INTRODUCTION
"Scupper", per thefreedictionary.com, it is defined as 
1. Nautical - An opening in the side of a ship at deck level to allow water to run off.
2. An opening for draining off water, as from a floor or the roof of a building.
                  
In kayaking, scuppers drain water per the definition but also act as structure in the "Sit-on-top" versions. The floor of such a small water craft is just a few inches and sometimes less than an inch above the water line. Going out into breakers or conditions beyond, "glassy" can spout water up through these structural holes. While it drains out quickly, it proves noisy and messy. For this purpose, the scupper plug was born.
There are many entries in the kayak industry, this is one I designed for Legacy Paddlesports in 2012.

Starting with the mathematical basics... P=F/A (pressure=force per unit area). In other words, the smaller the surface area, the higher the sealing pressure. Notice the thin rings and it makes sense... Thin ribs will continue to seal in very sandy conditions because the land is so small that the grains are removed from the sealing edge during installation. The tapered ribs also make installation and removal easy while the hollow core allows the plug to conform to grossly misshapen features.
Other key features include the ergo grab handle which is designed to be easy to pull and comfortable to stand on, providing maximum standing area in the boat. If you want to add a tether, just poke a hole in the bottom of the plug and run your tether. The ribs inside provide extra durability and assist with plug removal by pulling the walls in and away from the sealing ribs.

DESIGNED IN THE USA!
INSPIRATION
Clockwise front top/left corner: 
1. Check valve scupper is a cool idea but stands proud in the boat. This limits standing room and creates a "trip" condition.
2. Expandable scupper. Old reliable method of sealing holes but it is an outdated tank of a part suffering from some of the same issues as the first plug.
3. Legacy's old generic scupper that this new design replaced. Simply put, its a chemistry plug.
4. A conical style plug designed by the competition. Its simple and low profile but doesn't seal well.
5. Another conical style plug lacking the low profile feature suffering from the same issues as other conical style plugs.
6. Inspiration for this design came from superior features of this design. While it's a good, low cost idea, it failed to meet our requirements for sand, intrusion into the foot area, redundant seal, super strong tether attachment and style.
SKETCHING OUT CONCEPTS
A few of the sketches. This design process actually went very quickly. Concept to prototypes was about 2 or 3 weeks.
MODELING THE PART
Different views in Solidworks.
PROTOTYPING
3D Printed rubber plugs
CHECKING THE FIT
Testing first production samples.
I shot this image to provide a clear visual of how the plug works.
TESTING
A beautiful morning paddle testing out first production samples.
Here is a quick video of the scuppers in action.
PRODUCTION
Finally! A whole bunch of production parts!
First production samples fitted into our Deuce Coupe model Kayak.
First production samples fitted into our Slayer 12 Fishing Kayak.
With the launch of the Native Watercraft Ultimate FX Series on 02.24.14, these scupper plugs now double as the industries largest drain plug!
 
See the boat models here:
ACKNOWLEDGMENTS
Special thanks to:
Shane Benedict, Sam Spear, Steve Harris, Kent and the Rotaloc Team.
Thanks to the whole Legacy Paddlesports team for your trust in me and letting me take control and push the limits on this scupper plug! You're all awesome!
Finally, thanks to my wife and kids for putting up with the long hours; I love you!
ABOUT THE INDUSTRY
 
Here are a couple links to learn about the industry these are used in, check out the competition, read the reviews and hopefully get sucked into this wonderful industry just like I did. Enjoy.
 
Scupper Plugs
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Scupper Plugs

This is a "Scupper Plug" I designed for Legacy Paddlesports. Check them out at www.nativewatercraft.com or www.liquidlogickayaks.com The design Read More

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