I used a scope to see under the grid and there is 1 to 1.5" gap from the bottom of the post to the top of the keel. The only way to get to it is to cut a opening in the grid just aft of the post, faceing forward.
When it fills with water, the bilge pump won't pump it out , It's in the grid. Holds about 2-2.5gals. befor it gets to the bilge pump.
Not sure about cutting in to the grid?