Author Topic: Extra-Large Quad Fins for Wind-SUP  (Read 2374 times)

rhorton1

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Extra-Large Quad Fins for Wind-SUP
« on: February 28, 2017, 02:44:08 PM »
Hi All,

Long time lurker and first time poster! I am in the final stages of planning a wind-SUP build. A 9'6" innegra/carbon board with bamboo veneer reinforcements over 1.5lb stringerless EPS. All vacuum bagged. The overall shape will be something similar to a SupSports Hammer or Starboard Wide Point. The board will have a pretty fast/flat rocker so I can get it planing under wind-power. I want a step down from my Exocet 11'8" wind-SUP so I can do a little more light-wind wave sailing. It will also be used as a regular paddle-powered SUP.

I would like to put a quad-fin setup on the board and have a question about fin size. I have a windsurf-specific set of quad fins. 10cm + 16cm. They use longboard boxes. I also have a set of 13cm fins. Looking around at surf-specific fins, the XL size quad fin sets top out at about 11cm long. My question for you is would my XXL windsurf fins be beneficial for a wind-SUP build? My thought is that my being heavy at 200lb, plus the extra forces from a windsurf sail would necessitate the larger fins. I ask because the winsurf fins need different fin boxes than surf-style quad fins. Does anyone see a benefit to my adding some 8" longboard fin boxes in a quad-fin setup for this board?

I have used Pro-Box fin inserts in my surfboard and kiteboard builds, and have been very happy with the results. If the longboard boxes are not a good idea I will go back to Pro-Boxes and just grab the largest quad-fin set I can find.

laszlo

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Re: Extra-Large Quad Fins for Wind-SUP
« Reply #1 on: February 28, 2017, 03:25:42 PM »
I had a custom 8'10 Widepoint board made for me by Art Colyer at North Pacific Surfboards, (he built the original "Widepoint" boards for Wardog). I designed it specifically for windsup, as well as regular paddle surfing. It has 5 fin slots and I use it as a quad for SUS. I found that for windsup I have to use it in single fin mode. Even if the quad fins were larger, and the surfing fins are definitely not large enough, the angle at which the quad fin boxes are placed causes them to create drag, slowing down the board under sail. The board is designed to have a flatter rocker under the straps, and will actually plane when powered up, but only in single fin mode. Windsurf boards that are designed as quads undoubtedly have a different placement of the fin boxes, but I don't know how that would work when surfing without the sail.
« Last Edit: February 28, 2017, 03:30:22 PM by laszlo »

SUP Sports ®

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Re: Extra-Large Quad Fins for Wind-SUP
« Reply #2 on: February 28, 2017, 03:45:08 PM »
Aloha rhorton1,
Sounds like a fun build...welcome to the forum...

It's really all personal preference...and, optimizing the fin setup(s) to local conditions...etc...

I'll preface this by saying that I've been designing fins for a couple of decades...and, I have wave sailed multi-finned sailboards for decades...twins, tris, & quads...also, a longtime surfer, windsurfer, & paddlesurfer with 12 years of windSUP experience...etc...and, on my 8'5" and 8'11" Hammer windSUPs, I pretty much just sail them single fin...no problemo with AOA or, staying to weather...

https://youtu.be/eY0CVCSmKYY

I surf them with quad + small 2.25" StubNub...so, my recommendation would be to install a center box with your sidebiter box preference (mine is Futures) with normal cant/toe-in for surfing...

http://blog.surfingsports.com/?s=windsup

http://supsports.com/sup-fins/

It's all about max versatility...so, I even dropped a deep Tuttle box in my 8'5" Hammer for windfoiling and SUPfoiling...YMMV...

« Last Edit: February 28, 2017, 03:50:52 PM by SUPsports »
Mahalos...{:~)

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Dwight (DW)

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Re: Extra-Large Quad Fins for Wind-SUP
« Reply #3 on: March 01, 2017, 04:20:46 AM »
You want to preserve every ounce of planing efficiency, so single fin for sailing. Pop some side bites in when switching to SUP surfing.

So I'd do Chinook box in rear and Futures or ProBox side bites, toe and cant for surfing.

rhorton1

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Re: Extra-Large Quad Fins for Wind-SUP
« Reply #4 on: March 01, 2017, 08:10:12 AM »
Thank you all for the informed replies!

Wardog and DW - following your posts had a major part in inspiring me to tackle a wind-SUP build on my own. Good to hear from the masters! I'll follow your lead and put in a windsrf-rated longboard finbox in the board for single-fin sailing.

Hoping to get this build done in 1-2 month.... Will post some pictures when its finished!

 


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