You're missing a couple of the cool things about Optis at least the experience we had with them. My kid could safely single hand the Opti at age 7 and 50 lbs.

At Bay Week (Put-In-Bay Ohio) where my wife and I were competing as adults, my son took his Opti out after we were done racing for the day. He would sail his Opti from the Yacht Club over to Gibralter island and back. He then started taking his kid friends out, one at a time in the Opti. That was one of the coolest, most esteem building things, I have ever seen a 7 year old do.

The most fun we have is playing ball tag, or tag, or other games like that with the Optis. Again, the cool thing is that all of the kids 7 to 13 or 14 are fairly even in the Optis. It's not how fast the boat goes it is that they are all the same.

And finally, it opens up options for breeze that a bigger boat would not. At 9 Joey went to Buffalo Canoe club for Opti midwest. The kids were out in an honest to god 18 knots of breeze gusting over 20, with 3-4 waves, and the occasional 6-7 footer coming through. It would have been pretty tough for him to handle anything bigger in those conditions at age 9 and weighing 70 lbs or so.

Now then, if it's blowing 3-4 and the water is flat the opti is not an exciting boat. But get 6 or 8 of them together to play and anything is fun. The great thing about the boat is the small size, that the kids (young kids 7 and up) can totally handle it themselves, from rigging to launching to righting.

Thanks Phill,

I think I have a few more issues solved now. I'll mail you later. The trick is indeed in planing the corner ceder rods to the right planes. I'm thinking to have the prototype made using stitch and glue and then use the sides of this single hull to plane (route) the ceder to the right angles allowing the other hulls to be build much faster. This will really kick in when a group is building multiple boats.

It also means I can look again at the multichine wave-piercer hull design ! And I really want that because it can be made to look really good.

Additionally the chines themselves (especially the one on the side panel) will make the hulls really resistant to hitting things as all V-ed shapes are.

It is looking good.

Can you give some feel of how much a F12 hull will cost in material (using the 5 panel multichine hullshape using shaped chine rods).

A rough guess at this time will do.

Wouter

I'm not.





Go ahead !


Wouter

wouter,
This price would depend on the final design, ie are the hulls sheathed in glass? do you use stringers in the chines or fillet and tape? etc, I would expect you to be able to build a pair of hulls for around $500 Aus.

You're paying around $40 to $60 per sheet of 4mm ply and there is 3sq meteres per sheet. You will probably need up to 4 sheets. $6 to $10 pre Metre sq for glass. $15 to $20 per litre of resin depending on the brand and size it is bought in.

I think you will find it cheaper and lighter but more time consuming to fillet and tape the chines.

Once you have a final design you should be able to get a better idea.

Hi Wouter,
been away from my pc for a few weeks and bumped into this thread, to answer your question :
"Currently I'm thinking about a max sail area limit (single sail) of max 6.0 sq. mtr. on mas 5.25 mtr masts. As for this area and mastsize I know the landyacht rigs will hold (no further design work involved here). But will that be a good max size for the people looking for cheap second hand surf sails."
Typically a 6.0sq.m sail will be rigged on a 430 mast with a 15cm extension, giving mast length of approx. 445cm. Race sails will be shorter in the luff and longer boom length while wave sails will be set on short booms with slightly longer masts. My Neil Pryde Race sails are 5.9sqm, 445cm mast incl. extension, 186cm boom. My 6.6sqm is on a 468cm mast, 197-200cm boom. Both have camber-inducers which I think would be unsuitable for use on a catamaran, when gybing or tacking you really have to bang the sail over to get the battens to rotate - on a cat in winds less than 15knots this might be almost impossible to do unless you stood up and man-handled the boom.
The problem with allowing windsurf sails in is that while some folks will buy cheap stuff on e-bay, others will buy full-on race equipment that will easily cost much more than the rest of the boat.
I would suggest that if you allowed windsurfer sails to be used you set up quite strict criteria, I would disallow full race or speed sails, no camber inducers. Stipulate the max. carbon content of the mast at around 40% - a 100% carbon mast can cost 4 times what a 40% carbon mast costs. Allow only aluminium booms - again full carbon booms are really expensive compared to alu. booms. If I were drawing up class rules that allow windsurf sails to be used i would even consider making up a list of permitted sails, or stipulate that only non-cambered free-ride or wave sails can be used.
You could also limit boom length to 190cm, mast length to 450cm and sail size to 6,0sq.m, that will stop vastly different shape sails from being used (to an extent). The problem is that windsurf-sails are so different in shape, outline, draft, twist and aspect ratio depending on their intended use, which is why I`d make up a list of permitted sails, like the Naish Vantage or Sprint, and similar sails from the other manufacturers. Have a look here :
http://www.naishsails.com/products/sails/index.html
This gives a good idea of how different the sails can be - the Naish Boxer would fit all the criteria I have mentioned but is vastly different in shape to the Vantage or Sprint.

Also need to consider - if you stipulate a max. sail size, nothing to stop folks from having 2 or 3 sails that fit in the criteria, so if it`s blowin` hard they could rig a 4.7sqm or 4,0sqm sail and still race. Good for versatility of the class, bad for keeping costs low. Just things to consider.
Oh yes, boom height is between shoulder to chin height. Good luck with measuring that one.

Hope this helps..
Cheers
Steve

Thanks Phill you are a great help as always.



The basic concept is here, I'm not working out the exact dimensions. I'll get back with you on this when it is ready for peer evaluation.

Wouter

Thanks alot Steve,

It is true that no windsurf rig has a mast longer then 5 mtr then ?

It is also true that by far most windsurf rigs have sail area's less then 6 sq. mtr. ?




This is also the complained of the "standard" landyacht sailors. The only camber inducers that do work in my knowlegde are found on the moth sailboats and in windsurf sails. Currently I'm not considering camber inducers, but I want to leave the option open if we do need them later to get the rig to have 15 % draft. So I'm not ruling against them at this time.

Class 5 landyachts aren't using an camber inducers and are just a quick as "standard" landyachts while having less sailarea and less width. So it appears that a good sleeved sail design is possible without camber inducers.




Some will ry to build the hulls out of Gold. That is their decision, but it won't help performance in a significant way so I ignore such money wasting projects. I'm not afraid of carbon either.

I can't disallow race sails as that is impossible to control in a class like manner.




I want the ability of different rig as that would allow the really young and light sailors to equal the playing field with the older and heavier folks. There will be a rule however that limits the use of only one sail and mast combo per event and during the whole event. This should prevent multiple rigs developped for narrow wind ranges.


Thanks for you help again

Wouter

Going the windsurf sail route is a real bonus as when its really blowing the kids will be out on their windsurf boards plus there are heaps of not so out of date sails around at a very competitive price, fashion is very much a real thing in windsurfing and last years sail just may not have that visual edge as the previous years. <img src="http://www.catsailor.com/forums/images/graemlins/tongue.gif" alt="" />

My thoughts exactly and as such I looked at how my design can be made to accept a windsurfer rig. Personally I have about 4 windsurfer rigs in my shed, so this effort is not completely without benefits to myself !

Turns out that fitting a plain windsurfer rig to what I had already designed was pretty easy. It will perform less then the real F12 rig, as the surfer sails are probably a little to flat, but then again most are not concerned with that.

Actually a standard F12 can be made to accept the windsurfer rig without large modifications. Pretty much adding a fitting to the mainbeam to take the foot that is on the windsurfer mast itself and fixing a ring to the boom that goes over the mast support. If push comes to shoove then even two lashings can take care of this.

The mainsheet will remain as it is but won't be run through the first block near the mast (= downhaul on the standard rig)

Wouter

Hi Wouter,
It is true that no windsurf rig has a mast longer then 5 mtr then ?
No, Formula or race sails are set on 490cm or 580cm masts with a mast extension, varies according to sail size. Check out Neilpryde.com - sails - racing - RS6 for specs. They have a 12,5sq.m sail that has a 6,1m luff length and 2,93m boom, so that answers your other question. (It is also true that by far most windsurf rigs have sail area's less then 6 sq. mtr. ?) They make a 5.8 and a 6.2sq.m sail too, so if you want to limit the max. sail area to 6sq.m, you`d pick the 5.8 and the luff is 440cm, boom 187cm, so stipulating a max luff length of 450cm and max. boom length of 190cm should work - but check out Naish, Tushingham, Ezzy, North and Maui Sails websites and cross-check their specs for sails under 6sqm just to be sure they would all fit into your class rules, or you will limit buyers to one or two brands that do fit. I would do this for you but lack the time right now.
You have raised an important point - most windsurf sails other than race sails have very little draft and a lot of twist, which might make going upwind quite difficult on a cat, since they travel so slowly (JOKE!!!) They are mostly made for reaching which most windsurfers do most of the time, it`s only the race and Formula guys that actually try to go upwind.
Check out the twist in this pic of a Naish Stealth race/speed sail..
http://www.windsurfingafrica.org/Portals/7/Gallery/Album/159%5CDSCF0468.JPG
Cheers
Steve

I must have missed it in all the earlier posts but how do you propose to support the freestanding windsurfer mast at the mid beam? Or, will it have some type of stay system added to the tip? You might be able to run a windsurfer boom on it and attatch short stays to the front and side of the boom, hook a mainsheet to the back of the boom. Is that what you had in mind?

Pretty simple really.

I made the design to support an unstayed class 5 landyacht type of rig. Currently there are 2 alternatives being considered. The first was discussed in the thread and involves glue.

The second is basically a support structure of two tubes working together with the mainbeam and the lower portion of the mast. You can interprete it as a mast with extreme low twin forestays that are also able to withstand compression (something wires can not do). The mast itself will then still need to be made in the class landyacht way. So in boat behaviour and performance there is no difference between these two paths.

Neither is there a difference in the way a windsurfer rig is fitted to the boat if so desired. Just secure the foot of the windsurf rig to the mast stub at the bottom and the boom at the top of the stub. The mainsheet system is then replaced by a setup as used on skiffs like the 49-ers.

Actually is should be possible to jury rig a windsurf sail to an F12 build to take the class 5 rig.

See the drawings and pictures to understand fully what I mean.



I look alot like the ice-flyer landyacht did it, see picture :



The mast stub is actually just the bottom section of the class 5 yacht mast. So in fact you can just take of the surf rig and fit the original rig again. The mainsheet system changes then back to :




Wouter

Guys,




I don't have time to investigate all the different types of wind surf rigs.

So who wants to take on this job and work-out a summary of what is often used/available on the (second hand) market in the way of Race and Formula sails. Also check what sail area's and luff lengths (+mast lengths) are used in 8-15 knots conditions. Boom lengths are important as well.

The F12 as it currently stands will be 120 kg (55 kg craft + 65 kg model sailor) and as such you also want to investigate the heavy boy surf sails (power).

Then get back to us and I will incorporate this windsurf sail option into the design.

If nobody takes this job on then I'm going to forget about it. Afterall I'm spending heaps of time on other aspects of the design already.

Wouter

Hi Wouter,
"So who wants to take on this job and work-out a summary of what is often used/available on the (second hand) market in the way of Race and Formula sails. Also check what sail area's and luff lengths (+mast lengths) are used in 8-15 knots conditions. Boom lengths are important as well. "

VERY brief summary - Formula Racing requires that you register 2 sail sizes for an event - you may only use these two sails at the event. Most guys register a 11/12,5sqm sail for light winds and a 8,5/9sqm for heavy winds. Light winds are 8-15knots, where up to 12,5sqm sails are used, from 15knots to 30knots (cut-off) they are using 8,5sqm or 9sqm sails.
I think I`ve answered on the luff length and boom length questions in a previous post on the size of these sails, but a quick look at www.neilpryde.com - sails - racing - RS6 will give a complete table of sail sizes and their specs, and will take you a lot less time to look it up than for me to figure out how to.. wait a minute.. see attachment !
Hope this helps.
Steve

F12 enthousiasts,

At the following link I have placed a document that is intended to set the first steps in getting this design project structured properly.

www.xs4all.nl/~whijink/formula_12/The_Formula_12_sailboat_project.doc

It is a word 97 file.

This 280 post breanstorm session we had over the last 7 days was both inspiring and overwhelming. But the time has come to make sure that the efforts of one volunteer build on those of another and that with each step we get closer to completing the design and building of a prototype.

I'm back at work so I too will have to work alot more efficiently then I have done of the last couple of days.

On the work done already I say that this project has a really promising outlook. Sure we'll encounter some setbacks and hick-ups along the way but the numbers have already shown that this basic F12 setup has ample merit. To name one example. Performance approaching that of the H16 is expected and that is really fast for a 12 foot design. Also the goal of 3000 US$ or less seems very reasonable even with bought rudders and such.

So I propose to start implementing the steps described in the document and get this project under way properly so mangan can build our prototype !

Who is with me !?



Wouter

I would love one for myself....but I don't think I would put my grandchildren on it. Kids run into concrete walls and rocks and pilings and docks, and maybe even into people when going to and from the beach. Kids are more interested in "playing" on a boat, capsizing it and righting it, using it for a swim platform to jump off, etc. They don't always pay attention to where they are going and what is in front of them.

If the boat is actually FAST, they are just more in danger of hurting themselves or others and damaging the boat itself.

If they actually sail it, I can just visualize them disappearing rapidly over the horizon, while I don't have a powerboat to catch them and make sure they can get back. How would I explain this to my daughter?

The F12 sounds great -- for the adults and for more experienced youth sailors.

Again, some of us are wondering exactly what the goal is for this new boat, what is the target market? If it is for youth sailors, what age range are we looking at? What ability level? Is a relatively high-performance boat the right boat for teaching young kids who have never sailed before?

The nice thing about the boat is that even if there is only a relatively small window of time where it works for kids, and only a certain category of kids, the adults who build it can continue to play with it forever.

Like I said, I would LOVE to have one myself. <img src="http://www.catsailor.com/forums/images/graemlins/laugh.gif" alt="" />

Let's Roll!!!

Goody! Now I just have to find somebody to build my F12 for me. I figure since it is going to be so fast, I can use it as a chase boat for my grandchildren on the Wave. That will be perfect! I'm very serious!

I would try and keep the rules for the use of windsurfing sails as all encompassing as possible. So as not to exclude many of the cheap rigs available, a quick look on the uk ebay site showed over 30 rigs of all sizes and budgets. The system I use on my biplane multi with windsurfing rigs is very similar to iceflyer, with a submast and it works well with good gust response. As mentioned the camber inducers sometimes need some help in light winds but its no big deal.

Gareth

Everybody read the whole post as I'll answer several our your questions in one go. So this post in more then a reply to Mary.

I would love one for myself....but I don't think I would put my grandchildren on it. Kids run into concrete walls and rocks and pilings and docks, and maybe even into people when going to and from the beach. Kids are more interested in "playing" on a boat, capsizing it and righting it, using it for a swim platform to jump off, etc. They don't always pay attention to where they are going and what is in front of them.

If the boat is actually FAST, they are just more in danger of hurting themselves or others and damaging the boat itself.





If kids don't keep themselfs to the area limits then even on a Wave they can get lost over the horizon before you have time to recognize it and catch up with them. The only solution that would COME some way in addressing this is to give your grandchildren smaller sails to sail with. Adjusting the mast for thing is really not difficult nor at all expensive. I refer to the mast building plans given earlier in these discussions. Making yourself a more flexible mast tip for a smaller (kiddies) sail will cost maybe 2 hours of time and some 50 bucks in material. Most of the time is spend on getting the standard alu tubing from your local hardware store. The components are just standard alu tubing, packing tape and a handfull of stainless screws or monel blind rivets.

The only real cost is purchasing a smaller sail, but you should be able to do that first time round when getting the boat.




This is for which the fully blown F12 is geared towards. Although it will not carry the family. Max Two persons at the time. It will float well of course with more then but performance is completely out of the door.

For the really young kids it is intended to have two of them on board. This will make them less frightened as well in my own experience because as they feel supported by eachother. Smaller sails specially made for truly young children are also a serious option. Again this is a formula class and in such a setup you may always sail with less sail area then maximally allowed.





The design can't really be designed well unless we gear the proces totally to crew weights instead of age groups / experience levels. These latter points are simple to vague to design a boat too. Additionally because of its small size the F12 is relative sensitive to small design changes.

Therefor we really have to specify a weight range for which this design is made.

Currently I've personally identified the range 55 kg to 75 kg as the main target range with good performance. In this range 65 kg will be the design crew weight meaning it has been completely optimized for that. Sailing lighter is never really a problem, sailing heavier is and so 75 kg is closer to 65 kg then 55 kg is.

From my personal experience European teenagers are right in this weight range from going from 12 to 18 years of age. As such it is a youth boat.

When used as a kids boat, below 12 years, it really should be sailed by a crew of 2 persons. I think this fits in nicely with the "playing with other kids" attitude as described by other posters.

Two small kids will easily combine to 55 kg weight or higher. Using the medical overweight-underweight rule I find that a kids of 1.25 mtr length (4 feet) will already weight 30 kg's. Making a crew of 2 such kids already 60 kg's and very close to optimal weight.

Note that there is no rule on how many may sail this F12 ! So two small kids can indeed race against a single adult and have a pretty fair race.


The design is intended to still give reasonable experienced crews a thrill. For truly inexperienced persons the boat allows a more experienced adult to come along and thus work up skills but even more importantly confidence. The boat is indeed really simple and most be compared to the Wave in simplicity. It will however have a few smart tricks to make it significantly faster. Of is these things is a traveller system that allows proper sail trim. This traveller costs, and I'm really not kidding, 5 bucks and you can't hurt yourself on it.

Of course you don't HAVE to use the traveller system So it will be fine for novice sailors who only have to steer and sheet and get forget about everything else. It will be a better platform for novice sailors then a monohull as it is much more stable and more predictable. I think it will be excellent in this role. You certainly can't death role the F12.





This is one reason why the F12 is made performant and carry up to 75 kg of weight well (in a racing sense). Once they get bored with just crusing about then they can work on getting max speed out of it and maybe even try to beat mom or dad around a few harbour markers. The F12 is more then a kiddies boat and as such will not easily be outgrow by aging youths. Pretty much the only real aspects on which they can outgrow the boat is by gethering alot of body weight. The boat will be able to carry up to 100 kg without a fuss but it will not be as performant anymore.




As do I myself !




In all honesty, you can build it yourself. The only REAL effort will be the hulls. But I'm sure a building group like the one around flatlander (john) can pop out 2 more hulls that you can finish out into a full boat. I trust you are handy with a sewing machine ? If so then you can just make your own sails and safe a bundle. The rudders come off the wave and the mast and trampoline you can easily make yourself as well. It appears that you could be getting one like this for less then 1000 US$. The sail and rudder, if new, are halve the cost. Now you don't have these costs it can be really inexpensive.


Gareth,

I'm extremely interested in the camber inducers. The design will progress without these, but I want to have them as a fall back option if getting sufficient draft proves difficult.

Are you willing to help us out in this respect ?



Wouter