Just and educated guess here from what is installed on mine.
One on the left is the temp gauge sending unit.
One on the right is for the engine high temp alarm.
One on the left is an interlock for the charging system "operates on oil pressure, closes at 15 psi".
One on the top right is the oil pressure sending unit.
One on the bottom right is the engine oil pressure alarm "15 psi and falling".
What kind of boat is that?