CAL 36 mast compression beam

[kapitany]

Hi,

I have a CAL 36 sailboat, recently I discovered that the steel beam under the compression post and fiberglass is partially rusted. Only access is from the bilge and the port side locker.
I didn't know that the mast is actually "sitting" on a beam across the bilge? I discovered it when I traced a hose under there in the bilge and found rusted metal pieces.
It looks to me that it will be a major project to replace or repair it?
Anybody with experience on this? I'd appreciate any advice!
Thank you!