I am fitting a new toilet back into the boat where the old one was before, the holes don't line up though.
You can see from the photos that the old toilet somehow bolted to the level fibreglass lining. I am just unsure what type of bolt etc I should use to fasten the toilet base. I thought maybe a big self tapping bolt but I'm not sure the glass is thick enough, and I need to be careful that the bolt does not protrude into the hull ;)

Looks like a good solution. Keep a nice bead of sealant around the edges to make sure you dont get water in between the two surfaces

Just make sure the bolts protruding up at the new centers are secured from rotating as you tighten the nut on the top. Some epoxy in the hole should do the trick.

Just fill the old holes in with filler. Drill new holes to suit using 8g self tappers. Drill the pilot hole with plenty of clearance to the shank size of the screw.

Got a new electric head the other day. Space is limited and you don't wanna rest your head on your pillow and have a toilet bowl next to your face etc. So I'm contemplating placing the toilet on a track type arrangement. So it can be pulled out to be used and pushed back to store. The hoses will flex no prob. Sucks having a small boat. Anyone seen anything like this?