I'm concerned about using windsurfer rigs/sails. The camber is built into a windsurfer sail when it is initially rigged. The only control a windsurfer has is basically the traveler. I don't think this will give suffiecient gust response especially for a kid.

I'm thinking a boomless rig like the Bravo or like the N6.0 may be the answer. You could even roll the sail around the mast to store it. You could also even shorten sail by reefing it around the mast.

Oh yeah, And I think a Hobie Bob type device would be a requirement. I know the kids around my lake like to go out and turn their lasers over all the time for fun.

Mike Hill
www.stlouiscats.com

Good luck expressing any concerns.
This has quickly turned into Wouter's pet project.
There have been a number of issues brought up that are quickly dismissed and the design pushes forward based on what Wouter wants to do.
After reading the word document I'm amazed at how information can be interpreted so differantly.
There have been close to 300 replys between the two threads.
There are a pretty equal number in favor and another group expressing concerns.
The paper says that without this boat that youth programs will be hard pressed to succeed.
It says that the five qualities, as seen by the self nominated project manager, are not met by any boat out there.
It also says the boat must be able to keep up with a Hobie 16. Why does that matter unless you have a personal agenda.

John's(flatlander) very well meaning and full of merit original post has turned into Wouter's personal ego trip.

If John, phill, matt or jalani want to push forward then they should.
They all seem resonable, probably actually have kids and understand the very real concerns should be considered.

Do we all want to read how Wouter is the father of the F12 forever as we do with the F16?

I thought we were an autonomous collective...

That's how I see it. Phill stated his plate is too full with summer and Blade responsibilties to pursue at this time. I'm really just an innocent bystander in all this and do appreciate Wouters effort. I can stand him taking credit (just add a grain of salt) for pushing this through, heading in a direction, consolidating information AND documenting it for more creative discussion. Otherwise it may have been a lost post.

If you go read the original F16 documents you'll see the same reference to a colaborative effort.

I'm guessing the H16 reference was influenced somewhat by my harping here, maybe faster than the rotomolded product available is a better way to state that.

Whatever your thoughts on Wouter and his agenda, he, and Phil are uniquely qualified to spearhead this IF you really are interested in the F12 becoming a reality. They have just walked this path with the F16, had to address many of the same questions expending much time and effort. The naysayers came out in droves claiming the F16 concept would never work (some are still trying to call it a “fad”)…well guess what? It’s working…slowly and surely gaining momentum.

Now the idea of a F12 is receiving attention and the need of a Project Manager is obvious… but how many have the time? …the contacts?... and the experience? to make it “happen”. How many who qualify have volunteered?

Its not that others couldn’t do the job, its just most would have to start from a blank screen. Wouter/Phil(with input from a host of others) already have the “F 16 model” honed over the last 5+ years…all they have to do is insert the F12 variables. If the goal is truly to benefit the kids, and get this thing off the ground as quickly and efficiently as possible, Wouter may be the best man for the job. Is it really important which ego gets credit if youth catamaran sailing is benefited? While this is a definite team effort, it is very advantageous to have people at the helm that have sailed these waters before.

“There have been a number of issues brought up that are quickly dismissed and the design pushes forward based on what Wouter wants to do.”

Many of these same issues were exhautivly considered and discussed to death when setting up the F 16 class…A good Project Manager has to be able to make decisions, even when they are unpopular with some on the team. As you know there is never going to be a point where everyone is 100% happy…that’s life.

At some point one has to decide whether this is just an intellectual exercise like most ideas on the internet, or push forward to make it reality.

Regards,
Bob

About the wood: I know some guys who have built the little Cape Cod Frosty boats. http://www.capecodfrosty.org They buy luan door skins and cover the bottoms with very light cloth, then epoxy. Not fiberglass cloth, just any colorful print and very light weight. The hull looks likes like a shrunken Opti and grown men race them in the winter...in New England! So my question is, do we really need to use expensive marine ply or can we get by using cheap off the shelf stuff from Home Depot, with lots of epoxy to stiffen it up? Or, is the marine ply essential for strength? BTW, most guys who build wooden Opti's use regular plywood, not marine ply.

The discussions I've seen regarding using Luan (door skin, or flooring underlayment) for small boat building is that a lot of people do it, and it works very well as long as it stays encapsulated. It doesn't last as long if it gets wet. It's well finished on both sides and relatively free of voids. Best use would be for a boat you're not going to put a lot of investment into. It may be a good choice for a boat like this, especially if the hulls are easy enough to build - if one goes bad because the encapsulation was compromised, simply build another.

Exterior grade ply would also work fine for most applications - the thing is to make sure the grade you are using has minimal voids in the middle layers. I believe A/C has less voids than A/A if I remember right. It certainly is used in a lot of applications for plank on frame. I might be leary of it for tortured ply designs, as any voids could cause problems with bending the sheets. The glue used in exterior is better than that used in the luan.

Mary,

My idea was to have a pocket in the head of the (squaretop) sail where on either side a sealed piece of plain styro foam can be placed. A 500x150x50 block on either side should be enough to provide 7.5 kg * 6 mtr counter leverage = 45 kgm. That would be the same as a 1.60 mtr tall 50 kg sailor hanging of the righting line.

And when done this way it will not look badly at all and it will be aerodynamic (end plate effect anyone ?) . Another ideas is to stuff the top of the mast and the sleeve of the mainsail with shaped (and sealed) styrofoam.

As styrofoam is commonly available for a few bucks you can just replace it now and then.

Wouter

Jake,

You willing to analyse and work out this branch of the F12 you feel is lacking attention ?

If so then I'll welcome your report and you can rest assured that it will looked at really hard.

If not then I'm afraid there are more pressing things to attend to at this time


Wouter

When talking about Luan and similar materials for boat construction, one has to consider the cost savings of the Luan over Marine Gaboon Plywood in contexts of the complete hull construction. It is easy to dismiss the true cost and say if it breaks I’ll just build another one…but let’s look a little closer.

You have the expense of:
1) Plywood
2) Stringers if any
3) Bulkheads
4) Epoxy resin for glue sealer and fairing
5) Fiberglass tape for Stitch and Glue
6) Cabosil for glue and glass bubbles for fairing.
7) Brushes for applying the fiberglass cloth
8) Sand paper
9) Primer & Paint
10) Gloves/mask


The labor of:
1) Laying out/cutting/fitting the plywood panels
2) Stitching the panels together
3) Applying the cloth tape
4) The fillets
5) Cutting/fitting/installing the stringer/bulkheads
6) Cutting/fitting/installing reinforcement for the beams
7) Cutting/fitting/installing the decks
8) Fairing the hull for paint
9) Priming/painting
10) Assembling the boat ready for use.

In the grand scheme of things, the cost of quality marine plywood (which is going to provide stronger, longer lasting, lighter, fairer hulls) is money well spent.
How much is your time worth?
How is the child going to feel when the boat they spent so much time and effort on starts falling apart because dad/mom saved a couple hundred bucks by using cheap plywood? Remember that kids tease unmercifully.
What are we teaching the kids when we take “short cuts”?
What are the chances they will want anything to do with making a replacement for that delaminated hull?
Never enough time or money to do it right the first time but always enough to do it a second time….?

My dad taught me…”Do it right or don’t do it at all”... it has served me well.

Regards,
Bob

The F12 will feature a different rig then the windsurf as standard. The windsurfer option is just an alternative to allow others get to the water at a minimum of expense or effort. It is up to them if they decide to go that way.




No full length battens means significantly less sail are (about 30 % less) and a sail shape that is very hard to control. Both of these translates directly in to a slow craft with ill mannered behaviour like difficulties tacking. A boom less rig has many disadvantages which all outweight being "hit" in the head by piece a 750 gram alu tubing. Additionally the bottom sailshape of the sail is crap in anything other then pure upwind work and such a boat will pretty much as bad as the laser funboat.

Again this is the laser/hobie way of doing things and we want a boat that is significantly better. Otherwise everybody go out and buy Funboats/Bravo's


Wouter

Pat,

Is it you that has a personal problem with me ?

Are you practically saying that I do the F12 so I can get back at the H16 ? When you wrote :





Additionally I truly am the father of the F12 design.

The drawing that started all this is mine. The concept design that was depicted was also mine. Phill came with the idea of doing a small catamaran but the basic setup was my reply to his request. This started a few years ago.

Halve the design was already finished before discussion even started on this forum as Phill and I had been working on it over the last few years in between other projects like the F16's and F18's. Some prototyping of hulls had already begun, as Phill mentioned in one of his own posts.

So even if I stop right now, I 'll still be the father of this design together with Phill. There is no way around that.

Maybe you should also consider the fact that many aspects of the design have already been investigated by Phill and myself in the past. That is why I can dismiss a good portion of the suggestions; we already know there is no merit in them.

Why is it that you don't want to make use of these experiences gained, it is only because I happen to be Wouter.

By God it seems like that.

Now this is my last reply to you, I'll ingore you from now on as clearly you have nothing valuable to contribute.

Wouter

Over time I'm came across many boat building pages on the net and a good portion of designers and builders seem to suggest that normal ply can be used succesfully if small defects are not magnified by having the material loaded up to its limit.

Personally my take on things is that if the F12 hulls are truly easy to buid then it may well be worth the risk to just use normal ply and see how it holds up. If it does crack or something then it can be repaired relatively easily and then the hull can be glasses over.

Once a hull is glassed over the inferiour aspects of normal ply should really not be a major issue in my perception. But it will be best to check with Phill on this matter. Afterall he has 25 years os experience in building these things.

Wouter

think if you are going to invest 100 hours in building a boat, the cost of okoume is not much. The other thing to consider is that it is about 10% lighter then luan and 30% lighter then douglas fir or baltic birch.
I have built small boats out of okoume, marine rated douglas fir and other stuff out of luan. Luan is way inferior in quality. The faces are very thin, the core is thick and has voids, it does not like compound bends at all.

Do not cheap out on the plywood.

I was looking at the design and I think if you are covering it with 6 oz fiberglass on the outside you can use 4 mm okoume for the hulls no problem 3 mm might be pushing it.

A 5 piece stitch and glue hull 12 ft long with scarfs, and no daggerboard trunks and with full sized templates I would guess you are looking at around 40 hours per completed hull. Add another 20 per hull if you are super anal about fairing it and painting it with awlgrip or similar.
Build the rudders out of 2 pieces of 1/2" baltic birch. Make a design and have someone cnc the shape, then glue 2 halves together, run full lenght Uni carbon down the middle of it on each side then glass on one layer of 6 oz cloth and fair it.

If you get someone to make the cores for the rudders, it should cost ~ 150$ for the cnc cutting. Everything else can be built.

Just my thoughts.

P.S. do a web search in multihulls world about 10 years ago a german guy wrote an about making a 14 ft cat that weighed ~100 lbs to sail in indonesia on vacation. He shipped the plywood precut and built it in 2 days in indonesia and sailed it around the islands for a few weeks. He used a windsurfer mast.

Cheers,
Eric

We'll let the jury decide.

I have a problem with how you treat people that are offering advice based on their experiences.

I have sailed every regatta and fleet race for the last three years with a crew under the age of 12.
That is something in the area of 250 individual races.
I have things to offer to the big picture you can't even begin to understand. I have tried to offer constructive input.
Phil and others have acted in a professional manner when questions were asked. I have no problem with him or the project.

As for the word Hobie. We might as well be ringing the bell for Pavlov's dog.

If you look back through this post you threw the first stones.

Everybody !

Posters like Eric Anderson with good info PLEASE take the time to type out your comments in a Word document and send it too me. Then I can post it on my website for all to read and improve access to data for everybody.

In the last 24 hours we have gone to 337 posts from 278 ; that is 59 posts in just under 24 hours.

I can't archieve that much info in a proper manner. Everything needs to have a context, source and listing of assumptions in order to make this stuff understandable say 2 or 3 months down the road. Alot of context is currently provided by the structure of this threading but that WILL be lost over time.

for an example look here :

www.xs4all.nl/~whijink/formula_12/F12_Crew_weight_analysis_vs_1_10012007_Wouter_Hijink.doc

If we are to make use of all your contributions (which I really do want) then you have to structure you contributions and supply then to the project in a well developped and standardized manner.

Otherwise the chance are that your comments will be lost. This is a huge pile of work that somebody (as in ME) has to work through next to me own design work.

Wouter

The given set of rules are just to give you an idea of what is going on. I think there are still to undevellopped to even use for actually building prototype. I've identified a few more loop holes that need to be close. Also the cube-square analysis provided some insights that need to be dealed with. We may have to lengthen the hulls from 3.65 to 3.90 mtr. That 4th power scaling factor that is very important from a dive resistance point of view is limiting our sailarea-mastheight combo to a rather slow boat. Lengthening the hull from 3.65 to 3.90 mtr makes a significant difference as the 4th power is such a stronger relationship. I'll try to write this out in a word document and publish it when I find the time.

Wouter

Wouter, I probably missed it in all this, but what is your web site address?

Wouter, do you think it would facilitate your project if there is a separate forum for the Formula 12? Rick is willing to create a forum for it, if you would like.
Let us know.

I would be very thankful if contributions beyond simple "Hey what if ..." are worked out using this template.

www.xs4all.nl/~whijink/formula_12/F12_Crew_weight_analysis_vs_1_10012007_Wouter_Hijink.doc

I used this template to formulize the first entry into this open source design.

I deals with the expected body mass and body lengths (latter being closely related to age) to get a feel for at which F12 crew weight range we have to design this F12.

The advantage of such formalized setup is that if somebody comes along and wants everything explained to him again we can just give him the link.

If he disagrees then he can work out a counter analysis and present that through the same channels. Then the two articles (viewpoints) can be maintained side by side and in time the better one will be incorporated into the design. This is the only way to keep this discussion somewhat under control.

Also Anybody having critique but not making any properly developped counter analyses can then be effectively "processed" and asked to stop wasting time of people who do actually research this stuff in a scientific manner.

I'm looking forward to your contributions.

And yes up till now it was easy, the hard work has just begun ! <img src="http://www.catsailor.com/forums/images/graemlins/grin.gif" alt="" />

Wouter


P.s. when you read the article, take a look at the table and see how the beginning of singlehanded sailing starts just when the doublehanded sailing becomes sluggish. In effect small kids start out doublehanding the boat and when they get too old and big to do so they are ready to start single handing. These two regimes seem to link up nicely.

Wouter