Tell me I'm not crazy

[dabigkahuna]

What's the biggest sail you've used (or know of) with a SUP?  I got a SuperFreak 8.0 to use with my Avanti (11'2" x 36" x 230 l) in small waves, but so far I'm using it mostly on flat water and I'm feeling pretty under powered in the light San Diego winds.  I think 8.0 is about the max I can use with my 12.5" fin so I'd probably need a bigger fin also.

Incidentally, I tried sailing without the side biters and only with the 12.5" true ames.  That didn't work.  I went sideways 2 feet for every foot I moved forward.   

[SUP Sports ®]

Aloha Paul,
The 8.0m2 SF is plenty big...as you suspect, you need to counter-balance that much sail area with more fin area...
Exactly why I designed and built the 10" and 12" FreeWeeds...they are low aspect, so the area is spread out horizontally to act like a keel increasing lateral resistance...

I have a couple of the 12" versions in SUPer stiff G-10, with US base, that will definitely help to solve your problem...

http://surfingsports.com/wardog_fin_designs.asp

http://blog.surfingsports.com/tag/bamboo-sup-fins

[nuernbergsup]

Hi,

I use a 9,5m Lefebvre Race Pro on my Mistral Allround 9'9 SUP. It is a dedicated raceboard sail, very light. I sail mostly on lakes.

Biggest problem is the US-fin box, you can not use a fin bigger than around 14'' without the danger that the box breaks.

[dabigkahuna]

... Biggest problem is the US-fin box, you can not use a fin bigger than around 14'' without the danger that the box breaks.

That's what I'm finding.  Biggest I've found is a 15" slalom fin.  The 12.5" True Ames slalom fin seems to work fine with my SuperFreak 8.0 as long as I have the side biter in.  Today I'm going to try moving the side biters to the "spare" fin boxes about 1/3 up the board.  Those boxes don't appear to be toed in so may not cause as much drag (I hope).  It's supposed to be a bit windier today (15 mph gusting 20) so should be a good day for a test.

[SUP Sports ®]

It's not the depth of the fin that's important here...it's surface area and how it is distributed...
A high aspect slalom fin will washout under too much load or too high AOA (angle of attack)...a keel type fin like my 10" or 12" FreeWeed will offer more lateral resistance spread out horizontally...and, closer to the hull to reduce drag...

At the end of the day...there is only so much you can do with the Starboard Avanti...a board with more waterline and flatter rocker will far eclipse it's hyrodynamic efficiency under sail...or, paddle power for that matter...

Sure you can try to improve it's performance...but, you rapidly reach a point of diminishing return...installing the best fin(s) in the world on it is still like just putting lipstick on a pig...;-)

[dabigkahuna]

... Sure you can try to improve it's performance...but, you rapidly reach a point of diminishing return...installing the best fin(s) in the world on it is still like just putting lipstick on a pig...;-)

Very true.  Since I've started to windsurf a ton, I just picked up a dedicated lightwind windsurfer.  WindSUP-ing the Avanti is fun, but as WarDay says, at some point of your main object is windsurfing and planing, a real windsurfer is the way to go.

[PonoBill]

I have a 9.0 Superfreak that I've used a few times. It's a lotta sail, but in light wind with the sail trimmed tight back (leech on the deck) it's plenty fun. I use a big ass true ames on my 12'2", couldn't say what's on the JL 11'7".

[dabigkahuna]

I've got an older SuperFreak 8.0 and I've come to appreciate its "soft" nature.  Having not windsurfed for a decade and a half, it's nice how "gentle" they are when coming round from a gybe or in gusts and wind shifts.  I've not used mine in the surf yet, but I imagine that's where they shine most.