KARO footy

I would like to share my footy project, called karo, my intent with this one was to create a footy wich can be “air build”, and is competitive. Eventually will make a simple set of plans.
I’ve been thinking what would be a good hull shape wich would allow one to have control over a boat if it would nosedive downwind, while the boat itself wouldn’t lose much speed…
…it seemed that the best solution would be to have quite a slim boat with a high bow, wich pierces the water when nosediving…the bow should be so high that the water wouldn’t flow over the deck.
I also tried to make the waterline as long as posible…so i “turned” the boat diagonaly(in the box), and nose down. In order to fit inside a box nosedown the bow had to be reversed, and that aded tumblehome, wich was good becouse there were less worries about the winds efect on a “tall” hull.
For the build i didn’t do much math, just started with a round camber, and then cut the sidewall till the boat fit into the box.
I’ll write more about its handling & performance but for now let the pictures do the talking:

The rudder u can se above is not legal for this boat, but for testing it was allright, the riggshown = 1350cm2
The total weight is 455g with a 300g bulb…
And some action:


To continiue, once on the water the boat has just a little bit of weather helm, wich i find good.
Up wind it goes good(the wind doesnt seem to affect the tall hull much). But downwind is where it shines, becouse even if it is very overpowered, it keeps on going, burrying al 9 cm of front freeboard. But it does require a rudder that is at least 15cm long, so some of it still stays in the water when the stern is lifted.
One issue i had was when reaching( 3rd sailing shot),the boat would bury it’s bow, and the lateral area of the hull shifts forward…so when you want to bare-away, the rudder lifts the stern out of the water and stalls…
…to awoid that the boat has to be depowered, losing speed, so the bow goes up, and it bares-away…
…i haven’t figured out what to do yet, but a fat and long rudder did help, forcing the boat offwind…

Currently i am working on making templates wich i will scan and share if anyone wants to experiment with such a boat (:

Good work, Spade. KARO was developed in the true spirit of Footys…to get an idea and build it! It sounds like you have a good idea about it’s strengths and weaknesses, so I suggest you sail it some more, figure out what you think would improve reaching performance, and build another. Then you can give one to a friend, and you’ll have a race :slight_smile:

Have fun…Bill

Thanks Bill!
So the second boat is allready build, with a 350g ballast and 515g total weight. The reason for the second boat so quickly is that i have to get my father sailing on a Karo becouse Spade footys, I raced at sestriere last year are left in the wave by the new boat (= +it takes like 20min to build a hull :smiley:
I am exited to se how the two boats will perform, becouse they both run same rigs, hulls, everything, but different ballasts.

and here are the templates i am currently using, ofcourse they are far away from the final pdf plan… …but here they are:

The hull is to be build out of 3mm thick material.
The arrows on the bullkhead show where the bottom is, the plate beside it, is mounted on the waterline(arrows facing forward) and is used to support the fin, the reciever and battery shall be placed on it. Additional bulkhead can be mounted for help with allignment of rudder post, and pivot points…the fin shall be 21.5cm long in order for the boat to fit in the box with an approx. 14 x 2 cm bulb, if everything above deck(servos, controlhorns…)are max 1cm high. Rudder template is on it’s way(still testing different rudders).

It was testing time during the weekend, the new boat was put in the water, and performed superbly.
Tho i the difference between the two boats was not noticable by eye. But the 50 extra gram should have made a difference? Or not?
Anyway i got my head around, and found a solution to poor reaching handling…
…i build a new rig wich is taller, but carries the same amount of sail, and i think, a narrow sail puts the forces on the sail closer together and, the boat is more dynamic now, it likes going over the waves, and changes directon easily, it has the same effect as puting weights closer to the keel of the boat instead into it’s ends.

Nosediving “analysis” and videos follow :wink:

here is some footage in gusty conditions, with the c rigg, derived from spade, the oldfooty of mine.
I think that up wind performance is quite good, and downwind also(but i have no real reference)… …the handling is suberb,now it has a rudder wich is longer, and fatter.