You know what they say, "measure twice cut once". Well I measured several times but the end result was the same; I made what is colloquially known as a major "Cock Up"!
When I came to build the stem I made a series of paper patterns with the cross section at each 100mm station. You'll see them in the photo's of the stem below. What I managed to do somehow was draw the first one (the one at deck level) totally wrong. Instead of making the width at the stem face 72mm I made it 36mm, forgetting that the (36) on the plan related to the half width. That's why those pictures below show a nice inward curve towards the top end.
Never mind, I glued a couple of blocks of scrap wood back on, smothered in epoxy/wood flour mix and no one will ever know (if I hadn't come clean).
The offending item is now curing at the moment, ready for the finishing touches when everything has set. At the weekend I'll probably make a start on the scarfing of the side panels.