Abstract: A sit-on-top kayak hull having an elevated void in the area between the normal seated position of a paddlers legs. The elevated void which is formed into the hull of the watercraft and extends there-through to a height above the normal laden waterline generally to a level of the approximate height of the gunwales forms a hole in the craft which is surrounded by walls. Various modules may be inserted into the hull void for varying needs, such as storage modules, clear modules for underwater vision, or flotation modules. The hull void additionally allows for changes in the running surface of the kayak by insertion of rudders, skegs, centerboards or other devices The void may be left open in full or part for egress of scuba hoses, anchors or other marine devices without affecting the structural integrity of the kayak, its buoyancy, or adversely affecting its performance.

Abstract: A multi-part kayak whereby the kayak body is hollow and void of a center where a traditional sit-on-top kayak cockpit would reside. The kayak body thus having a centralized hole therethrough. Surrounded by the hollow perimeter body the design is best analogous to a doughnut with a hole in its center. The kayak perimeter body is designed to accommodate multiple central hulls which can additionally accept multiple cockpit configurations via insertion into the central hull. Additionally such arrangement provides removable central hulls to be affixed in a manner whereby no mechanical fasteners or points of possible water intrusion exist below the waterline. Means are provided so as to prevent occupants weight from forcing the removable central hull downward through the kayak body and from wave action forcing the removable central hull upward through the kayak body.