Hi All, Anyone with experience regarding the fuel consumption on a Hatteras 70ft from 1979's? I'm interested in what people see as the most economical RPM speed and what corresponding fuel burn they have seen? i'm thinking in the 850 RPM range. Better yet, does anyone have fuel charts for this boat and the DD12v71? A few other technical questions: 1. If you have a 70ft Hatteras from this time how big are each of your fuel tanks and what type of manual way do you have to check the tank level? One I'm looking at, i found some sticks in the engine compartment which are clearly to measure tank levels but i cant figure out how to get in to them. Looking at a longer off shore passage with this and need to understand the limitations. Again, i'm not after speed but economy.
I can't tell you about that model. But I did run a 1988 65' MY extended to 75' MY with 12v71 TI's. At 1000 rpms we burned 12 gph at 10.3 knots. At 800 rpms we burned 8 gph at 8 knots.
Not familiar with the LRCs but ... The LRCs are more efficient than the MYs. your best speed will be just under hull speed or about 10kts. If you slow down even more like 8kts you will save even more although you need to make sure the engines run at high enough temperature most hatts have keel tanks which you can stick thru the fuel gauge sender.
Are you talking about an LRC or a MY? I don't think Hatteras ever made a 70' LRC. I know there's one listed on YW but I believe that was a 65' that was extended. I don't think the 65' LRC had 12V71's so perhaps you are referring to the MY. I think it was 6-71N's. But much different hulls and power LRC to MY. And the LRC's carry north of 2000 gal. of fuel which give them a lot more range than a MY.
Yea 12-71's aint no LRC. Back in the day captains would replace the injectors with small ones for the trip from FL to Puerto Rico. If you are serious about range and need it often consider another boat. You have the wrong tool for the job. 65 LRC's had 6-71's 12V71's will wash the cyl walls with diesel fuel at prolonged periods at 850rpm.
