We tested with the mockup to see if you can actually stand in the sloping companionway and you can, quite easily, so it seems that a sliding hatch is not strictly needed. It may make you sit further forward in the cabin, but not much, as your head is narrower than you shoulders, if you see what I mean. It also means you have a nice sloping back support whilst lounging on deck reading a book and having a beer (the main point of sailing in my experience). What may be a problem is that if it rains, you could get more rain into the open cabin, but a spray hood should help solve that.
What is particularly nice about the construction method is that nothing is absolutely fixed until it is finished. When I saw Matt clamping bits of plywood into different positions to mock things up I asked if he just got it all in the right shape and then simply poured epoxy over it to fix it. I was slightly disconcerted when he said "Yup, that's about it."
