I've been mucking around with fin set up and my board it seems to track better with a 9" center fin and 2 thrusters.In theory 3 fins should hold the nose of the board straighter on the forward stroke (maybe it's how I paddle?). I know it will be a fraction slower, but don't you think the trade off would be worth it. The fastest way to get some where is in a straight line, even if you go a bit slower. Also if the board tracks better with 3 fins, but goes slower why not set the thrusters parallel with the center fin to eliminate drag. I think this would be a good set up for someone who wants a good all round board and not interested in pumping it for speed when surfing. I know most fin set ups have already been proven, but sometimes the simplest ideas are overlooked.
90 Mile
good idea to experiment, as everybody is different,
I found that removing the side fins altogether board speed(paddling)was much better.
paddle technique then comes into play and with improvement to keep board straight,
worth trying.
I've been using mine as a single fin lately but using a slightly bigger fin than the stock fin.
IMO on this board the side fins need to be angled in.
DJ
Select to expand quoteShireSUP said..
JP uses the side fins parallel seems to work - im happy 
Yes but they are a short board styled sup board.. I think doing this to a long board styled sup board [like the 10'6.5] would make it harder to turn.
DJ
I suppose it depends what you want to achieve, paddle speed, tracking or manoeuvrability.
What about using smaller side fins rather than removing them altogether?
Select to expand quoteDavidJohn said..ShireSUP said..
JP uses the side fins parallel seems to work - im happy
Yes but they are a short board styled sup board.. I think doing this to a long board styled sup board [like the 10'6.5] would make it harder to turn.
DJ
Style perhaps DJ but at 10'8 it makes the 10'6.5 look like its little cousin 
I don't think the side fins slow the board down too much, I'd be working on a good sized side fin set, and mucking around with the centre to find optimal. . tracking V on wave turning..
Select to expand quote90MileBeac said..why not set the thrusters parallel with the center fin to eliminate drag.
Because drag is reduced when the fins are in the direction of the water flow. And the water flow is not parallel to the center line... and the angle varies with speed. Thus, side fins being positioned for surfing speed, they will add drag for flatwater paddling. On the opposite, parallel fins will add drag when surfing.
Ideally, you would want specialized side fin boxes with a toe-in designed for flat water paddling, or boxes with adjustable toe-in. But it i simpler to just go single for flat water.
