Yes, this is the man that you all love to hate !

But bear with me for a moment, afterall there is alot in this concept that originated in my mind. The drawing itself is mine as well.

You'll probably have noticed that the hulls look very similar to the Blade F16 hulls because I ripped those of the F16 drawing I had made weeks earlier.

The idea for this 12 footer came from Phill and he wanted a very simple boat that would be very suited to children and small adults but not look like a bycicle with training wheels.

I remember how despite my love for complex boats I really appreciated the simple and quick setup of my class 5 landyacht. So two things merged. The Blade platform with a class 5 (unstayed) rig of about 6 sq. mtr. area (65 sq. ft.). The idea was to make is really agile boat (like a laser 1) but with a much simple setup that still retained a high efficiency ratio. The laser 1 has a triangular unstayed rig. The class 5's landyacht have a unstayed rig like the lasers as well but with a much more high aspect and therefor much more efficient rig.

Later we found out that the 65 sq. ft. sailarea was very similar to the laser 1 radial rig that is optimized for light weight laser sailors like women and teens. Afterall you'll need to be 80 kg or more to hold down a standard laser-1 rig.

Some development was done on this 12 footer (later coined as F12) but it stalled, F16 and F18 design work did take up alot of time and effort.

So here we are. I still think the basic idea has alot of merit and over the X-mas hollidays (I was fed up with control engineering design work of my more mundane weekly endeavour) I worked some extra portions of this design out. Mostly trying to make the design simpler and easier/cheaper to build.

I believe that if this thing is to fly that it must be really easy to build and ludicrously inexpensive to market.

Like I said the rig is pretty much of a class 5 landyacht and I know that reasonably well. I have measured mast several setups and I think I have the rig sorted out designwise. It also looks like this boat can be rather fast despite its strict emphasis on simplicity if one condition can be satisfied. Overall Lightweightness !

50 kg ready to sail would be perfect ! 60 kg would be acceptable. Higher will be unsufficient as then it requires more sailarea and heavier component thus leading direction into a weight trap.

The mast itself looks to be buildable in aluminium (out of standard round sections) for 8.5 kg. The (sleeved) sail and boom should not be more then 4.5 kg overall. As the rig is unstayed it should be buildable for 13 kg or less. That is pretty lightweight. And added advantage of the class 5 rig is that the mast is build up out of shorter components by fundamental design. Therefor the rig can be "collapsed" into smaller sections just like the laser rig. This takes care of one major problem point mast -length and easy transport.

The beams should not be more than 80x2 and the whole platform should not have to be wider than 1.80 mtr. Probably 1.60 mtr. is better. That is if you look at the ease of flying a hull, a key component in thrill experience. But either way the beams themself will not be heavier then 2.5 kg a piece, excluding additional fitting of which there are hardly many as this is a simple boat. That makes 5 kg for the beams.

I have a very simple traveller setup that is both very cheap and effective. I have that system on one of my other landyachts. I never believed it would work but it truly does. The whole system is just two blocks with a becket and a length of line. No cleats, no rails, no cars. As such it is excellent for this F12 setup. Mainsheet and downhaul are integrated and should not weight more then 1 to 1.5 kg.

I've also done some stress analysis and it looks very doable from many angles. There are only two problem points. We are now only left with roughly 30 kg for two hulls. That means 15 kg per hull.

problem point one :

How to make a hull by inexpensive means that only weights 15 kg. I believe that the 12 foot length is a very helpful factor here, just as the unstayed rig is. But cheap and inexpensive production techniques pretty much mean a hull made with core-matt instead of foam. As in spraying a core layer of chopped matt and resin on the outer skin and than finishing of the inside with another layer of glass. Will that allow a 15 kg hull of 12 foot length ?

problem point two :

How to fit the mainbeam to the hulls. The mainbeam will be under significant torsion loads that all need to be taken up by the beam landing if the boat is to remain simple. Calculations will only help a little bit in this area, significant real life testing need to be done to really find out what will work and what won't.


I also measured up the roof of my car and a 12 ft by 6 ft is really cartoppable when fully assembled. Afterall the laser 1 itself is 13.5 ft by 4.5 ft. But again lightweightness is key as pushing a 50 kg platform on top of your car is alot harder then 30 kg.


Personally I see this concept as very promising. At least up till now I have not really found any serious hang-ups. Maybe we should indeed persue it further.

However I do propose to forget about 14 ft and go straight to 12 foot. This will not carry a family as neither the laser-1 will. We are not looking to design a competitor to the Hobie wave.

Without clear concent I can't use any F16 hull data for the F12 hulls. So somebody, somewhere has to come up with a decent 12 foot hull or persuade Phill to draw of the F12 hulls. Without Phills concent I really can't work on the hulls. All the other stuff is unrelated to the Blades and so I can work on them and make the findings public knowlegde.

But far more interesting at this time is solving the beamlanding issue. For that even simple test rigs can be build and used. That'll save us wasting time and money on hull that we'll break.

I propose to start on that first, any takers ?

An alternative could be to get the timber Pixie building plans (a 14 ft 100 kg catamaran) and use that as a first test bed. Or maybe the 14 ft paper tiger building plans.

Does anybody here have experience or data concerning core-matt hull building. ?

Gareth, are you willing to provide us with some Michlet hull drag data ? Preferably compared to f18 hull drag graphs ?

If we forum members work together on this one then maybe some really exiting may develop.

Wouter