MB, I would disagree with your assessment. Sea kayaks are very capable, although I wouldn’t want to be out in rough weather in one, but then any boat would be bad. The principles of stealth are still required in the same way. If you are seen or heard on the water you will probably be caught. A coastal watcher can see for ten miles in daylight. If someone wanted to block traffic along the coast a boat stationed every couple of miles out to sea would find most boats day or night. If you go off shore in a larger boat, when daylight comes you would be totally visible from the water and air.