I went to bunnings and considered doing the same thing as confused. But those shelving systems are pretty expensive, I think each of those brackets is like $15 each... and the rails are i think $50+ so being a bit of a cheap bastard I decided to DIY. Ended up being a fair bit cheaper, was just over $100 if I remember.
I bought some cheap timber and some really cheap 90 degree angles to screw it all together. Its all screwed into studs. I live in a rental but the real estate agent was fine with it as long as I took em down when I leave.
usually the bottom shelf holds all my sails+masts+boom. was originally gonna put some marine carpet or something over the arms, but seems pointless so haven't bothered.
I think having the boards horizontally carried probably gives the best utilisation of space. You can pack the boards in a lot tighter than I have if you take your fins out, but I'm too lazy for that.