I think CHB;s are made in China. I would look to see if it has steel tanks. I have heard this has been an issue as they get older. There could be as many as 4 diesel tanks in that boat. Also check the wiring depending on the boats age, there was a period of time many 1970 and 80's trawlers built in Asia had substandard wiring, Some of these vintage trawlers also had leaking windows that cause interior rot. I'm sure Al will stop in. I have been looking at Trawlers that size and doing some research.
Bill