Plug for Hobie Mirage propulsor slot

The Hobie Mirage is a sit-upon rotomolded plastic kayak that can be paddled or can be propelled using a novel pedaled propulsor that drops through a slot through the footwell of the boat. I prefer to lift the propulsor out of its slot whenever I switch to paddle while underway, but I do not enjoy being splashed by water spouting into the boat. I designed and built a foam plug that can be latched into the slot when the propulsor is removed while underway. See the boat in action at hobiecat.com website, search on "Mirage." This plug project was part of my user review of the boat, "Love is a Mirage," in the 01 August 2000 issue of MESSING ABOUT IN BOATS magazine. To see my related Instructables, including "Kayak Dolly" and "No-Pour Concrete Boat Ramp," click on "unclesam" just below the title above or in the INFO box to the right. On the new page that appears, repeatedly click "NEXT" to see all of them.
Unclesam

Step 1 Tools and materials

The propulsor slot shown from the bottom of the boat, one-foot ruler. The plug is made of RIGID plastic insulating foam from the smallest can available, the version that has the lowest amount of expansion. Plastic wrap serves as a mold release, corrugated cardboard is cut to establsh the sides and top of the plug that are above the level of the slot itself. A 6" length of 1/2" diameter aluminum rod takes the place of the propulser's axle, and the boat has latches that will hold the plug's rod in place. The ends of the aluminum rod are rounded over, and two 4" lengths of 1/8" (approx) diameter steel rod are put through two holes in the aluminum rod, one drilled 2" from each end of the aluminum rod. The area around each hole is swaged with a center punch to keep the small rods in place, and the ends of the small rods are bent in toward each other to conform to the shape of the slot. The finished plug is given two coats of latex exterior house paint.