How to measure offshore limit for Bareboat Skipper IYT?

There is a limit for International Bareboat Skipper: In coastal waters up to 20 miles offshore (IYT page).

But what is the right way to measure it: from continent or nearest coast (island)? In my opinion it should be 20 miles from land with proper harbor or marina, but I have not found clarification of this rule.

Best Answer

It also says "in coastal waters." I would take this to mean that sailing from small islands in the ocean is not covered. As for where to measure the 20 miles from, it's from the shore, not from the marina.