water tank input port?

[dbsea]

my C30 water tank has an unused input port. Looks like about half inch, but it's not punched out. How does one possibly punch it out in the right way, especially so that you don't lose the plastic piece in the tank? I intend to use this as input from my watermaker that I'm working on installing.

 

[Full_O_Fish]

If your tank is like mine, all of the tank ports are "spin welded" onto the tank with flanged fittings. These fittings get installed without putting any holes in the tank so the plug you see is likely the actual tank wall. My recommendation would be to drill it out using either a forstner or auger style bit and a strong shop vac to catch the debris. If you had a second vac you could take the outlet from it and tape it over the vent on the side of the hull to slightly pressurize the tank to help ensure debris only goes out and not in.

 

[nzfisher]

An old wood auger bit with a good center screw thread and sharp wings with a dulled scraper blade (the part that is the approximate radius of the bit) slightly warmed should hold scrap and not create many, if any chips. If chips does fall off, it should only be the one circular chip. Try a sample cut using a plastic carton for proof of concept.