Best marine HF receiver I ever used from a corrosion resistance standpoint was a surplus R 392. We used it mostly as a galley morale radio listening to SWBC and especially sports news on Armed Forces Radio Network. It did ok as a backup communications receiver too. SSB could be copied using the BFO. It wasn’t hifi but it was good enough. We fed the audio into an outboard amp for adequate speaker volume. 

That radio was SEALED. It even had seals on the control shafts. During a commercial fishing trip the front panel would get very messy with fish scales, blood and so forth. We’d unplug it, take it out on the deck, throw some dishwashing detergent on it and wash the front panel with a powerful fresh water spray. No harm, no water intrusion and it cleaned up really nice. 

Mark

AF6IM