The kayaks are only allowed around the ship and are not to be taken to shore. I think this is more of a safety issue than a time issue.
When you take the kayaks out, they tell you 1/2 hour max. If no one is sitting there waiting to go on one, you could go longer. We always thought this was a short time but after you go around the ship once, you are usually pretty tired.
Hope that answers your question.
