How To Install A Hatch Ring On A Foredeck

Hi all, I wanted to hear from the group regarding how to install a hatch ring on the foredeck of my boat. The hatch is a Freeman 2400 series with an aluminum hatch ring on an aluminum boat. The foredeck has 1/4" camber in the spot where the ring will be installed. How would you install the ring so it will be perfectly level for welding? Any pictures would be greatly appreciated.

Bob

 

That hatch isn't going to be over anything you want to keep dry, is it? Lots of grease helps but the things are very prone to leaking if less than perfect maintenance, then there is the issue of the water that is in the crack on the compression seal model and the miniscule trough on the knife edge model (better than none), which needs to be drained... these hatches are usualy used on lazarettes.
If you do use it, It's non-locking, as well, I don't know the best welding technique but I will say they can take a little bend with no adverse effects. The rubber just compresses more in the middle than the sides, but 1/4" is a lot (too much).
You know, if you're not hammering it with fishing gear, or whatnot, I recommend a raised lip hatch of some type - and with hinges so that you don't have to control it when opened from below.