Open cooling vs Closed cooling

[NHGuy]

Closed cooling is a term I can wrap my meager brain around. To me that's a heat exchanger with coolant running through the block and possibly elsewhere. Closed would indicate recirculating. Am I right?
Conversely open cooling is lakewater, or other outside water through the entire system, true?
Then explain fresh water cooling versus raw water cooling please.

 

[Bt Doctur]

Re: Open cooling vs Closed cooling

FWC, fresh water cooled: A/F in the engine and or exaust manifolds kept at normal operating temp using a heat exchanger system.
RWC, raw water cooled: available water drawn in thru the drive or thru hull to cool engine ,manifolds, and risers