Al discusses the recent advancements in Multi-fin waveboard set ups from the crew at K4 Fins with the new Graham Ezzy signature - Asymmetrical Model. We have demo sets in the store - pop in and give them a go!
"K4 started off with flexier fins designed for multi fin waveboards and for the last few months they have been offering asymmetrical side fins for quad and thruster set ups developed with Graham Ezzy. Here is an article with Steve and Graham Ezzy talking about the development process. Read it here.
I’ve been playing around with them since the start of the year and the findings have been very interesting.
I’ve nicked Steve Thorp’s (the man behind K4) explanation:
'For many years all surfboards have been supplied with asymmetric front fins, windsurfing has only just caught on, perhaps in some part due to the extra complication for manufacturers and customers (I'll make this as painless as possible!).
By creating an asymmetric foil you can increase the amount of lift generated whilst keeping the drag low, the same as an aircraft wing. Asymmetric foils are more efficient at creating lift. This means more drive, power, hold and grip when your board is turning without a drag penalty.
Where things become complicated, is that an asymmetric foil will create lift when running 'straight', ie. it will pull to one side. This 'pull' is undesired for several reasons, but mostly that it is causing drag. In order to prevent this we turn the fin in towards the nose of the board until the fin neither pulls one way nor the other. This angle is the 'toe in'. Of course the amount of 'toe in' for no lift (least drag) in a straight line varies depending on board design and how fast you're travelling!'
If you don’t know what toe in is – there is a brief explanation here.
Surfboard fins have had toe in for ever. As far I’m aware in windsurfing the JP quads had it last year, Fanatic are now marketing it on their quads, the Nude/Starboard have used it on their twin fin set ups and Simmer have also been doing it for a while.
It was only a matter of time until we started putting a bit more tech into wavesailing fins. Surf fins are offered in multiple constructions/materials, foils and outlines. I know when I go surfing I have a few sets and chuck in what ever is most suitable for the conditions. Sooo many people underestimate the difference fins make to boards!
At first glance compared to the symmetrical shark tooth fins – the Ezzys had a wider base, swept back outline – basically with overall more area.
I normally run an 8cm front, 13cm rear quad set up so played around with the 8cm 1 degree and 2 degree sides. My first impressions where ‘initially it felt a little stiffer and less 'whippy' but after a few waves I got used to them and they
seemed to give more torque back up the wave face, making it easier to go vertical. I think the stubby outline having the extra area was why they felt a bit stiffer rather than the foil/toe, as I used them more it felt like I could really put more power into turns and also they gripped in coming back down from critical smack into air turns whereas my normal set up might not have had the grip to make it.
For straight line I didn't really notice any real loss of early planing or increase of drag and it seemed like they felt more solid underfoot and really cranked upwind. After a while I swapped to the 2 degrees and instantly noticed they felt draggier. On the wave it felt as though the extra torque was gone and I actually lost speed driving back up the face.’ A few other guys also tried them out in their JPs and basically found the same thing.
Basically for my current boards I’ve settled on the 1 degree set up for all conditions, small waves, mushy onshore or when it is firing clean down the line. Turning is more of a power gouge feeling, than skatey, and they are fast and grippy. In a straight line they are probably even better than with the symmetrical fins, because of the improved upwind performance.
Recently in Mauritius I was able to try a whole heap of boards and fin set ups back to back. For the JP quads I still found the same thing, that the 2 degrees felt as though you were pushing too much water and didn’t really improve turning ability. (I think this is because of the V under the footstraps). In the new thruster though the 2 degrees were awesome, no loss in speed or upwind ability and turned a hell of a lot better than with the stock fins. Will have to measure the boxes, but I suspect the thruster boxes are straight, whereas the quads have close to 1 degree of toe.
Steve’s guideline to set up your fins.
'Most boards will perform best when the toe angle is between 2 and 3 degrees. The k4s come with a choice of +1 or +2 degrees added toe. Therefore a board which has straight boxes (zero toe) will need the +2 fins, and a board with 1 degree or more boxes will need the +1.
You can also tune your board with toe in to some degree; small wave surfboards can have over 3 degrees toe, this is to make turns easier and sharper and can do this as the top speed is less important. Big wave surfboards have less toe for more drive, higher speeds and wider turns. You still need to stay within a reasonable range of toe though, so as not to cause unnecessary drag.'
To measure the fin set up in your board
'Difference in span between the ends of your front boxes in ‘mm’ and the angle of toe your boxes have (taking a 10cm box length)
DIFF 0, TOE 0 DIFF 1.75, TOE 0.5 DIFF 3.5, TOE 1.0 DIFF 5.25, TOE 1.5 DIFF 7.5, TOE 2.0'
Here is a guideline of boards we have measured and the recommended fins taking into account a turning bias. For a balance of speed and increased turning power over symmetrical fins choose slightly less toe.
JP Quad 2012 82, zero toe. Requires +2
JP Quad 2012 92, zero toe. Requires +2
JP Quad 2013, 0.9 degrees, requires +1 – based off my experience
JP Thruster 2012 92, zero toe. Requires +2
JP Thruster 2013 99, zero toe. Requires +2
JP Thruster 2014 73, 0.6 degrees. Requires +2
Tabou Pocket 2012 (Thruster) 80 – zero toe. Requires +2.
Tabou Pocket 2013 (Thruster) 85 – zero toe. Requires +2.
Fanatic 93 Quad, 2011, 1 degree. (+1 for speed bias, +2 for turn bias)
Quatro 76 KT, close to zero toe. Requires +2.
Simmer Fly 2012, 1.3 degrees, requires +1.
Starboard quad 2012, 1.7 degrees, requires +1.
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