Welcome to the forum.
The two ell bend steel then rubber hoses are for power steering. They are about $150 each.
https://www.mercruiserparts.com/bam/subassembly/30914/1604/240
This is a good time to clean up and protect those parts.
My suggestion would be to scrape off all the rust, then lightly sand, then paint w/ Rustoleum.
Same process for all the other rust, including on the engine block.
Maintain the engine and parts to limit deterioration, failure and replacement costs.
