I have Cat 3116 straight 6s in my 1993 GB42. I typically cruise at about 1800/2000 RPM, 70-80% rated RPM at about 10K speed. Get about 1.2 NMPG at that speed. I donít work on the engines (only let Cat mechanics turn those wrenches) other than oil changes but I do all the other support/systems repair & maintenance with room. Itís tight sometimes, but Iím not a small guy either!!
I looked at boats with all different engines, happy with my choice as it provides good economy and engine room space. Oh, and you canít beat the sound of a CAT engine!!!