I have only built one Shearwater (the Double) so am not familiar with the order of operations in the build manual for the Sport Hybrid.  Before going hatchless, think through the process of deck installation.  Unless you are using shear clamps, you will need to access to tape the inside of the hull/deck seam.  If bulkheads are installed prior to the deck going on, then a hatch is needed to provide access.  The other route is to install bulkheads after the deck goes on, and access the inside through the cockpit which will be a bit of a reach to get to the bow.  The problem with that approach is installing the BHs after the deck is a bit of a pain.  If you do go hatchless, I'd recommend some kind of small Beckson type hatch in the front BH so you can vent the compartment when the boat is not in use.

If it were mine, I would install the hatches even if you rarely will use them.  They are there if needed and there are few negatives to installing them other than a little time and a little weight.  

Pictures are the SWD.  The manual calls for bulkheads to be installed prior to the deck.  The inside seams are then taped through the hatches.

   Its a hybrid...the deck is already on.

--travis

i have a shearwater regular and a hybrid night heron....and several full strip builds - the petrels and some others.

i put front and rear hatches in all my boats though i will freely admit i rarely use them.

having a lot of experience with kayaks as well as commercially built power and sailboats, i think it isgenerally a very bad idea to have an enclosed space without a hatch that allows you access/inspection.

inevitably, water finds its way into things and its best to be able to open hatches and ensure things are dry and, when put away, moisture free.  truly enclosed areas are a risk becuase of heat expansion and contraction which can distort a surface, and inevitably, if there was moisture in the air, under certain conditions, it can condense out forming water in a place that can do a lot of damage if not allowed to dry. 

also, if something breaks, a hatch becomes important in a lot of repairs.  so i would agree with Mark N, that if you did not want a traditional hatch, i would still do a beckson hatch and put a pin-hole in it to allow the hull to breath so it does not blow up in hot temps or collapse in cold.

for me, i like my hatches on the deck....becuase when i do want to use, them, though it is rare, they are there and convenient.   as to size of the hatches, i tend to go with the design proposal.  i find the small forward hatch very limiting when you do need to get stuff in there.....and what i try to fit in has just comes with experience....

i would simply say, that most of the time, when i do want to take something with me, i need to use the rear hatch to accomodate it.  for example, i have a relatively small  insulated lunch bag that i use that accomodates a small 8 inch by 3 inch by 1 inch freezer ice block, a sandwich and some little snacks and some water....that i use for lunches in the summer.  it won't fit in the front hatch.  but easily fits into the back hatch.   again, it doesn't seem that big, but it won't fit in the small hatch...

anyway, those are my thoughts and i hope they are helpful.

h

   @hspira - this makes the most sense to me..

"inevitably, water finds its way into things and its best to be able to open hatches and ensure things are dry and, when put away, moisture free.  truly enclosed areas are a risk becuase of heat expansion and contraction which can distort a surface, and inevitably, if there was moisture in the air, under certain conditions, it can condense out forming water in a place that can do a lot of damage if not allowed to dry. "

i will cut them in, thx for the reply.

--travis