It is absolutely common and routine for trucks and other commercial diesel
engines to have bypass filtration systems. It is routine for some of these trucks to go 30,000 miles between changes using synthetic oil. It has been proven that bypass filtration does extend engine life significantly in heavy duty applications. You can buy reasonably priced units right off the shelf that take reasonably priced filters. Whether or not it makes sense for your engine is hard to say. I would venture yes on a long-range trawler
that depends completely on its engine and runs it long and hard. The oil savings alone will probably pay for it within a few years. You might want to get 10,000 hours or more out of that engine before it needs a rebuild
. On a lot of sailboats you will probably want to be changing that oil a lot less often just because you just don't use the engine as much, and you use a lot less oil, so less of a factor on cost. Most sailboat engines die from neglect, corrosion
, and other factors long before they wear out or need a rebuild
, so the reduction in wear is harder to justify.