Fabricating a hatch cover from existing bow decking

[LongWinded]

O.K, One step at a time here.
I picked up this 'free' 12' fiberglass sailboat that I want to transform into a duck hunting boat.
My first task is to fabricate a removable/lockable hatch cover from the existing bow decking.
I think what I want to do is cut out a sizable peice of decking roughly 30"x "36 opening, as wide as the cockpit and about 12" short of the bow.
Then reinforcing hatch cover strong enough for a man to walk accross it.

To make the cover fit into the deck I was considering installing some type of channel around all edges of the cover that would fit into a similar channel installed around the edges of the intact decking. If that made any sense.
What parts or materials are available for a project such as this? And what installation method? Aluminum??
Any better ideas out there?
How should I reinforce the hatch cover?

The third picture has been edited into this thread several days after I originally posted this. It is a veiw forward through the bulkhead to bow exposing reinforced ribs below the bow decking.
Below, on each side are the exterior walls of the hull.
I think I may cut-out the deck 1/4" out from the perimeter of the two diagonal ribs to fabricate the hatch cover from.
Then glass-in a wall beneath the gunnel to the floor and fill with foam for flotation and rigidity on each side.
Install aluminum I-Beam say 1" wide beneath the gunnel, from the bow to the bulkhead with a 1/4" exposed for the hatch cover to rest on.
Add vinyl edging around gunnel's and perimeter of hatch cover with say one sided 1/4"adhesive foam tape on top of exposed I-Beam all to create a seal.

I think I know what I want but really have limited knowledge on how to get there or what materials to use.
Any input is appreciated.

[LongWinded]

The long narrow raised strip down the center of the bow decking is a rigid channel, which I feel is strong enough to support the weight of a man.

How should I reinforce the edges of the hatch cover from deflecting in from excess weight?

I might try fastening aluminum plate underneath the deck perimeter that extends out 1/4" the hatch lid to set on.
To fasten this plate should I rivet it? Glass it in???

Really, any thoughts, ideas, or suggestions on the direction and construction technique I am taking this this project are welcome. As I really have no clue how to acheive the final results I want.
I am merely speaking my thoughts outloud in desperation for technical support and direction.

This is the first of many plans I have for this boat. And I'm sure when I finish I'll be ready for another.

[marshmat]

Well, to throw a bit of a wrench in your plans, that foredeck is structural. Not only is it meant to take the loads of the mast, it also provides the rigidity to stop the hullsides from flexing.
Since you don't need the mast anymore, that makes things a bit easier. But I don't think you'd be able to just cut a three-foot piece out, put it on hinges, and expect it to hold a person. You'd need to add stiffeners around the edges of the cutout for sure, and also on the section that will become the hatch panel. I'd do these in glass/epoxy. If you want to stand on it, either the stiffeners will be really beefy or you'll have to add braces across your new hole. There's probably foam up there too, which is needed for flotation when a wave comes into the cockpit. Have you thought about two smaller hatches, or do you have to fit a single big thing in there?
What would go in this compartment? If it's a duck gun or other long thin things, I'd sooner see the deck kept intact and the compartment be accessed via a hatch in the forward bulkhead of the cockpit. Again, though, any cutout will need some reinforcing.

[LongWinded]

Well today I was able to squeeze the camera lense past the forward bulkhead and this is what I saw.............
I am thinking about cutting out the bow decking for the removable hatch lid 1/4" outside the perimeter of the two side ribs, then glassing in an interior wall and filling with expanding foam for floatation and rigidity.