Looking good so far Tryhard. Agree with others about painting.
One error though. How are you going to attach the seat over the top of the frame with that bar attached to the mast post in the way? Get rid of that.
The mast post does not need that for support if the welding is good. Add a small gusset at the base of the mast post if you are worried about the weld.

The only time I have primed over a zinc base is if I'm going for a very light coloured gloss top coat.

Most yellows, light colours, particularly white and also some of the fluro colours need a white base to get the most out of the top gloss.
The zinc seems to make it very dull as it seems to absorb the pigment and takes many coats to cover. It then darkens the colour up.
I think the thinners out of the top coat soften the base zinc coat as it's porous and they blend a bit.

If it's a darker top gloss coat I never bother.

Here's a down and dirty look at the mistake.What I should have done is checked the assembly when everything was tacked.Now the job of dismantling is bigger

Getting the geometry right in the front can be tricky It looks as though yours can be easily fixed by cutting the welds at the forks/u bracket and re welding them on angled down more
Wattyl Kilrust paint is what I use on these things from Mitre10 Primer undercoat and topcoat in one hit durable stuff too
Impressed with your build so far I have used ski axles twice on minis and like them but I have reservations on using them angled back as I don't know how they will resist the twisting loads If they twist then the alignment will alter and make for an interesting ride especially if you are a big guy
It. should be noted that Clem is a featherweight so it might not apply to him

I did a rough experiment today by clamping two sections of skis face to face to my workbench with an overhang of 400 mm and put a load on the end offset to the centreline at 150mm
The overhang axle length at 400 mm is shorter than shown on the drawing which is about 600mm The offset of 150mm is close to what is shown on the drawing axle centre to tyre centre With a load applied [my right foot in a loop of rope]
The skis deflected down as expected but crucially twisted at least 10 degrees with at a guess 40 to 50 kgs load
My guess is if the yacht lifts a wheel the wheel on the ground is going to toe out maybe half the angle of twist due to the axle being at 45 degrees to the centreline
Am I right or am I missing something here ? The load on that wheel could well be 100kg in that situation and the twist would be greater than what I saw on my bench as the axle is longer as well
This is a lot of guess work on my part maybe someone can figure it out better than I but it seems to me the
centreline of the axle needs to meet the verticle centreline of the wheel to keep the rear wheels aligned

I weigh 90 kgs. Do I need 3 skis for my axle?

Hiko, Have you taken into consideration that the twisting force acting of the skis is not a simple vertical force but at an an angle to the skis as while in motion there is also a side force acting on the windward wheel trying to make it toe in. Perhaps we need to test our theories on the beach.
Yes think you may need 3 skis at 90 kgs as I am only 60kg.

I'll try 2 skis. Next questions:
1.what size is the boom?
2.Why are there 2 blocks for the mainsheet?

A trick for "softer" braid - washing in fabric softener makes it extra flexible, great for most sheets. Used to do it to all my abseiling and climbing ropes.

the front end welded up again.Here's a tip.Getting the parts right for welding is much easier than cutting through welds

But I discovered a very curious thing.This arm of the axle is 20mm shorter than the other even though the rig is square.Am I missing something here?

And yes I think he is correct,The styley socks were a stocking filler.I'll cut a bit off

Does it matter if one leg of the axle is a bit shorter than the other provided the axles themselves line up and the rest of the assembly is square?

I dithered over the shorter axle issue until I remembered seeing an earlier posting of Clems where he tested his rig for toe in under load.So I set up something similar to test for square etc

I cut a bit off the pedal support to push the assembly back and recycled the button clips from the windsurfer boom.These are the kind which you push down and slide to the next hole