Trawler Fuel Consumption

[cat man do]

Originally Posted by Boracay

We've a John Deere 4045D in Boracay, rated at 80hp continuous at 2500rpm. Cruising at 1800 rpm over smooth water we get about 6 knots and burn about 5 litres an hour. That's about 4.6 nautical miles per US gallon.

Nice sounding motor Boracay though a bit heavy for me.
Says 71hp on the site, not 80hp

[boatpoker]

I delivered a 5260 Regal with twin 435hp Volvos with IPS drives (love that joystick) from Toronto to Duluth MN Last September. Didn't keep track of the fuel usuage (not my money) but did sign for $1,200. to fill her up every day for six days.

[18Bravo]

Originally Posted by Seasalt

Perhaps I missed it, but I have not found a concise compilation of owners' reports of actual fuel consumption for trawler yachts with various engines. This information would be very helpful to me and I expect it would be to others as well. I have found a few reports scattered through miscellaneous threads, but no comprehensive thread on trawler fuel consumption. What I have in mind would be similar to the comment posted by "Boatpoker" in November of 2008, as follows:
"My 38 year old trawler with a 38 year old Perkins HT6-354 (diesel and turbo-charged) went to 20,000 hours before we rebuilt it 2 years ago. It makes the run from Toronto to Dry Tortugas or Bahamas and back on less than 800 gallons at 1.6 US gallons per hour at 1600RPM and 7.5 knots."
I'm sure that this group could provide a lot of information on this topic.

Thanks for any contribution that you can make.

Dick Allen
Still Shopping

Dick,

You will find a realistic discussion of fuel use versus hull speed and vessel displacement in Beebe's Voyaging Under Power. I highly recommend it as a reference for the data you are seeking. FWIW - I have a 88,000 lb displacement hull with a 250 hp 6cyl Cat (natural) and I get 2.3 nautical mpg running just above hull speed (with a clean bottom).

Regards,

[Boracay]

cat man do
You do bring up a most interesting point.

The engine you refer to is their industrial, not their marine engine.

Checking I find that the PowerTech 4045DFM70 Marine Engine produces 60 hp at 1800 rpm and 54 hp at 1500 rpm
My receipt says that I have the 4045DFM50. The PowerTech 4045DFM50 Marine Engine produces 84 hp at 2500 rpm at an M2 power rating.

Given just how comfortable the engine is at 1500 and 1800 rpm I must check my compliance plate more carefully.

[Oldcrow]

1984 3870 bayliner 10 liters/hr at 7.5 knots 2 BY260 Yanmar

[Seasalt]

Thanks to everyone who contributed. I will be checking the references that were offered. I will also try plotting the data to see if it fits the theories. When I have time.

Dick Allen

[FlyingDog]

I don't find Boracay to be accurate in the statement about semidisplacement boats. Sounds like he may have been swamped by a wake once to often. I have a semidisplacement pocket trawler, (Devlin Surfscoter27) with a Volvo D3-160. At hull speed, (7knots?) we burn 3/4 gal an hour for a fuel consumption of about 10 mpg. At 15 knots we burn 3.5 gal per hour. At 20 knots we burn 5 gph. Since it has a real time fuel burn rate it is easy to calculate your fuel burn. Real data is helpful. Berating another's choice of boat helps no one.

[Boracay]

No offense intended but I would not rate your boat as a semidisplacement trawler. It looks pretty close to planning in the photo.



The Volvo D3-160 looks like a fine engine and to give the fuel consumption figures that you quote. At 160hp as opposed to the designers website engine power of 105hp the boat must move pretty well.

I do trust that you don't go close to moored boats at full speed.

Nice looking boat.

[FlyingDog]

Boracay, looks can deceive. The Surfscoter is a true semidisplacement hull. With enough power and trim tabs a semidisplacement hull will plane so don't be mislead by the photo you found.
Second the power listed at 105hp on Sam's web site, (devlinboat.com) is the engine that was originally suggested for the 22' version which weights about half of the weight of a 27'. Yes the boat will move along pretty well, although that wasn't the reason for the engine package I chose to use when I built the boat. During the sea trials we hit 27 knots at 4000 rpms. Since then I only do that once a year to make sure the engine is still running up to its potential.

I can tell from your comments that you have an issue with power boaters. I can understand why but as with all things lumping people into broad catagories is a recipe for being wrong some of the time. We typically run at about 8-10 kts and are very courteous to others around us. I learned everything I know about boats and seamanship from 10 years of commercial fishing so when the time came for me to build a boat power is what I know.

Originally Posted by Boracay

No offense intended but I would not rate your boat as a semidisplacement trawler. It looks pretty close to planning in the photo.



The Volvo D3-160 looks like a fine engine and to give the fuel consumption figures that you quote. At 160hp as opposed to the designers website engine power of 105hp the boat must move pretty well.

I do trust that you don't go close to moored boats at full speed.

Nice looking boat.

[Cloud IX]

42' semi displacement raised pilot house trawler, 40k pound, single Cummings QSB 380 -1500 rpms=7knots @ 3.2 gph
-1600 rpms=7.8knots@3.8 gph
-1800 rpms=8.5knots@6.5gph
-2100 rpms=9.5knots@10.3gph
-2700 rpms=12knots@24.5gph.

[David M]

You need to go to the engine manufacturers website to get the GPH figures at a given RPM/horsepower. As far as the boat goes, it takes a given horsepower to go a given speed and that number varies with the hull. That figure might be available at the boat manufacturers website or by checking online reviews of the boat that interests you.

[pjconnors4]

years of cruising 65' eldridge-mcinnis trawler with twin 671 diesels: 9.5kts=10 gals. per hour or 1 gallon per mile.
i year with 54 searay sundancer with twin 650 hp cats: 35 gals. per hour at 25 kts. = 1.3 gals. per mile

[eyschulman]

This is a complex issue and would be difficult to get any meaningfull info unless a lot of detail is known about the specific boats/motors/and measurement methods are known. You can look at two almost identical boats and find significant fuel burn difference. Some of the questions to ask -what is bottom condition- what prop and condition- what transmission ratio-what is state of motor function-what is weight of boat with gear and tankage. A rule of thumb indicator of fuel burn for a boat type based on hull type motor and stern gear and waterline lenght and weight can be roughly approximated and an expereanced boater or marine archetect knowing these details can make a fair guess. A specific boat as is often done with new motor boat models can be taken out on sea trail and recordings made (often optimistic). This information is probably as acurate as you will get. You could also sea trail and record on any individual boat. I would not count on crossing an ocean based on fuel consumption quoted by another boat owner without some considerable detail knowlege of the boat and how that data was obtained.

[BessLB]

We are a 35ft sundeck trawler, single Perkins 135. We generally run at 2100 rpm and get 2.5-3 gph, at 7.5-8kts.

Is it spring yet?

[Highlander40]

OK this is not a trawler. 40' 20,000. lbs displacement twin yanmar 420 hp
waterjet drive 30 kt cruise @ 32 gph.

By packing light we go 4 or 5x faster / farther. Arrive fresh and still burn about 1g/mile.

Average speed over 20,000. nm - 15 kts

Cruising doesn't have to be slow. CT to Maine 1 to 2 days (short days)

Best day ever 200 nm sunrise to mooring at 2:00 pm