We all know that if you are surfing a 2+1 and you move the centre fin back and forwards it makes the board looser or stiffer.
Is there a limit to how far you can move the centre fin forward without it negatively affecting the 2+1 set up? Does the water flow get messier if you put the centre fin right up level with the side bites?
Just try it.
Better yet, use a system to be able to change the position by hand on the water between each wave.
Either a FCSII connect fin, or a finjak.
www.seabreeze.com.au/forums/Stand-Up-Paddle/SUP/Quobba-Fins-?page=7#2683476
And of course, use Quobba fins :-)
Hi folks..yes I can try it but wondered if anyone has any technical advice on whether or not it affects water flow etc. I'm sure I read somewhere the fins can start working against each other. My usual go to is centre fin 2 inches behind trailing edge of side bites. If waves are a bit sized I put the centre back a bit.
Select to expand quoteSlab said..
Hi folks..yes I can try it but wondered if anyone has any technical advice on whether or not it affects water flow etc. I'm sure I read somewhere the fins can start working against each other.
Sidebites are inefficient and add a lot of drag.
With many fins, only one fin is in its proper water lines, the rest add drag.
The water exiting the rear of the board is never at the same angle on all fins, it depends on the wave and speed.
Just remove the sidebites and use your board as a single fin, you will be surprised by the gain in efficiency.
Multiple fins have advantages, especially for providing hold at high angles of the board when rolling on the side. But they have drawbacks (drag, stiffness). The game is to have the advantages overcome the drawbacks, and it depends on your technique, your riding style, your waves, your board...
I personally have always had my rear fin leading edge approximately 1/2 -1-1/4 from the trailing edge (tips) of front fins,and never have surfed a board with back fin forward of front trailing edge(tips).Why? I don't know! Technically!Other than like all surfers I have tried many fin combo's and my personal preference are the measurements above,that have been consistent over the entire time of multi finned boards mid seventies onwards,and currently sups,very personal stuff, as it has been suggested try it 
Slab,Just reread your post you referred to will the water flow get messier,IMO if it does you will feel it,and adjust accordingly,back to Micks very technical answer of TRY IT and let us know how it goes
Select to expand quotejustaddwater said..
Slab,Just reread your post you referred to will the water flow get messier,IMO if it does you will feel it,and adjust accordingly,back to Micks very technical answer of TRY IT and let us know how it goes
Yeah my pref has been around 2 inches from the front fins...actually never seen anyone with fins further forward or level.probs for a good reason. I just wondered if there was any technical water dynamics experts on the group 
