My adaptive paddling fixture for sit-on-top kayaking is (aguably) the most successful design created to date, being reproduced by univerities, inclusive recreational and physical therapy providers, and other such organizations across the United States and around the world.
Those unfamiliar with the capabilities of many adventurous outdoorsmen (and women) facing serious disabilities, may be surprised to hear that this fixture is designed to assist quadriplegics who have limited use of their arms and possibly little, if any, ability to grip with their hands. This fixture also proves especially useful for a paddler that has good use of only one arm and hand!
I put all my designs in the public domain so they can be freely reproduced, even for profit, and noone may patent them to preclude others from fabricating them and perpetuating their use.
Together with my seat adaption, shown in the photos below (and the subject of a future Instructable), this combination has safely brought the freedom, adventure, and inclusion of the wonderful sport of kayaking to hundreds of participants.
The Paddling Fixture is easily constructed with a minimum of parts and a total cost well under $100. The hardest part of the design process is making a few 90-degree bends in the aluminum braces that hold the base of the boom to the deck plate.
The design, as presented in this Instructable, is specifically tailored for use on an Ocean Kayak, Inc. Malibu Two model. The M2 is, to date, the best selling kayak in the world and the model most often found to be available at rental outfitters. This design is Plug & Play to a stock Malibu Two, requiring absolutely no modifications or additions to the kayak.
Modifications to this design for adaption to another kayak model may include one or both of: Changing the Base Plate (white, in the first photo below) in shape and/or method of attachment to the kayak, or changing the length of the Boom (shown as 48 inches in length in this design). The rest of the design would remain unchanged.
The List of Materials is quite small, so I'll simply present them as they are encountered in the build process. With that said, let's get started...
Step 1: BASE PLATE
The design of the Base Plate, as shown, allows for its fastening to a stock Ocean Kayak, Inc. Malibu Two kayak without any modifications or additions whatsoever to the kayak. This means that a rental kayak could be used to provide an awesome day out on the water for the paddler. Slight modifications to this design should allow it to be adapted to just about any sit-on-top kayak. Later, I'll present some alternative designs for other kayaks as well as decked (sit-inside) kayaks.
From a roughly 33 inch by 27 inch piece of plywood, 1/2 to 3/4 inches thick, mark and cut the pattern as depicted in the first drawing below.
For the Malibu Two, the critical dimensions are: (1) 16 inches wide where the front deck strap fits into the forward area of the Deck Plate, (2) 29 1/2 inches length between the center of the strap features and the hole where a large tie-wrap secures the rear-most features of the Deck Plate to the kayak, (3) 22 inches between the holes that get tie-wrapped to the factory placed eyelets on the M2, and (4) 23 max inches from the strap to the rear edge of the main part of the Deck Plate ensures the entire footwell area of the cockpit remains open. Simply mark these critical dimensions onto the wood or pattern first, then fill in the rest approximately as shown.
It is helpful to draw one side (left or right) of the pattern on a large sheet of paper and fold the paper along the center-line. Then cut out the pattern for a perfectly symmetrical design.
The CAD drawing below shows that several sets of holes are pre-drilled into the Deck Plate to facilitate adjustable longitudinal placement of the Boom Brackets. This will be discussed further later on.
Note that the first photo shows an earlier Boom and Boom Bracket design that incorporated a few extra parts. The adaption presented in this Instructable presents the latest design using the fewest possible parts.