This is a great article by Paul Davis from NSW Central Coast in Free Sail in the early 90s.
I've always struggled with pumping short boards, while long boards have been fine. I wonder given my weight over 110kg whether it works better on a short board to set the boom high and concentrate on deweighting the board. Pumping seems to unsettle the board and stop me putting weight on the sail. Yes a few pumps but mostly concertrating on hanging out off the sail. (please dont tell me I wrong unless you too are over 110kg, and windsurfing in marginal conditions with big sails. I know very well it works for to 60 to 95kg range)
However with foils recently pumping really works for me, so I can now see what all the noise was about.

So I dragged this article out and then thought to share it.
I have some others more focused on short boards if there is interest, but this one is by far the most comprehensive.