|Inexpensive water tight hatches and inspection ports.....
Instead of making a water tight hatches, or buying deck (inspection) ports, take a regular rubbermaid container, or 5 gallon bucket, cut the container down and just use the lip / lid sealed to a bulkhead.
Originally saw on the bionic log from Skip Johnson -- look at the 2002 conroe messabout pictures.
My favorite stuff for this job is "Marine Goop". Get at Home Depot, in small squeeze tube or the big caulking gun type.
No need to buy these containers....
I just picked up 2 of the 6 gallon buckets (12" diameter lids) and 4 of the 9? gallon buckets (15" lid) for FREE from a local pool cleaning company. They go thru tons of buckets of cleaning supplies and just throw them out.