Installing Tank Watch Monitor in new holding tank

[SV Demeter]

I replaced my holding tank with a new plastic tank and am considering reinstalling the tank watch monitor sending unit from my old tank as it is in fine shape. The sending unit install requires drilling a hole in the top of the tank and the sender is held in place with (4) screws and a rubber gasket. My old tank was stainless steel and the PO had installed what looked to be maybe weld nuts for the sender's screws to grip. The old tank was definitly custom so maybe the nuts were welded on during the fab process.

At any rate I have a nice new plastic tank now with all the fittings intalled in the top and I am very reluctant to go cutting a hole in this new tank. My guess would be to reinstall the sender using self tapping pan head screws, the rubber gasket, and some sealant or even dreaded 5200. Im not sure what would stick well to the tank and dont want this fitting to leak. Suggestions?

[GordMay]

Tapping screw & adhesive sealants won’t work on a plastic tank.

Instead, see the Tank Access Plate System

➥ Seabuilt - Access Plate Systems

➥ BargainBoatParts.com - Tank Access Plate System

[SV Demeter]

Thanks Gord. Holding out for a cheaper alternative plus I dont have room for a 6" hole in the top of my tank.