After posting the same question on a private sea kayak instructors' group, and on a forum at paddling.com, there is strong consensus that it is going to be extremely difficult to teach self-rescues with sit-inside, recreational kayaks.

While the lack of proper perimeter lines does play a part in making a paddle-float self-rescue more difficult, the large volume of water that fills a sit-inside, recreational kayak after a capsize is by far the dominant factor making even an assisted rescue very difficult, and self-rescue virtually impossible.

Most sit-inside, recreational kayaks have very large cockpits, making them easy to get in and out of. They are also very wide, making them very stable in flat water. They also have very little buoyancy (floatation) in their bows, just lots of extra open space (and I see no benefit other than it saves the manufacturer money and allows them to sell more cheaply). Those things combine to allow huge amounts of water to flood the boat after a capsize. The boat then becomes unmanageable or "unemptyable".

In contrast, sea (or touring) kayaks generally have much lower cockpit volumes and have bow bulkheads and storage compartments – making the boat more buoyant and easier to empty. (However, read the warnings about even sea kayak cockpit volumes being too large and requiring extra buoyancy: Over...and Still Out?)

Also in contrast are the sit-on-tops (SOTs) which are recreational kayaks that are inherently buoyant, self-draining boats and relatively easy to re-board from deep water.

Best advice to teachers: don't try to teach self-rescues in sit-inside recreational kayaks, unless by way of example on how difficult/impossible it is with such boats.

Best advice to paddlers of sit-inside recreational kayaks: stay in calm waters, stay close (swimming distance) to the shore, and stay with other paddlers.

After posting the same question on a private sea kayak instructors' group, and on a forum at paddling.com, there is strong consensus that it is going to be extremely difficult to teach self-rescues with sit-inside, recreational kayaks.

While the lack of proper perimeter lines does play a part in making a paddle-float self-rescue more difficult, the large volume of water that fills a sit-inside, recreational kayak after a capsize is by far the dominant factor making even an assisted rescue very difficult, and self-rescue virtually impossible.

Most sit-inside, recreational kayaks have very large cockpits, making them easy to get in and out of. They are also very wide, making them very stable in flat water. They also have very little buoyancy (floatation) in their bows, just lots of extra open space (and I see no benefit other than it saves the manufacturer money and allows them to sell more cheaply). Those things combine to allow huge amounts of water to flood the boat after a capsize. The boat then becomes unmanageable or "unemptyable".

In contrast, sea (or touring) kayaks generally have much lower cockpit volumes and have bow bulkheads and storage compartments – making the boat more buoyant and easier to empty. (However, read the warnings about even sea kayak cockpit volumes being too large and requiring extra buoyancy: Over...and Still Out?)

Also in contrast are the sit-on-tops (SOTs) which are recreational kayaks that are inherently buoyant, self-draining boats and relatively easy to re-board from deep water.

Best advice to teachers: don't try to teach self-rescues in sit-inside recreational kayaks, unless by way of example on how difficult/impossible it is with such boats.

Best advice to paddlers of sit-inside recreational kayaks: stay in calm waters, stay close (swimming distance) to the shore, and stay with other paddlers.