Your observation is correct! Bulkhead C in the plans is opened out a lot more with a much wider opening to the forecabin. I've two reasons for leaving it smaller (at least for now):
(a) I can't decide how wide to make it until the forecabin is actually completed. If it is really inconvenient to get in/out of, I'll make it wider.
(b) We won't use that cabin to sleep in - it might fit one adult, or two children. But would be a mighty tight squeeze for two average-sized adults. So I will leave the opening narrow initially. It will provide added stiffness and strength to the mast-step and deck above, in lieu of a compression post. Plus, if we ever need any spare wood in emergencies we can always cut it out of that piece I did also have it in the back of my mind to be able to seal off that cabin in case there was a major leak in the front portion of the boat, but I think that if such a thing happened, it would be a pretty muich unrecoverable situation.
Anyway, a month to think over lots of boat stuff, when I'm not building.
First though, a flight to a little closer to your boat in a couple of days. Arrive in Paris on Wednesday - a week there, then a week in the south, with some other European cities afterwards. Really looking forward to it all. I was 11 years old last time in Paris...and a lot of time has passed since then!
Cheers,
Mick