2016 Summary

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tpbrady

Guru
Joined
Sep 5, 2012
Messages
1,043
Location
USA
Vessel Name
Silver Bay
Vessel Make
Nordic Tug 42-002
I know a lot of trawler owners and potential owners are interested in long term performance of boats so I thought I would post our summary from 2016:

1996 Nordic Tug 42, 6CTA 420 HP Cummins with 5295 hrs, 39,000 lbs estimated weight

Distance (SM) 2471 miles
Fuel 720 gals
MPG 3.43
GPH 2.03
Engine Hours 354.9

We generally cruised at 1200-1300 RPM (7 -7.5 knots in calm water) and for short periods as high as 1600 RPM. On the last leg between fuel stops where most cruising was on the low side (1200 RPM) and we covered 627 miles and saw 1.84 GPH and 3.9 MPG (I don't believe it but that is how the math comes out so I guess the wind and current were with us a lot).

Tom
 
Dang, Tom. 420 Cummins and all that higher cruising potential and you're getting what I get at 7 knots....., wow! I gotta get me a 42 Nordic Tug.
 
Very efficient Tom. Better than what I think I am getting. I don't have much experience yet however.
 
That's pretty impressive! (From one who is quite conscious of fuel economy.)
 
Dang, Tom. 420 Cummins and all that higher cruising potential and you're getting what I get at 7 knots....., wow! I gotta get me a 42 Nordic Tug.

Larry,
The NT is narrower than most and some or most have rocker in the bottom. May be lighter too.
One point not mentioned by the OP is how the burn rate numbers were computed. Most here look at the hour meter and their fuel reciepts and it seems objective but few really realize how far off it is .. or don't want to know. However the rpms posted are very low and the seemingly good burn may be a result of over propping. Or a number of similar elements can produce good numbers and at time even low burn rates. I'm suspicious of most all fuel comsumption numbers. Execpt my own because I burn so little it hardly matters and haven't "measured" it for a long time. So if you meet another boater that dosn't talk about and seem to care about fuel burn he's prolly not burning much.
 
Eric,

Without a fuel flow meter I can only compute fuel flow numbers using the hour meter and fuel receipts. However, I do see fluctuation between different legs. For example the Garmin MFD tracks average speed while moving. When went to Wrangell from La Conner it showed an average speed of 7.1 knots and the fuel burn for that leg was 2.5 GPH. On our leg with the best fuel burn, 1.84 GPH, the average speed was 6.1 knots. This tracks pretty closely with the Cummins performance graphs for the engine but where we are operating on the graph it is really hard to interpolate the predicted fuel flow.

I don't think the boat is over propped as we can hit almost 2700 RPM at WOT which is 100 RPM over the Cummins WOT RPM for the engine.

Tom
 
Nice numbers there Tom. That's about what I'm getting although I've only got about 300 hours this year. Our best part of the season is still to come this year so I'll post better numbers this December. 2X 4-236 Perkins.


Kevin
 
Over time....

If you fill a tank and use gallons burned from the receipt...compared against hrs and miles....most experienced boaters I know are pretty confident in their numbers.

Sure tides and winds and a few things alter the equation...but after thousands of miles and numerous fillups, the math starts to get pretty acccurate.

I am confident enough in my numbers to plan arrivals with way less than the 1/3 rule rookies should live by.
 
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