I enjoy combining paddling and geocaching. The second cache in my 16 KM Allumette Lake (the Ottawa River) loop is about the size of a medium peanut butter jar made from a 3” ABS threaded plug and cap.
To ensure a good seal, Please add an 1/8 of a turn after finger tightening. Only hand tighten.
Kayaks and canoes only; the area is rocky.