Tribal Knowledge: Is anyone looking for SUP board design and or shaping tips?

[kingdavid]

Aloha,

Is anyone looking for help with SUP board design, shaping, materials, construction methods, tools and so forth? I would love to address any questions. I have built all types of boards for nearly 40 years using every type of construction method. This includes hand shaping through 3D CAD and CNC machining. Shoot me you questions and let's have a dialogue. I'd love to exchange tribal knowledge.

Best regards,

Dave Daum
King's Paddle Sports, Inc.
www.dave@kings-paddle-sports.com
www.kings-paddle-sports.com
760-822-7344
 

[Ronan "Doc Jacobs"]

Hi Dave

Here in France we don't have easy access to distance standup paddleboards, so I'm planning to have one shaped by my local shaper.
Do you have any idea of where I could find templates for a 14' board for overall conditions(I mean not only a downwinder). May I find a free software to help me in the design?
Thanx for your answers
Ronan

[Admin]

May I find a free software to help me in the design?

The free downloads of the outstanding AKU Shaper and Shape 3D software are available:

http://www.aps3000.com/download

http://www.shape3d.com/try-buy.htm

[Allan Cheateaux]

Ive got 2 14'ers that I shaped, so I can help you out with what I think worked on them and what didnt... I might still have the APS files as a place to start.



Thats a solid offer Dave. Big ups to you.

[Ronan "Doc Jacobs"]

Allan

Thanx for your offer, I will gladly take all the information you have, and of course an APS file. It seems you explored the subject, and maybe I'll avoid some BIG mistakes. I was planning to inspire myself from a 14' speed kayak hull, with canoe nose and tail, 27 or 28" wide, a small amount of nose and tail rocker.
Let me know, if you have time, about all your discoveries. Do you have pictures of your 14' beauties?
Ronan

[kingdavid]

Hello guys,

I've received many questions about the best design for distance paddle / race boards. In fact, I recently received a call form an angry individual in Lake Tahoe who complained because a buddy of his raced past him on one of our 10' surf-style SUP boards. What angered him was the fact he had just spent $4,000.00+ (US dollars) for a 14' carbon-fiber flat water race SUP only to be smoked by a guy on a surfboard. Here are some observations I've made:

1. Pointed outlines don't necessarily correlate with high speed; they simply cut through wind and chop better. Other things are more important than outline.
2. Keeping the rails very thin and pinched as opposed to thick and boxy makes a huge impact on how much drag is placed on the rails. Remember water follows curved surfaces; the less curve the less water drag.
3. Pinched rails make for less free-board allowing chop to splash over the deck vs. slapping against the rails.
4. Wet sanding the bottom and rails with 320 grit adds as much as 10% to 20% more hull speed.
5. Keeping the foil forward of center is faster.
6. A very gentle slope in the entry rocker blended back from the nose 2/3rds of the length of the board reduces water pushing.
7. 4" to 4 1/2" of nose rocker and 3 1/2" of tail rocker seems to work well.
8. We run a full V through the entire length of the board. We've found flat bottoms are slow and round bottoms have a maximum hull speed that, while consistent, may not be the fastest thing going.
9. We cut a concave in the center of the vee from nose back 2/3rds of the board length.
10. We cut deep double concaves in the back 1/3rd; blending them into the front concave and off the tail.
11. Keeping the wide point 2" ahead of center and converging with the thickest part of the board works well.
12. Thickness for 160lb. rider about 4" for 200lb. rider 4 1/4"
13. Keeping the center of gravity as low as possible by cutting into the deck or making the board thin is important.

Disclaimer: I pride myself in making boards that ride waves really well. I'm not a flat water expert per say. It is only through trial and error and feedback from customers that I've made these observations. The theoretically correct way to design a flat water racer is to take several iterations of our best designs, model them three dimensionally in a CAD program, run the CAD model through a computational fluid dynamics program, CNC machine the board, glass it and then go test the bloody thing. How may of us have the resources to do this? Even if we do (which I do) some knuckle-head on a handmade surfboard may still beat us.

All of this is my opinion and may run counter to the opinion of others. Forgive me if this is the case. The point is to begin sharing our gifts with each other. Let me know your thoughts so that our tribal knowledge may grow.

Best regards,

Dave Daum
mailto:dave@kings-paddle-sports.com

[Dwight (DW)]

WOW this thread is a dream come true for me. I'm about to start on my 14 ft garage made race boards. I have to make 2 of them. One for the wife too. 

I'm preparing to order enough foam for 3 boards. The first one being a throw away, if it turns into a dog.

Allan, I'd love a copy of your APS file. My email should be shown in the left pane.

Some question for David, or anyone who wants to join in 

5) Keeping the foil forward of center is faster What does that mean? When does a rail shape become a foil?

7. 4" to 4 1/2" of nose rocker and 3 1/2" of tail rocker seems to work well. Have you tested flatter rockers? I ask, because being an old windsurfer, I know their race boards have very flat rockers. Flat was considered fast. Some were near dead flat.

8. We run a full V through the entire length of the board. We've found flat bottoms are slow and round bottoms have a maximum hull speed that, while consistent, may not be the fastest thing going. I like your thinking with that idea. The original light wind Mistral One Design race board had slight vee its entire length. Like a crossover shape between displacement and planing.

13. Keeping the center of gravity as low as possible by cutting into the deck or making the board thin is important. I'm stoked to read you made your boards that thin. I was less stable on the C4 Vortice BW model, than my own little SUP simply because it was too thick. I was thinking about bucking the trend to go thick and go 4.25 myself.

Any thoughts how deep to go on concaves? On windsurfers, deeper limited top end, but their speeds are way higher.

My plan is go 1.0 lb EPS with 2 layers 6 oz top and bottom. Spackle the blank. Was going to bag it, but now getting cold feet on that part. All subject to change 

[Tom]

Dave, thanks for the offer, I've got a general design question for you. The other day while I was on my SUP, I traded with someone on a Skip Frye double eagle so he could try out SUPing. Since then I keep wondering how a Frye like Sup would work. Any thoughts?

[kingdavid]

Hi DW,

What I mean by foil is: looking at the side of the board, you see the rocker from tip to tail. In this same view you will see the thickness distributed from tip to tail. Have a look at the attached file showing some of my surf SUP rocker / foils and this may make more sense.

Flat rockers are generally faster. For flat water nose rocker is needed only to clear chop and to keep the nose above water. The tail rocker is needed to turn. Surfing rockers are a whole other can of worms.

I concur totally with you on the subject of V!

As far as CG and thickness go... Everyone is making their boards too thick. I have 220lb. guys on 3.75" thick boards who fly through the water. I weigh in at 165lbs. and ride 3.625" thick boards in all lengths. Many of our customers are shocked when they get off their thick boards and onto one of our thin SUP's. The just can't believe that a board with half the displacement can be so stable, fast and maneuverable.

As far as the depth of the concave is concerned; a little goes a long way. A 3/8" deep concave should be more than enough. For flat water the concave only works if it is cut in a V bottom and it's maximum width is 12" to 18" at the widest point. The concave shouldn't go all the way out to the rail. It must stop approximately, 6" to 8" short of the rail.

By the way, anyone visiting San Diego is welcome to stop by my shaping room at any time. I'd love to show and tell in real time. Also, May 17th and 18th the Sacred Craft Show will be at the Ventura Fair Grounds. It is a wonderful showcase for handcrafted boards. King's Paddle Sports will have a booth at the show. Please stop by and say hello. During this show I'll be shaping boards and narrating the entire process. Come by and watch.

Best regards,

Dave

[kingdavid]

Hi Tom,

Your experience with the Skippy board confirms everything we have be covering in this thread. Skip is the master of flow. His boards are super fast due to flat rocker, belly and V that run all the way through the board. His super thin rails draw very little water and are fast. Skip is so amazing. I'm sure that Skip could make a fantastic SUP if he put his mind to it.

Although Skip's boards are not my style, they are amazing. Skip is one of the greatest shapers of all time.

Dave

[Dwight (DW)]

The talk about vee being fast reminded me of something.

The very first SUP race held here (Southeastern NC) was won by a stock Surftech Takayama SUP. It beat the only race board in the fleet.

I think the Takayama is known for having vee for much of its length. 

[kingdavid]

DW,

You are very observant. Donald Takayama, like his mentor Hap Jacobs, is known for running Vee all the way from tip to tail.

The guy on the stock Surftech must have either been a super strong paddler; had very little competition; or had a board that moved through the water really well. This must have pissed off the dedicated flat water paddle board crowd???

Anyway, lets take what we are learning and apply it.

[CHill]

Dave, Have a question on fins. I own and race the board DW posted about Surftech Munoz Ultra Glide 12' and during training have changed fins out and around for stability and speed one of the things I noticed was a single was not as fast as a twin fin, the single wanted to yaw after a couple strokes and the twin didnt the single seemed a lot tipper and the twin fin also took care of this. The twins are MR fins also tried different size singles and placements in the box with the twins still being the better ones, any merit to this and should race boards have the ability to change up fins for personal prefrence and conditions? Thanks Chris   

[PonoBill]

To expand on that fin question, I'v'e found that low aspect fins seem faster than high aspect ones on standard length boards. Not a lot of science to that conclusion, just GPS measurements on a lake, but the difference seemed big enough to be worthwhile. Any thoughts.

[Dwight (DW)]

Anyone know a source for high density foam blocks to set my fin box in?

All I can find are thin sheets.

I thought it would be easy to find, but not so.

Coming from a windsurf background, the thought of setting a box in EPS without it, doesn't fly.

I'm even going to use a Chinook windsurf box. Way stronger than a longboard box in my opinion.