Cannot find leak for the life of me

I have an older tandem oasis (one with bow hatch, and 3 circle hatches) ) that's been taking on gallons over 4-5hr trips in the ocean. I cannot find the damn leak for the life of me. I've tried my compressor and soapy water, I've dried the inside and shot it with the hose, esp around hatches, i have hosed the steering lines and handles, inspected scupper/seat holes, retightened hatches, checked/silicone greased orings (no rolling). Is there somewhere I missing??? It is a considerable leak, so I'm pretty concerned and it's keeping g me from fishing where I really want to for safety reasons. I've sealed all pole holders and Ama brackets with 5200, so I know for sure it isn't that. It's driving me crazy because I can't find the leak and it's big enough that I should be able to very easily. Only thing I haven't done is seal the circle hatches with 5200 as the gaskets all looked in good shape. Please help if you can!

Taking on that much water suggests that the leak is below the waterline.
The most common leak sources would be the drive well ledge or a scupper.
Check very carefully in those areas. The drive well crack may only open under pressure when using the mirage drives.
I found a leak from a split scupper by using an air bed pump jammed into the drain plug. When it was on the water bubbles were clearly visible.
Some leaks can only be found by using the kayak normally as the pressure from sitting or pedaling can cause small splits to open. If you could take an air bed inflator with you while actually on the water you’d have a better chance of finding it.
Good luck!