Looking at that second video it appears the whole machine may be made of timber about 3" x 2", super light and cheap with no welding required Spine is a simple one length and fixed to front axle without any need to resist twisting, rear axle pivots beneath the rider and attached to the foot/bar steering by push/pull rod. No reason why the sheet cannot be attached to above the seat as with lots of yachts or by centre boom with an appropriate boom. I suspect the hand-held sheet was of an initial trial to see if the whole idea works...and it does, well done. The wide front spaced wheels fit the reason the deadly single front wheel 3 wheeled motor bikes were banned and replaced by quads. One of the most simple and practical constructions for the home handyman in ages. As an after thought - extend the spine and fit a jib. Then you really do have a "land yacht"
Do you mean replace with a jib? Or do you mean add complication of two sheet ropes and steering = 3 hands
Adding a jib was just a suggestion but there is a clever way of rigging a self-tracking jib on a yacht. I'll see if I can find the photos of one of my yachts and post it. There are advantages in having a jib.
I have to confess that I have kept quiet during this thread, as I had already built (and crashed) a stern steerer 3 times before this thread had begun. 
Greg (with his dog below) had drawn a stern steerer on my welding bench with engineers chalk and every time I walked past it stared me in the eye. I weakened and built it the next weekend.
Even when "landyacht" visited me, I had to hide it in the bush behind my shed to keep it secret. Also thanks "sn" for keeping it close to your chest.
Greg was a huge help with the finer design parameters. 
"Cock tail" can now be revealed, as it was sailed at Lake Lefroy last weekend with good results. It didn't compete as it didn't for fill, the parameters of 5.6 mini. It was just a fun machine for those that had the balls to sail it.
Here is the date when it was first completed and I painted it. The testing/“crashing” took place the next few days.
The reason about the secrecy was I was still trying to sort it out and get it stable. Just to prove that it might be able to be done.
It was reassuring when I saw the video clips posted in the previous page.
The problem was the tests were done in light wind, on a wet boggy surface with a huge sail that just got me to the scene of the accident quicker. It lasted 11 minutes on the GPS before having to rebuild it the first time. The mast dug in when the wheel bogged and it wasn't pretty.
This is it in it’s original configuration and it was much too light on the rear wheel. Even with the adjustable axle position right forward under the forward seat position. Originally it had only 16kgs on the rear wheel and I weigh 110kgs.
It is pictured here with 8.4 mt2 of sail for the first test run. 
After the first crash it looked like it had been thumped on top of the mast and looked like a squashed spider. 
I wasn't hurt.
The chassis after the first crash.
After the 3rd rebuild. See the new seat position now. It is fitted here with a seat (off my yacht I raced last weekend) till I knew where to make the cut outs for the steering pedals on the stern steerer.
It doesn't fit the mini class as I originally wanted, due to making it more stable with a slightly bigger footprint for testing and my insurance.
I have sailed it in very high winds and managed 77.1 kmh with it.
I rebuilt it and I sailed it on the shire “side show area” of our local Agricultural Grounds in Esperance only to end up with tyres full of punctures due to all the thorns in the grassed area.
When rebuilt I made it all adjustable, which added much weight, but made it easy to adjust one item at a time to get the centre of effort correct. (I went down to a 5.7 mtr sail as well)
Everything is adjustable fore and aft to get it balanced.
There was a lot of guessing and head scratching but last weekend I was very happy with it. Just need to sail it in a gale now.
It is very sensitive to the steering but very controllable. The steering rod is well clear of the fibreglass seat so as all can be adjusted without it fouling when steering. The control arm on the rear wheel needs to be much longer to make the steering less sensitive.
The rear wheel has “forward” trail built into it, just like a Lake Lefroy Mini, as when steering inputs are made the wheel leans the correct way to take the load applied by the sail and resists sliding.
By doing this, I have proved that I can certainly have less weight on the rear wheel. Although when it is well over powered or to much wrong input given, it pirouettes beautifully. 
It has now been adjusted and further sailed by a few sailors that were game at Lefroy with good feedback except for the opposite steering inputs required.
I didn't have a problem, as it is like an aircraft "push right rudder" and it turns right. Where as Paul spat it and left it in the middle of the lake and walked back shouting,” to set it the right way round”. As a pilot of light aircraft, I found the steering second nature, and so did most of the test pilots over the weekend. 
Testing will continue and it’s been a fantastic project.
Thanks heaps for your design help and inputs Greg. 
Here is Ron taking it for a test run last weekend at Lake Lefroy West Australia. It's a 5.7 cambered sail. The lumps of salt on the lake by the mast were really unusual and very solid.
I love a challenge. 
Been heap of fun along the way too.
Awesome work Chook!!
I love it when someone chucks the rule book - and gets away with it.
the rooster tail is pretty good touch too
stephen
Thanks Stephen.
When Vic "AUS 230" helped me unload from my trailer at Lefroy, he thought it was tangled up with another yacht I had bought. Had him confused for a few seconds.
It had me stumped for a few seconds.I was very surprised when I took it for a sail(when I figured out the steering) I found it quite stable and got to thinking this thing could end up quite fast,lot of fun. Thanks Chook.
You were most welcome Vic.
Just about under way for the first time on Lefroy here.
nooooo,nooooo,noooooo,noooooo..........................................stupidity unleashed,stop tempting the plebs chook
Ha ha onya, Paul........
I think it comes down to the "eye of the beer holder".
If you ask "landyacht" right now, it wouldn't even make a positive score Gizmo.
At least it sailed when his didn't. It was very light wind in his defence.
When the wind was up more, I could point much higher than a blokart and round them up speed wise, while we were social sailing on the Thursday afternoon. In the light wind they ran rings round me due to my weight.
If I was honest Gizmo, "Cock tail" in it's present form.......... I'd say a 7.
It needs more kilometres under it's belt and high winds to see how close I have got to the "correct" Centre of Effort. It will certainly be more sensitive to differing pilot weights than a conventional craft.
It is a VERY strange feeling the first time you lift a front wheel at speed. It's very stable though and you can carry the wheel for some distance till the wind lulls again.
I'll run it through the summer on our Pink Lake here and I'll have a much better idea after that.
If nothing else it has certainly scratched the itch I had.
I went for a walk on our local Pink Lake in Esperance and it's almost sailable. Just a few sloshy spots. So more testing shortly.
The local surface is not as nice as the holy grail of all sailing surfaces Lake Lefroy West Australia.
In the meantime back to building.
Just a crazy thought Chook.
Looking at that photo above right hand front wheel is directly in line the base of the mast. Have you considered making it a Y frame?
A "REVERSE" Y-frame?
At least then the wheel wouldn't "toe-in" under load, like all the conventional ones I've seen.
I have often thought that the centreline of the axle should be directly over the tyre patch to avoid the change in wheel alignment on y configuration axles I don't recall seeing any yacht that has done this though
has anyone actually measured this change?
That is my point Hiko.
When the Y axle is compressed, the wheel toes-in a considerable amount. This is particularly noticeable on 26" wheels.
Just pick up the front of a yacht slightly and listen to the tyres scrubbing on concrete as you move it forward. It sounds awful.
It must have an effect on rolling resistance. I guess the bonus of the flex in the axle is the smoothness of the ride and less sail shake.
The only advantages I feel now with a Y frame is, to get the pilot CofG lower and a bit smoother ride.
The sail shake is a thing of the past.
With the "sail set up" Greg and I now use, there is no longer any such thing as sail shake.
It has been completely eliminated, under all sailing conditions.
"There is no such thing as sail shake". Don't hold back reveal to us sitting on the edge of our seats the cure to this pestilence
interesting thoughts on alignment. my finding is that on yachts that spend all thier time trying to control alignment i got lots of tyre wear.
with the Y just the right and the axles just the right length and just the right front flexand the chassis twist reduced by good chassis design the tyres hardly wear. remember tha flat lefroy is the exception , most locations are rougher. I suspect chooks advantage is the weekends failed class 5 marathon would have been his vertical wheels, but a couple of knots wind change would have ruined that
Yeh we are spoilt rotten with Lefroy's smooth surface. (We got onto Pink Lake this afternoon for the first time since winter and it was pretty soggy. Made us appreciate the sailing a few weekends before on Lefroy's hard salt.)
My reasoning was that the wheels working against each other "Toed-in" under some load must be detrimental to efficiency. I understand that the unloaded rear wheel wouldn't have as much influence on the increased friction/rolling resistance though.
Like all things, I guess it comes down to compromises. The whole world can't be wrong with all the beautifully built Y framed yachts that sail outstandingly well.Select to expand quotelandyacht said..
I suspect chooks advantage is the weekends failed class 5 marathon would have been his vertical wheels, but a couple of knots wind change would have ruined that
Yeh your right Paul. But in my defence, last year with the same 2 degree setup, we had 38knots of wind in the weekends Class 5 circuit racing and I won. Bit of pilot ballast helped.Select to expand quoteHiko said..
"There is no such thing as sail shake". Don't hold back reveal to us sitting on the edge of our seats the cure to this pestilence
Love your use of lingo (language) Hiko
In my mini's with huge downhaul tensions (450kgs plus) the mast tip is pulled so tight into a curve that there is no way the sail can shake. Even when the sheet rope is completely released at high speed travelling in any direction, the top (above the bottom 3 battens) of the sail simply weathervanes. It's still as tight as a drum and without a single wrinkle. This is how in 25 knots of wind I still can sail with a 8.4 mts2 sail.
It's totally controllable and the top half of the sail is only used for up and down wind legs.
The windsurfers worked this out many many years ago. Our idea is why try and reinvent the wheel. These sized windsurfer sails (in skilled hands) do over 50 knots on water.
Also none of the cambered "Severn" sails, I currently use for sailing have cost me more than $15.00 Australian dollars. (thanks "sn" and Rob from Brunswick Junction) They were saved from the tip. The carbon masts were as well at just $15.00 each. So it has been very inexpensive at $60 a sail size, to experiment with cambered sails.
All the necessary technical information is already printed on the sails and also the sail bag.
The sail size.
The mast to use. (How long and how strong in IMCS.) Just poke a 800mm length of 48mm x 4mm aluminium scaffolding tube up the base of the standard diameter mast "SDM". You may need to extend the tip to clear your head. (We stand the mast step up.)
How long your boom needs to be.
(some sails even have the wrinkle indicators above the 3 batten to set your downhaul pressure to, for different wind strengths.
All the science has already been nutted out for us to use them.
Everyone without exception that has sailed my mini yachts with these sails, comes back totally "blown away", by just how simple they are to control in high winds.
The fullness of the sail is only controlled by the downhaul.
The out haul on the clew is set "as hard as I can possibly tension it".
I hope this information helps other land sailors, to go out and give cambered sails a go.
Thanks for that chook I think I will give it a go on my LLf mini I need a bit more sail area anyway and if that setup will handle strong winds as well
Well it sounds great
A few people have tried cam sails on mini's and got pissed off trying to get the cambers onto the mast. 
Watch a video on YouTube to see how. (See from 2 min 30 how much downhaul is required.)
From 4min.45sec, how to clip them on and then more downhaul
