: Don't want to make a hatch
: then find out that it is were the bulkhead goes.

Work out where your bulkhead will go first - even if only roughly.
If, like me, you don't want footrests and intend to put your feet
firmly on a glass-reinforced-plywood bulkhead, the position is
fairly critical, but the hatch position isn't - it can be a few inches
forward of conflicting with the bulkhead, which also makes reaching
into the bow a bit easier. The only restriction is that the further
forward it goes, the narrower it gets.

For the aft hatch, you probably want to consider whether you will
have a deck load (like split paddles or a deck bag to carry flares,
food, spare clothes or whatever more accessible than inside the boat)
and whether you mind if the deck load has to be removed to get into
the hatch. One possibility that no-one has mentioned is putting your
aft hatch *in* the bulkhead - if you have worked up an attractive
deck stripping pattern you may prefer not to spoil it with a hatch
and its associated retaining straps, bungees or whatever. Depending
on how much of an aft cockpit recess you have made, and how much
you intend to slope the aft bulkhead to make cockpit drainage easier
during rescues, you may have somewhere between not enough room and
plenty of space for a bulkhead hatch. I used an 8" round "inspection
cover" (also sold as "deck plate" etc.) in the aft bulkhead of my
hybrid cormorant, with a fairly low-cut aft recess and already a small
boat (built 94.5% of design size). I had to be a bit brutal trimming down
the rim, but it would have been easy on a design-sized boat. I am finding
this to be a really good solution - though I have a tiny (4") hatch right
aft (intended to give access to the skeg control), to make it easier to
push things down the hull within reach of the main access.

Andy