Will anyone share their "Real World" fuel consumption?

[cuttyhunk47]

Like most of you I suspect, in my past boating life, I kept record of our fuel purchases and compared them to our engine hours of operation and would be able to calculate what I refer to as our "real world" gals/hour fuel consumption. Therefore, over a long trip, like a three week trip up the ICW or over a certain time period, such as for the past year's boating season, I could calculate fuel consumption for that period of time or distance.

My wife and I are about to get back into the cruising life with a new (to us) Hatteras, with 800 hp Cats that will be a significantly different experience for us compared to our twin 210 hp Cats that we had on a Marine Trader.

I understand that there may be some of you that cruise at displacement speed and then bring their boat up to cruising speed for a time at the end of their cruising day. What are your over-all, final consumption numbers for that type of cruising over a period of time?

Some cruise at typical cruising speed when they can. What is your fuel usage history? I'm not looking for a consumption of your vessel at cruising speed. I am looking for total usage history over a boating season or over a significant distance (like a trip up the ICW).

If you are heading up the ICW, I'm sure there are times when you are stuck at displacement speeds and there are other times in high traffic areas where you are not up to cruising speed.

I would be grateful if any of you would share your "real World" fuel usage over a considerable period of time or considerable distance.

[RonNP]

I brought my boat up from Ventura California to Stockton California this past October. A total of 386 NM. The engines are DD 12V71Ti and I had one Onan 20kw generator running the entire time. Did hull speed of around 9 to 10 kts the entire time going uphill as we say on the west coast which means I was fighting the Gulf of Alaska current going down the west coast of the US. It added around a 3mph head current the journey. Burned right around 500 gallons which worked out to .77NMPG. Will refill tanks with San Francisco priced diesel at $4.21 per gallon so total cost in Diesel for the 44 hour long trip was $2105

[Pascal]

You mileage will vary but...

I ve done the 1600 NM run between Miami and Nantucket 4 or 5 times (round trips) and would usually burn 3200 to 3500 gallons running 90% of the trip at hull speed with 70 footer and 1400Hp 3412Es. That includes about 18 to 20 days of generator. (That boat used to burn about 18GPH say 10 kts and 80GPH at 20)

If you re looking at a 60 with 800hp, i d plan on 13 gph at 9.5 and 60 gph at 20kts Figure about 150 USG for each 100nm including a short run on plane at the end.

What is critical is not to run between Hull speed and planning speed. I5% above hull soeee is going to DOUBLE your fuel burn.

Rule of thumb which works for most boats capable of cruising at twice its hull speed: . every hour on plane cuts an hour off your trip but cost you twice the fuel for each hour on plane

[cuttyhunk47]

I brought my boat up from Ventura California to Stockton California this past October. A total of 386 NM. The engines are DD 12V71Ti and I had one Onan 20kw generator running the entire time. Did hull speed of around 9 to 10 kts the entire time going uphill as we say on the west coast which means I was fighting the Gulf of Alaska current going down the west coast of the US. It added around a 3mph head current the journey. Burned right around 500 gallons which worked out to .77NMPG. Will refill tanks with San Francisco priced diesel at $4.21 per gallon so total cost in Diesel for the 44 hour long trip was $2105

Thank you sir. Very helpful!

[cuttyhunk47]

You mileage will vary but...

I ve done the 1600 NM run between Miami and Nantucket 4 or 5 times (round trips) and would usually burn 3200 to 3500 gallons running 90% of the trip at hull speed with 70 footer and 1400Hp 3412Es. That includes about 18 to 20 days of generator. (That boat used to burn about 18GPH say 10 kts and 80GPH at 20)

If you re looking at a 60 with 800hp, i d plan on 13 gph at 9.5 and 60 gph at 20kts Figure about 150 USG for each 100nm including a short run on plane at the end.

What is critical is not to run between Hull speed and planning speed. I5% above hull soeee is going to DOUBLE your fuel burn.

Rule of thumb which works for most boats capable of cruising at twice its hull speed: . every hour on plane cuts an hour off your trip but cost you twice the fuel for each hour on plane

Excellent information. Thank you very much. Just what I was looking for.

[captainwjm]

What is critical is not to run between Hull speed and planning speed. I5% above hull soeee is going to DOUBLE your fuel burn.

Absolutely right; on my 65' w/ 3406 CATS my GPH at 9.5 kts is 9.2, but at 10.9 kts, it's 21.4.

[Briankinley2004]

My average trip I run in the gulf has been in 2-4’ seas. I would run hull speed (9 1/2 knots) and cruise at 1900 for 15 minutes every 4-6 hr. It seems I burn about 1.6-1.8 gallons per nautical mile including the generator. This is idling engines when fishing but stopping at night with generator on. My hull is dirty as wel.

[Hat52MY]

With 8v92 DDEC and 20KW generator we typically run in the Atlantic, Bahamas & ICW. Also poke along at hull speed (9 1/2 knots, 1200rpm, 14gph including generator) and cruise at 2000 for 10-15 minutes every 4-6 hr (60 gph). We also tow a 22 center console about 50% of the time, which surprising only adds 1gph to the total. On cool nights/days we run on an 5KW inverter, which saves 30 - 35 gallons per day. All-in-all we range between 14 to 18gph when the boat is moving, most trips average 15gph. When planning for trips, I always use the high end of 18gph for fuel consumption and always return with a surplus.

[doc g]

Delivery trip home .............North Captiva to Naples to Indian Key to Fort Lauderdale via Channel 5 in the Keys - 386 NM 1020 gallons . FLL to New Smyrna outside to Mount Pleasant SC- 1079 gallons. Mount Pleasant to AYB in Norfolk- 1190 gallons . Total for trip 1232 NM, 3289 gallons , 0.375 nm/gallon. 1999 74 SD 1350 Cat s with 20 kw Onan running the entire time . Combination of running at 20K @64 GPH, 10 K at 13GPH. When it was rough, needed to make time, and had day light we were planning. At night or not trying to make a certain stop point we did hull speed ......Pat

[cuttyhunk47]

I want to thank everyone for their input. This was exactly the information that I had hoped for.

Frankly, the larger engines scared the hell out of me. I had heard and read about 60-80 gph at cruise and would try to estimate the percentage time at cruise and the percentage time at hull speed. I was guessing 50%?, 60%?, 70%? of the time at cruising?

I had read about operating at hull speed with bursts at cruising to end the day, but I thought that was more of a theory and not regular practice. Nothing like real every day experience. Thank you all again.