T&T: Trawler fuel milage

[Larry H]

I have a 1978 Puget Trawler 37 (Taiwan built) with a single Ford Lehman 120 
hp.

On last summer's trip from Seattle to SE Alaska I ran at 1600 rpm achieving 
7 knots and burned 2.0 gallons per hour for a mpg of 3.5 Nautical MPG(US 
gallons).

The Lehman is an older design, all mechanically injected engine.  Are there 
any newer engines that can achieve the same economy?

Larry H