I was looking around in previous posts and the archives, but didn’t see anything on this subject. What fin set-up do you prefer, tri or single ?? Reasons why… Pros and cons ?? More speed, less speed ?? More drag, less drag ?? More bite, less bite ?? Is the 2+1 set-up the best of both worlds ??
sombody said one god, one country, one fin,…how bout one wife…personal preference … single fin all the way limit variables…simplify…rule of thumb on flat bottoms over 12" multi fin ,contour bottom diffrent story,running a single fin? 8" or over depth…dont forget flex as a factor it can be benificial…if you are in the neighborhood stop by lets look at the subject…ambrose…aloha from wipouli
As you make rail fins bigger and bigger, you get more drive, and more drag. Where you like the trade-off is up to you. In either case, fin positioning is pretty key. There are plenty of archived discussions on fin position to dig into.
I choose a single with more drive than a 3 fin system. 
3 fins forever…
na only joking…
it depends on how the board is set up …if its a rockered 8’ with the widest point pulled back and good outline ,then yea its gonna perform so a 3 fin will compliment it…like a big guys performance board…
on the other hand if its flat looking and straighter paralel out line ,then a single would work in it there,but also a thruster ,like a real small guys longboard…
ive got a class performance 8’ longboard has like 8-1/2 nose rocker and 2-3/4 tail ,perfect for those days when its 2 to 5 foot but soft ,the extra length and width means your all over everything that moves and the rocker keeps it free for still going vert and tighter turns…nothing else but a thruster would suit that board…its also sick on real crowded days in shortboard conditions ,you can sit out further and rack em up …i got another 8’ real flat wide point forward with a raked single ,its like the perfect hangover board ,i absolutly hate it except when im in total cruise mode and just wanna be out there …
regards
BERT