OS,
I had a familiar scenario on my 1980 C30. The strut they used was too long to bolt to the hull bottom. So in their great wisdom(?), they past the strut down from inside thru a slot. Then, simply mudded in the baseplate to secure it & act as a seal.
Well this worked fine until one bottom job haulout. When I picked up my newly bottomed boat, I loaded her up & set out for a weekender with my girlfriend. Waiting to fall asleep, I heard my bilge pump running. Upon checking, the water was coming in from you guessed it, under the fuel tank. I discovered that using the lift's straps, they were positioned wrong. They picked up my boat with one strap on the shaft, not the hull. I was not there for this. Back at the yard & mad, there was a mark on the shaft paint the width of the strap. On all of my future haul outs, I place duct tape on my toerail to mark the CORRECT strap locations & I am there for the haulout & splash.
Removing the fuel tank was easy & sure enough, the mudding was cracked & water was coming in. If you've been to a yard recently & have the same type install, chances may be that they lifted her wrong. The fix was easy but, I will never again let a yard lift it incorrectly.
My pump was pretty quiet, that's why I didn't notice it. I installed a panel so if my pump is on, so is the indicator light.
Call Catalina @ 727.544.6681. Ask for Warren, he can tell you what type install you have.
There was also a Cali. number: 818.884.7700. I always spoke with Kent in engineering.
As an added bonus, here's a pic of the lift point & block-up locations for my boat. I would think you would be the same but, ask them to send you this for your boat.
Hope this helps pal........
CR
