There are several ways to install hatches. First, you need to figure what you need it for. Access to a valve, or simply an inspection
port can be handled with a large hole-saw or jig saw, cutting a circle, then dropping in a plastic "inspection plate". If you don't know what's under the spot you need the hole, you must take a gamble, which can be very risky. Improve your chances by tapping on the floorboards to see if you can determine where there are crossbeams or athwartship frames. If you cant tell, then try to find one of the small tv camera
units with a flexible wand. It's a handy piece of boat gear
which you will find very useful over the years.
Once you feel confident you aren't cutting out something structural, then begin worrying about what the idiots who assembled the boat decided to snake under the floorboard, such as critical electronic cables
, electrical wiring
, etc. In other words, don't just cut a hole and hope things will be okay.
Having confirmed you have nothing to worry about, and that the location of the access hole is correct, then you need only consider the cosmetics of the finished product, and how you are going to keep the hatch
in place when the world is bouncing around you. Screwing it in is always a secure idea. Or, spend some money
on a fancier latching device. Spend good money
on this unit since bilge water
plays hell with chrome-plated zinc-magnesium (ZEE-Mag) hardware
. You can build some supporting ledgers all around the perimeter of the opening, glued and screwed for strength.
On my boat, I just made all the floorboards removable to provide complete access to my bilges. Mine use rectangular aluminum
"tubing" with honeycomb soles to keep the weight down, but originally, I built them out of plywood
The attached photos show a hole I had to install in a Catalina fiberglass
to allow some electronic cables
to go somewhere. First I inserted a camera
to check out the substrate. I'm glad I did. The other pics are of the new floorboards of aluminum
stringers and honeycomb/epoxy, with nonskid paint