If you didn't mark it before the deck went on, I'd drill a 1/4" hole in the deck about where you want the hatch, reach in with a bent clothes hanger and find the rib then cover the 1/4" hole with the hatch. SEEYA Jack

Yes....that could work!   Thanks.

I figured someone likely has the dimension on the two inner supports I am going between.   But if nobody does than your idea should work.

Appreciate it.

I installed my hatch last weekend.  Yes, drill the 1/4 and find the structures.  So that your jig saw does not scratch up the surface of your board cover it's base with two layers of masking tape.  I through bolted mine with number 6 flat head machine screws and nuts so that I could remove it for revarnishing.  I beded mine in "plumbers putty" so that I could easily remove it for revarnishing.  Plumbers putty on a boat!  Well, it does seal Your sink drain and is easy to clean up.  If you silicon it you could have a mess and it is not easy to remove for revarnishing.

Would an ultrasonic "stud finder" locate the supports?

Was also thinking of a stud finder and may try that!!   I already varnished as I was told to install this last.   So I think I will just silicone it in.   Nervouse about drilling a hole in a place I may not want it or can cover with the hatch.   May try the stud finder.....just surprised that a dimension could not be located that would show where those #2, #3, #4 supports are located?

My stringers spacing makes anywhere from 30-43 inches a good spot for the Hatch.

CLC manual says 39.25 to the center of hatch.

Mine is a late model Kit build so I dont know if this helps or not!

David

Thanks!   I didn't see anything mentioned about this in my manual?   I will have to look again.   Anyone install one recently that could measure for me??

I was worried this would happen to me, so in the back of the manual I wrote down the measurements so I wouldn't make a mistake. If you still havent' drilled, say something and I'll go take a look at what I write down. Even with that information, it was a leap of faith cutting into the board.

Chris

As per CLC center of my hatch is 35" from bow

Phil