There's nothing like lazy Sunday afternoons for this forum. I have been reading about the need for downhaul (lots of it) particularly for uncut windsurfer sails and especially the cammed ones.My Skiwi modelled after Clemco's Skimini has the mainsheet fixed about mid boom.Do I apply downhaul here or at the foot of the sail at the mast?

As a windsurfer I should put downhaul at the the foot of the sail at the mast. It's the only place where you can generate enough tension to get loose lease in the sail and the right curvature in the mast. Don't put too much tension on the boom neither.

At the foot Tryhard. The sail is probably already fitted with a fitting at that corner which will enable huge downhaul tension to an appropriate multiple pulley block.

Ours are setup like this. The masts are supported internally, but a regular mast step can be setup the same.
I aim for about 350-400 kilograms of total downhaul on uncut sails.

More info here.(towards the bottom of the page.) www.seabreeze.com.au/forums/Land-Yacht-Sailing/Construction/The-evolution-of-my-Lake-Lefroy-Minis/