proto footy update

The unarigg was moved 2cm forward, now the boat has better helm balance at bigger angles of heel, and is stable while nosediving downwind.
The 200g ballast is a good choice for this hull. but a 250g bullb will be introduced, because bigger riggs(more than 1500cm2) will also be used on this boat.
I also tried it with the 350g bulb of of a KARo, but that was too much, the boat didn't want to heel, and with no grip from the chine leeway increased. Responsivnes was also compromised.
Today the wind went from 2-3 knots to some 7-8, A+ to A rigg conditions.

Autum is in full swing, later the wind blew the leaves away, luckly

The light conditions were just to demanding for my Iphone today

downwind is now stable, this boat does lose more speed than a KARO does when nosediving

reaching is good, even when overpowered.

More conclusions will be drawn when i get a chance to sail against a KARO, or other footys..
here are a couple clips:

and with the 350g bulb:

new footy prototype

Yesterday a new design went waterbourne,

It is a fat design, made out of 4 3mm depron panels for easy building.
It is placed longitudinaly and nose down into the box, 153mm wide at stern and has a 32cm lwl.
The bulb is 200g, total weight is 380g. The updated KARo a rigg is used.

The goal for this boat was to create a light weight(sub400g) boat, which is beamy, with lots of volume, so it can go over the waves(no through them like KARo does), i decided to go for the 4 panels so i can modify the hull quickly, and so that some one will decide to build it cause it is a 4h project if u already have a rigg.
templates follow.

It goes quite good already. I will shift the rigg forward tho for a more neutral helm when heeled(the 12% lead of CE to CLR is not enough, there is some weather helm, too much for my liking. The hull is very stable obviously(lots of volume is shifted forward so the entrance angle is quite bad but that doesn't seem to affect speed.
Upwind the chine bites, and the boat is shaky over the little waves, i don't like that..  ..but it seems faster upwind than a karo. Downwind it has a problem..     ..it is so light that it gets thrown over it's bow and onto its side, it takes too long to get to the old course again..   ..a possible solution to that is a longer rudder. But when not heavily overpowered it goes well.

Tomorrow it will be in the water again with the changes. There are also some leaks that have to be fixed.
After i am happy with the balance upwind and downwind is solved this proto will be taken apart for templates.

clip

Duck footy

Today it was time to finally take out the Duck, a footy designed by G. Sanderson, as far as i know only three hulls were made. There is little data available on the net, but the boat was featured in this article: http://footy.rcsailing.net/articles/my152/footy_design.php
Mr. Sanderson sent me some basic measurments so i could complete the hull, which he sent me almost a year ago, after we met in Sestriere at the 2012 footy gold cup.

The rudder is made like suggested by the photos, her designer sent me, the finn is a 10% chord thicknes helicopter blade

the keel box is 1cm longer than the finn so it's position can be adjusted, the hole in the deck accomodates my 4x8cm servo module, and acts as a hatch

Two balljoints hold the rudder, and a piece of brass tubing secures it with friction

Here is the boat with the karo a rigg

The boat has it's LCB shifted far forward, which makes the waterline round at bow and slim at stern(sort of fish shaped), such volume distribution trimms the boat under heel in a very special way. The stern actualy drops, and the attack angle of the finns icreases with heel and that reduces leeway, succes of such Wl shape was proved this year with Phil Tylers SLiM design.

I didn't do any calculations on this model, so i was unsure of it's balance, but right away it became obvious that upwind balance was bang on!

But nothing is perfect, when nosedivng downwind control was lost at times, because of the rudder which is to short.

Eventually the rigg was changed to the new a rigg with 1500cm2

The CE is recessed some 10mm compared to the original rigg, but that didn't seem to affect the upwind balance.

Clip 1

clip2

Overall i am very pleased with the boat, it seems to be fast in all directions. The wegiht is 360g + rigg(40gmax), which is quite light. Ballast is 200grams.
It will be used for speed and angle comaprison along side with my KAROs for future footy projects.
If interest for footys rises here in Slowenia it will be at the front end of the footy fleet for sure!

Thanks to Mr. Gary Sanderson for giving me the chance to finish one of his hulls!

Karo, rigg evolution

After returning from the footy goldcup i was super inspired, went straight to work, improving the Karo.
(I will write my report on the race as soon as i can catch my father for the photos)

In france i realized that the next step in my footy development will be a new type of rigg.
My unariggs had some drawbacks, which became visible on the race course, sailing against other boats and in "crowdy" conditions.

The first was that my higher aspect ratios did not carry as much sail as competitors with two sails, they produce the same speed, but don't accelerate the boat as quickly as a classic rigg does.
The centre of effort is higher, so the single high sail provides quite a lot of heel.

The second thing was they were to stiff, sort of hammering the boat when not under power, and loosing speed through tacks, so a softer material has to be found

The third thing was the damn backstay, i got caught numerous times while sailing at the front of the fleet or at start.

On the way back I went through the sketches i had made for the classic rigg.

Today the rigg was finished, it has funny geometry, sporting a Stollery mainsail, and a 450cm2 jib, with a combined area of 1400cm2.

The mainsail is made of icarex, kite material. For now the jib is kimoto foil(it is to stiff)
The main thing is no backstay, i am sure that the chance of getting tangeld with the shrouds is way smaller, on this rigg they provide forestay tension.

The main benefit is probably lowering the CE for 12cm.  

The jib was provisorically attached, so i could take the boat for a spin, a removable swivel will be introduced so jibs can be raplaced easily.
Todays impression was superb, i managed to put the overall CE about 2cm further behind than with the unarigg. The boat sails way more responsively than before, and nosediving seems to be reduced.
For the first try the performance is very satisfying.
Tomorrow i plan on taking both Karos to the pond, and hopefully finding someone to sail one of them for comparison.
Clips follow.


The plans for this rigg:
1. Make a 1800cm2 version
2. Make a 1000cm2 version
3. Compare on water performance to the unariggs
4. try:  moving mast aft & changing sailarea ratios(bigger % jib),  getting lift from the jib


I will put down my thoughts about the new hull design in another post.

Footy B-rigg

Yesterday the B-rigg was finished.
It has about 1080 sqcms of sail, and an aspect ratio of 2.1.
at the moment it works fine, the boat points well and gets up to max speed quickly when sailing upwind, tacks are super fast(becouse of the big rudder) but yet controlable. Downwind it was just a matter of reducing sail area. It needs no backstay as the mast is a hobbyking 4mm carbontube, it has  super thin walls, so it bends under gusts depowering the sail.
On this rigg no ballast on the boom is needed and the total weight of the rigg is 33g.

Here are a few pictures from the pond, when i find the time i'll post some better ones

Gold cup Karo hits the water & rigg details

Today i verified the performance of the new boat. arrived at the pond to find it was full of people fishing and their fishing lines. I moved to the only free spot on the shore, and started sailing. the wind was somewhat gusty with 10-15knots of speed, the water was teribbly choppy. But the boat seems to perform well, despite the missing bowbumper. soon it started to make water due to a porosion hole in the bow, but that was a quick fix.
Anyway here are some crappy phone pictures:

here are some pictures of the 1260cm2 a rigg, wich is good for winds up to 15knots, and makes a really nice shape.

the karo project is still ongoing!
things to do:
-finish the "body work", yellow paint
-build a boat for myself(this one will be skippered by my father)
-build and test the b rigg(a+ and c are allready done and running fine)
-build some more hulls so i can offer them to anyone interested