Sailing at Safety Bay yesterday in about 18-20 knots.

6m sail,
107 Litre FSW board
28cm Weed fin
96kg

I was having trouble getting planing and when I was I could hardly go up wind at all.
(made much worse by the guy who could hardly kite going up staight up and down the middle of the pond)
I always seem to have problems at Saftey Bay pointing upwind unless it is really blowing.


Is my fin too small? I think the board came with a 31cm (non-weed fin) Is there a definitive conversion between weed and none weed fins?
Or am I just too fat and rubbish?
I have changed to a waist harness this year would this make much of a difference?