There is a lot written about bonzers… containment of the water via the concaves and the side fins, increasing drive and speed, allowing shorter wider boards (which turn more easily). For me, all theory aside, the crux of the matter is bonzers just “feel” better.
When I used to ride thrusters I was often plagued by poor foot positioning, (my excuses ranged from 7mm booties and numb feet, to onshore winds and bumpy take-offs)… and I used to frequently miss that narrow sweet spot that each board seemed to have. When I jumped on my first bonzer it just felt natural, the sweet spot seemed huge and pretty much I could ride it from anywhere on the board. And then there was the speed, particularly through roundhouses, and drive to spare. i was making it round sections I wouldn’t of, my off the tops came round quicker, and my take offs improved (due to extra foam and less rocker getting me in quicker). All of these components are a tribute to Malcolm Campbell and his original designs.
Whilst subtly (and radically) different, my boards are based on the theories tested and proven by MC and Duncan over decades. Every board I make carries the "peace sign" in acknowledgment of their designs and philosophies.
Glassers hate them, sanders loathe them, polishers despair… and they cost heaps more to make (time and money).
So for me, why bonzers? Well, they just feel better… and that’s what surfing is all about for most of us. 
Nigel Semmens - Malcolm Campbell - Bonzer Light Vehicle Russ Short - Guy Penwarden. Autumn 2009
