can anyone explain how the centerboatd control lines are routed on 3386 as shown in this image. Rather than the winder system the board looks to have only one up and one down purchase, rather than purchases on each side. If this is the case - when you pull either up or down - i cant see where the fixed end of the purchase might be. Any clues?

No idea, but at one time the OK solution was:

From top of board forward to a pulley, from there out at 45 degrees or so to the side deck (within helm reach). Around a pulley and straight across the boat at the back of the foredeck / front of the cockpit. Around another pulley on the deck and straight inboard again. Around a pulley on the centreline and forward to the top of the board.

This gave a straight pull with no purchases, but a slightly off-balance feel and look.

They then moved to a triangle, duplicated on both sides of the boat: Top of board forward to a pulley. Out at 45 degrees to the helm position. Around a pulley and inboard to the centre line. Around another pulley and forward to the top of the board.

Things to look out for:
 - As well as moving the board, you are dragging the ropes on the other side of the boat around with you: this adds LOTS of friction to the system.
 - If you try to adjust the board while the crew is sitting on the leeward adjustable controls, the friction is so great that nothing moves until the crew does :-)

The system on 3386 was one that I had on various Solos and Phantom. One rope for up, one for down. The four dead ends are terminated at the thwart with elastic take ups for the slack. The uphaul went through an eye in the thwart (knot on the reverse to stop it going through), then inboard to the case, along the side and then up through the case top, round the block lashed to the board head, then down the other side. The downlaul is the reverse. To raise the board, a pull on the uphaul first takes up the slack against the elastic until the unpulled side runs to its stop. It is a bit agricultural and only gives a 2:1 purchase. The system on BAU and the Winders is a 4:1 both ways and is easier to move, although with twice the string to pull.

Hope that makes sense.