to contact some of these classes and I concluded that they are completely dead as no reply was ever received.

And no the idea was not to get a specialized cat for young kids (8 to 10 year olds), that is the Blade 12 project. You can we please stop dragging that argument back in over and over again. That station has been passed.

An 8 year old is simply not going to sheet a 7.00 sq.mtr mainsail with only one hand (other being on the tiller). Two young kids just may be able to sail the craft with one on the tiller and the other sheeting the main with two hands.

Please Berny read the historic documentation on the F12's before making any more posts.

Wouter

This is what annoys me most about you Wouter, you say things like this as fact when I am sure you know it is just completely untrue. Of course there is a limit to how hard a seven year old can pull on a mainsheet just as there is a limit to how hard a full grown man can pull. But to try and say that is the reason you cannot have an F12 for children is just nonsense.

For another example of this kind of blatant mis information to support your own narrow point of view you only have to look at your first two posts on this thread.



followed by your next post



Just because you don't want a kids catamaran there is no need to post this kind of stuff. If you stick to telling us how good your ideas are and stop trying to put down evryone elses we are more likely to succeed with getting more people sailing cats.

Gareth

You are indeed right about the vang part, I had overlooked that part. Thanks

Fact of the matter still remains the F12 project was not started as a very young kid project and I was indeed the one who started the F12 project so I should know. It was started as a youth boat and as an entry boat to cat sailing. Otherwise I would have remained with the Blade 12 project which I specifically didn't.

And I do indeed resent the fact that in this project we have a tendency to cover the same points over and over and over again because someone like Berny is not up to speed on the status of the project. I also suspect that he is bitter over the problems his 430 encountered. I know that he publically blamed me personally for that partly, because influencial persons like myself (his words) didn't support it enough. So yes I guess I want him to shut up and lets things sort themselves out. Their is no reason why the F12 can't not succeed were the F14 failed. Reality sometimes works that way.

Now indeed, like others I think the AO-14 and 430 (F14's) are excellent designs, I just never really saw how they fitted in marketwise. I thought/think that they missed the mark in the balance between costs and what you got for it. Sorry, that is how I always felt about it. I also think that the very same danger is lurking the F12's, but that is another topic.



Despite my gaff earlier I still don't believe that the F12 as currently defined is well suited to kids (below 10 years of age) sailing it alone. If that was the goal then I would favour different specs altogether.

With respect to pretty much all the other stuff I write, I have full scientific proofs written out + experimental data to support it, others may call that "useless mathematics", so if I sound factual there then that is because I'm convinced that I am.

I appologies for my frustration showing through my writing. I know it is popular to jump the Dutch guy, but alot of it is not deserved. And I don't think others have the right to simply demand that F12 is now for young kids because they personally want it to be that way. This is sort of like the same thing you accuse me off but then in reverse. I know you want it to be for young kids, but I don't throw that in your face all the time, do I ? I guess I've heard you accusing me of "not wanting kids" more then enough by now,

Sorry !

Wouter

Now with the intermezzo by Berny and Grob (no hard feelings on my side were left, guys) can we please get on with the progress we were making.

Scarecrow was proposing to consider fixing other limits in the way we fixed the max hull length ex pintles to 3.80 mtr.

I appears there is an unspoken concensus on sail area max 7.00 sq. mtr. Can we confirm that ?

How about max mast length at 6.00 mtr and max platform width at 2.00 mtr ?

The discussion was focussing on setting a max luff limit that is shorter then having that fixed by the max mast length itself. Anyone want to comment on that ?

Lets get on with that approach, it seemed to be working well, things were getting decided.

Wouter

while I can't speak for RG, thats what he has given to all 9 of us here and thats what we are building, so at least 9 of us agree on something <img src="http://www.catsailor.com/forums/images/graemlins/smile.gif" alt="" />
Aerynt

So Gareth, help us to have a more sensible discussion about this. What do you consider to be a reasonable upper limit on the sheet tension an 8-10 y.o. should be able to manage? Can someone provide some data on expected sheet tension as a function of sail area and wind strength?

Mark,

Harken have a calculator on their website that gives sheeting forces for a given sail size and windstrength (http://harken.com/calculators/MainsheetLoading.aspx), but the point is that is pretty irrelevant as the maximum forces are more to do with righting moment than sail area or windstrength. Also there are both sailing techniques and rig designs that allow you to overcome higher sheeting loads.

The whole point of me starting this thread was to see if people were interested in an F12 design that could accommodate a larger age range by having different rigs like the BIC dinghy does. I thought that people were interested in this. I am not trying to drive the F12 to be a kids boat only I just would rather it accommodate everyone.

Gareth

Sorry for going off-track, but what is a sine wave stiffener, and how does it work?

Since the sail area is about the same as a Laser and the speed slightly faster, sheet tension should be a bit more than the Laser. Harken offers a "not widely accepted" formula: here

All seems to indicate that the same platform serves for a wide age range.

If one wants to use the same F12 for 12- and 12+ kids, two scenarios are possible:

- F12 designed for 12+: buy a smaller sail for 12- kids or have them sail two up.

- F12 designed for 12-: buy a bigger sail for the 12+ kids.
(boats for smaller kids have wider safety margins, so the extra loads shouldn't be a problem).

I guess we will be happy anyway, so age is not a big issue for me.

Then it sounds like maybe you agree with Wouter (<img src="http://www.catsailor.com/forums/images/graemlins/shocked.gif" alt="" />) that 7m^2 may be too big for the young kids. In your thinking, if there is an intention to accommodate that wider age range on the F12 platform, would it be appropriate to actually introduce a second, "junior" sail area specification into the class rules for the younger kids in addition to the 7 m^2 limit - along the lines of what Luiz was suggesting?