Removing fuel sending unit that appears to have no screws or bolts

[dieseldork]

Greetings!
New boat owner here. I recently procured a 2000 Regal 2100LSR as an intro to boating. It had a few little issues, and I'm addressing them one at a time and have a blast doing so.
Currently one thing on my list that has me stumped is removal of the fuel sending unit. There to not appear to be any screws or bolts on the top of it. There are what appear to be 5 "studs" on the top where I would expect to find screws or bolts. I assume that MAYBE you twist the unit to remove it? Has anyone encountered such? I've been SEARCHING the forums, google, and parts catalogs for a couple weeks of weeks and have not seen anything like it. Everything seems to have bolts or screws. I don't want to further complicate the issue by damaging it or the tank whilst trying to get it out. Certainly, I'd rather know the correct removal process if someone can lend a hand.

I assume the unit is bad, as the gauge reads FULL at all times. If I remove the red lead, the gauge drops to EMPTY immediately.

Please reference the attached pic.

Thank you all! This has been an invaluable site for me!

 

[GA_Boater]

Welcome aboard.

The rivet appearing things have to be screws. If they aren't screws, the sending unit had to be riveted in place before the tank was assembled.

Pick/scrape on the heads to find the slot or cross. It looks like there are slotted screws under the red and black wires.

Who made the tank?

 

[Scott Danforth]

could be studs with another access panel somewhere to get to them. you may have to pull the tank

however if the tank is reading full all the time, disconnect the pink wire at both ends (gauge and sender). if the gauge still reads full, its the gauge

if it drops, check the wire for a short to ground.

if the wire isnt shorted to ground, then it may be the sender.

 

[legalfee]

If you have an ohm meter disconnect the wires and measure resistance. Empty is 240 ohms and full is 33 ohms.