It happened first in Hatteras this spring, and like a dumb-ass, it took me a while to figure it out. I was struggling and struggling to stay upwind with a nice stock 18cm MFC Freestyle Pro UL that came with my Goya X1. At first I was chalking it up to my abilities, and no question that is undoubtedly part of it, but what was happening was that the fin was snagging the odd strand of sea grass. Not a huge wad, but just enough, maybe 5 or 10 strands to get the drag going so I was pushing hard to get and stay planing, and having a really hard time making ANY upwind progress. For a freestyler, that is a bitch - there are only so many tricks you can try before you know it, your beach house is way in the distance. I had no weed fin there in Hatteras with me, so I was stuck dealing with it.
Prior to our trip to Shippagan, I had read a comment somewhere about weeds and wanted to be prepared. I had also heard about the emergence of a new fin company out of Quebec, called Makani Fins. At first, I have to admit that I found the use of Hawaii'an names and graphics for a Canadian fin manufacturer a bit weird. Whatever... In the end, it's all about the product anyway!
I was keen to support an upstart Canadian company so I thought I would give their 18cm Nai'a fin (a weed-shaped Freestyle fin) a go for Shippagan. I bought a powerbox for my 2010 Goya X1 105. My sails are '10 Goya Eclipses (5.3 and 4.7) and Gurus (4.2 and 3.7). I got to ride the board/fin combo with the 5.3, 4.7 and 4.2 while there, in a variety of conditions, but most flat-water. When I sail, I basically try tricks on every tack, a variety of vulcans, spocks, 540's, grubbies and swayze attempts (yes, I will still call them swayzes, as I think Web Pedrick deserves the recognition for inventing this awesome & frustrating move - how did 'flaka' ever stick?).
The verdict: It was great! In what way? Well, two things mainly. First of all, the fin just worked well for all those sail sizes in all the conditions I sailed, from dead flat to chop. Second of all, and perhaps the biggest compliment, is that it never felt significantly different than any other non-weed freestyle fin I've used. Given that the MFC Freestyle Pro is probably as close as you can get to an industry standard (hard to say there is really a 'standard' since FS fins in general are so massively diverse in shape and size), I think that is a substantial accomplishment for Makani fins. I would say maybe, just maybe, I could have used a 16cm here and there (due to a bit of resistance to sliding backwards), but I was overall very pleased with the 18cm. Kudos to Makani Fins for producing a winner in my books!
Please note, I don't sail nearly enough to be considered remotely an expert on the subject matter, or even close. All I can say with confidence is the 18cm Nai'a fin clearly worked well for me, shed the weeds like it should (I never had ANY accumulate), and let me do my business without feeling any weirdness under the board. It's a great fin at a great price ($99). If you ever freestyle anywhere weedy, buy one!