Originally Posted by jyasaki
Wouldn't that be true in either case?
Not really - the floor drain could be inches away from the transom - a trunk needs to be flush with the floor.
I maybe wasn't too clear with my original explanation?
Originally Posted by captnjack
Then use a hole saw from the inside out so the bottom of the new hole aligns with the floor (and doesn't gouge the floor)
That was kind of what I was on about - a "standard" one where each saw is it;s own "can" you can do that - but some are like a big cast thing with multiple grooves into which you put the size of blade you need - then you have to do the final cut from the outside as there is likely going to be half an inch of excess blade carrier to foul the floor.
I get the feeling this is one of these "pic speaks 1000 words" moments!