Thanks CB & Benny, I've heard the saying so many times "That's a bit of clinker" etc to describe something subpar but never knew what a clinker was....just that it wasn't something great.
P.s a clinker built boat down here in Oz is one where the hull boards are overlapped, different to a carvel built boat where the hull boards are flush.
Say Jim, please let me speak to your boat building use of the work clinker, and let me say that like so much in the English language, that is the same word but of a very different derivation.
A clinker-built boat is more formally referred to as a Lapstrake boat, but the key to the use of the word "clinker" is that it is a corruption of the word "clincher", as when building lapstrake planking the planks overlap each other and are pulled tight together with clincher type fasteners, which are a bit like a cross between a nail and a rivet.
Hope that makes any sense, but there really is no significant correlation between the two different usages for the same word.