Thanks all. Just to be clear, I am considering options in the event of an engine fail, not planning a deliberate landing.
Here is a photo of an example, this is on a rising neap tide perhaps 2 hours after low water. In this situation I think the beach (with very soft sand here) is the only realistic option because the large area of very shallow reef would be lethal. With a higher tide, I think I would go for the water here. In other places there is deeper water off the beach and the surf would be an option.
