Don - I went back and reread your original post. 3500 hours on a 2001 sailboat actually sounds pretty high - roughly 150 hours and 100g diesel per year. Wondering what kind of boat and how it was used?
I think part of the confusion here is the yardstick you're comparing to happens to be pretty high, at least that's my observation.
Peter
So I said I would answer.
2001 41' sailboat that was New England based first 15 years. So only used weekends for 6 months and maybe a week vacation trip each year.
When I got the boat it had 538 engine hours, so 53 hours/yr
I used the boat EVERY weekend and either just went out and sailed, having of course to get out/in the inner harbor, or went "somewhere". Lots times sailing "somewhere" on a Saturday met a motor back on Sunday to get home. But at end of that the engine had 1100 hours on it after 6 years of my use. We called ourselves sailors back in those days and sailed 3-5 times more miles than we motored. So in 6 years I motored an average of 94 hours/yr on a sailboat that sailed a lot more than it motored and only was used on weekends for 6 months per year plus a week cruised.
So to me a 1985 trawler with 3000 hours, which is 78 hr/yr, seems like very light use. Even this 100 hr/yr on a trawler doing 7-8 knots sounds low milage
The last 6.5 years we have been full time cruisers and have traveled: Salem Ma -> Florida -> Bahamas and back to Fl -> South Carolina -> Fl Keys -> Maine -> Florida Keys -> Mississippi -> Keys -> Bahamas ->Jacksonville Fl -> Keys -> Bahamas -> Jacksonville -> Keys -> Jacksonville -> currently at cat Island Bahamas. Due to family issues, a broken shoulder, and covid we have only really traveled about 60% of the time we planned.
I estimate that we have traveled about 15,000 miles in the 6.5 years and have we motored 2490 hours during that time. So I estimate we have motored about 12,000 of the 15,000 miles, which is why we are thinking to change to a trawler.