Trawler Fuel Economy

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Here are the fuel burn numbers:

"Starting at $850,000 (New Zealand $, or about $570,000 US) , its affordability is enhanced by the boat's extraordinary fuel economy.

In flat water, lightships, on this 58ft, 14-tonne vessel, we recorded:

• 7.2kts using 0.55 litres diesel per nautical mile

• 8.1kts using 0.67 litres diesel per nautical mile

• 9kts using 0.84 litres diesel per nautical mile.

Well, just like putting solar panels in your yard to "feed the grid" there's a payback time..... $370,000 buys a lot of gas, but I should be breaking even on my 127th birthday.... yipppeeee. If only I was 18 and wealthy.

Awesome technology though.
 
Also consider that the most distinctive feature than makes a trawler a trawler is it's weight.

The fact that the recreational boating industry has, for marketing reasons, adopted the term "trawler" to describe a remarkably broad spectrum of powerboats means there is actually no correct definition of the word. Eric thinks it's defined by weight. The folks at Nordic Tug or Ranger Tug would disagree, as they consider their lighter, faster boats to be "trawlers," too.

There is only one definition of the word "trawler" that draws no arguments from anyone and that is that it's a type of fishing boat. Every other definition draws opposition from someone if not many someones.

Leaving aside the fishing bit, I don't use the term "trawler" in connection with recreational powerboats but if I did weight would not be part of the criteria in my mind for being this type of boat. I can see why Eric does and I don't fault him for it, but because the term has become so corrupted by using it to describe so many different types of vessels, I tend to think of the term as more the function of the boat rather than any one physical attribute.

In my opinion, the term "trawler" has become synonymous with the term "RV." RV encompasses a whole host of types and configurations. Trailers, fifth-wheels, single axle, tandem axle, tripple axle, pop-up trailers, and all the different classes of motorhomes. Out of all this, what is the one common denominator?

How it's used.

I think the situation is identical with boats and the term "trawler." It no longer defines a specific configuation or set of performance factors or physical characteristics. The marketing departments and ad agencies have seen to that.

What is the one common denominator that encompasses our 43 year old. twin-engine Grand Banks and the brand new Ranger Tug down the dock and a Nordhavn and a Bayliner 3888 and an American Tug and a Nordic Tug and a CHB and a Californian and Eric's single engine Willard and Mark's steel-hull, sail-assisted Coot, all of which are referred to as "trawlers" today?

Same as the RV. How it's used.

That's the only all-encompassing definition left now. Every other definition is open to argument. Eric says weight. A number of manufacturers whould disagree. Some say low speed. A number of manufacturers and owners would disagree. Some say physical appearance. Manufacturers and people with boats that don't look that way would disagree. Some say low fuel consumption. The owners of Grand Banks boats with big engines who like to cruise at 16-18 knots would disagree. Some say displacement hulls. People with semi-planing and planing hull boats would disagree.

Some might say range, and this is actually plausible as it ties in with how "trawlers" are used. So are terms like "comfortable," "good visibility," "good ride," and so on. But none of these terms describe a particular kind of boat, they describe the attributes one wants in a boat and there are lots of ways to get them.

The term I prefer for the type of boats most participants in this forum have is "cruiser," or as Eric llkes to say, "heavy cruiser." But these terms,too, are not definitions of physical or performance attributes but how a boat is used. You can cruse at 6 knots and 1.5 gph and you can cruise at 40 knots at 60 gph.

So when one sees the term "trawler" used in a manufacturer's sales brochures or ads, or applied to an ad on Yachtworld, or even as used by the members of this forum, just think "RV." You will be 100 percent correct every single time.:)
 
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Marin,
Good post.
The boats we call trawlers now were called "heavy cruisers" as in your post above. They separated normal cruisers from what we call trawlers by referring to their greater weight in the name that was used at the time. Should have never changed IMO. The old wood "Monk boats" of about 40' were typical of the heavy cruisers.
 
Even if it doesnt walk like a duck or quack like a duck you can still call it a duck if you want it to be a duck bad enough. The folks that actually own "DUCKS" know what a duck really is.
 
I just figured out that I did 133 hours this year. That was including about 3 hours a day of genset (I got a nice big battery charger that chopped 2 hours off the charging time) and my Hurricane heater in the evening in the winter, probably 4 hours/ day on average. That means that the fuel cost was about $20.50 per hour or about 20% of the average yearly costs I have on a recurring basis. Including haul outs and zincs. We currently have fairly low fuel prices but if it went up 25% to where it was before the crash, it would only be $25 per hour, which is pretty darn cheap and getting to the point where serious attempts to cut fuel consumption will result in being cold (less heater use) or killing the batteries (less genset). Each device is rated at 1 gallon per hour and I think that's very close. So, before I even start the engine I have committed to 7 x 4.6 litres or 32 litres for $35.

Go back and see post number 5, he's correct.
 
I've had this exact same question regarding fuel consumption recently comparing displacement, semi displacement and planning hulls. From the research I've done so far my conclusion is it will depend on a lot of factors and really comes down to the individual boats you are talking about. The only way to determine fuel economy on that individual boat is to find someone who has one and operates it or operate it yourself for a time. You will find there are planning hulls that can be operated even more economically than some full displacement hulls around the same size but it all comes down to the hull/engine combination and how it is driven. This is a couple of links to a site with people who have had and operated both planning and full displacement boats and know exactly their operating figures.

Bayliner 4087 | MV Dirona
MV Dirona Specifications and Features

The other thing I have found is that the idea that operating high powered engines at low power for long periods does them damage is something of a myth. I wouldn't say it completely unfounded but I have done it myself with Volvo and Caterpillar engines for many thousands of engine hours with no ill effects. I have also talked to and found many others with different engines but the same experience.

My suggestion would be find a boat you like and research that one to find its true economy the way you want to operate it.
 
Take the same path in a single engine trawler like the N46 at lets say for discussion sake 3.0 NMPG and the monthly fuel cost drops to $465 a huge difference! .


Kevin it would seem to me that people do not buy Nordhavns to save money. The general consensus among N owners is they buy their vessels so they can go long distances without the need to refuel. This long distance travel requires about a 1.5 to 2 nmpg fuel burn at 6.5 to 7 knots.

Purchase and upkeep of a Nordhavn are not small sums so from the standpoint of frugal boating, it is not done in a Nordhavn. Unless of course it stays at the dock which defeats the purpose of owning one.
 
No on many counts. Nor as they normally advertised as one.


Tom I'm think'in the classic GB's of the early 70's is about as trawler as you can get. Wer'nt they the original trawler? Sure there were Willards that pre-date the classic GB's by 10 years but by classic I'm think'in a typical trawler like a GB, CHB and Marine Trader.

Advertiseing dosn't count as it's bottom line is manipulation not a tool for truth and fact.
 
Tom I'm think'in the classic GB's of the early 70's is about as trawler as you can get. Wer'nt they the original trawler? Sure there were Willards that pre-date the classic GB's by 10 years but by classic I'm think'in a typical trawler like a GB, CHB and Marine Trader.

Advertiseing dosn't count as it's bottom line is manipulation not a tool for truth and fact.

You are right Eric, the early ones were indeed trawleresque if you will. But then came the 80s and any thought of a GB trawler quickly became a fleeting memory.
 
Getting back to the idea of what boat you are interested in.... I will share my criteria when I was shopping for a boat. I wanted flush deck from the inside helm to the stern. I wanted a cockpit I could walk out to, carrying food, cocktails or stuff without having to climb up, down and back up ladders to get to. I wanted a cockpit large enough to sit a couple chairs in. I wanted a cockpit that I could throw a fishing rod from.

Many of the 'trawlers' mentioned in this forum are 'down, up, down design. Meaning climbing ladders to go from the front to back inside. That was a deal killer for me. I want to be able to see all the way from the chain locker back to the transom. Toting my Grandkids around I wanted excellent visibility, side decks and a big flybridge. I also wanted both upper and lower helms. Your requirements may be different. Keep looking until you find what you want. (Then again, that may change as you are looking!)
 
- cruise at 1000 RPMs = approx. 7 GPH @ approx. 7.5 kts "

The usual displacement trawler might get by at 7.5K with 1/2 to 1/3 the fuel burn.

The price to go fast is being paid in fuel as well as engine life.

Folks that prefer the Trawler Crawl might do best with a trawler, the price of speed is Always high.
 
Genecop - Welcome Aboard!

Having reviewed this thread and seeing that much of the Trawler definition BS as well as the gph graphs/discussion has been well gone over again (go to search feature - there are many threads about all this stuff)...

I offer this advice.

1. Read all you can about boats and their designs.

2. With your Admiral go and look at (get aboard) as many different design boats as you can.

3. You two make up a list of what each of you would like to have in a boat and to have the boat do. Be careful to be honest with yourselves regarding what you need as well as what and how you will use the boat for.

4. After you have your list - post it on TF. There will be plenty of clarified suggestions offered. Also, go to search feature to locate plenty of threads about such.

5. Unless you plan to cruise continuously putting on much mileage per year... don't let fuel use get too heavy on your mind. For vast majority of boats i.e. FD / SD / P... go slow and use much less fuel; go fast and use much more. If your annual boat budget has enough flexibility to absorb a plus or minus five hundred to one or even two thousand dollar change in fuel costs... then all is OK! It's the boat design and comfort features I believe you should focus on!

BTW: $2000 divided by 52 weeks = only $38.46 The cost of even more enjoyment aboard a Pleasure Cruising Boat!

Happy Boat-Chosen Daze! - Art :speed boat:
 
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Got a "workboat" hull. Got heavy displacement. Got a low-powered engine. Got living accommodations. Got range (1000-1500 miles). Can just keep up with the local fishing trawlers. All I need to fully-qualify as a trawler is a dragging net.

 
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Getting back to the idea of what boat you are interested in.... I will share my criteria when I was shopping for a boat. I wanted flush deck from the inside helm to the stern. I wanted a cockpit I could walk out to, carrying food, cocktails or stuff without having to climb up, down and back up ladders to get to. I wanted a cockpit large enough to sit a couple chairs in. I wanted a cockpit that I could throw a fishing rod from.

Many of the 'trawlers' mentioned in this forum are 'down, up, down design. Meaning climbing ladders to go from the front to back inside. That was a deal killer for me. I want to be able to see all the way from the chain locker back to the transom. Toting my Grandkids around I wanted excellent visibility, side decks and a big flybridge. I also wanted both upper and lower helms. Your requirements may be different. Keep looking until you find what you want. (Then again, that may change as you are looking!)

Sounds a lot like my trawler! :thumb::thumb:

img_390166_0_a65eac6f9fdb145b47b3c525c9d8e704.jpg
 
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  • This said it well:
    Recreational trawlers are pleasure boats which resemble fishing trawlers. They can also be called cruising trawlers or trawler yachts. Within the category, however, are many types and styles of vessels. A fishing trawler for example, always has a displacement hull for load-carrying capacity, and a towed net.
    Then there are Troller boats. :)


 
With $2.00 gasoline here in many places , and $2.00 diesel on the way , does fuel burn really matter that much any more?
 
Fly: A great picture of a boat using fuel to move water instead of the boat. That PIX should be shown to all the "hull speed" fans.
 
Fly: A great picture of a boat using fuel to move water instead of the boat. That PIX should be shown to all the "hull speed" fans.

Yup, I bet he is burning 3- 4 gph, sinful.
 
Fuel prices when adjusted for inflation are currently pretty low. At the same time prices when they are 'back up' are still not that expensive when looked at over a longer time period. Sure it feels like fuel it high when I compare it to buying marine diesel at $1 gallon but a lot has changed in all our lives since those prices. Even though it may feel costly as prices rise it is the comparison to what we earn and what all other costs are that make the real difference.


Inflation Adjusted Gasoline Prices
 
Fuel prices when adjusted for inflation are currently pretty low. At the same time prices when they are 'back up' are still not that expensive when looked at over a longer time period. Sure it feels like fuel it high when I compare it to buying marine diesel at $1 gallon but a lot has changed in all our lives since those prices. Even though it may feel costly as prices rise it is the comparison to what we earn and what all other costs are that make the real difference.


Inflation Adjusted Gasoline Prices

Very informative! Thanks!!
 
My numbers

This weekend I finally took the time to do some fuel consumption tests. I took measurements in two passes in opposite directions to cancel out the flood that I was facing. Here are the results:

Kadey Krogen 54 - John Deere 6068T 225HP - 1200 US gal fuel tanks

Speed nmpg range (nm)
5.3kt - 3.5 - 4200
6.0kt - 3.0 - 3600
6.9kt - 2.5 - 3000
7.5kt - 2.0 - 2400
7.8kt - 1.5 - 1800
9.0kt - 1.0 - 1200

Of course these were calm waters - extra fuel would be required to push through waves. I hope to get some measurements in different sea states. Also - the range assumes no reserve fuel - I would want 20% reserve.

Note that this assumes my FloScan is accurate. This will need to be checked at some point.

This isn't purely academic. When I retire I'd like to head to the South Pacific via Hawaii.

Richard
 
My boat gets from 3.5 NMPH at 7 knots to 6 NMPH at 6 knots.

Yanmar 4JH4-HTE. 1800 rpm burns about 1gph at goes about 6 knots. 2200 rpm burns about 2gph and goes about 7knots. Based on Yanmar fuel curves.

Tank pretty small at 200 gallons with 10% reserve so range is only 700-1200 nm based on speed and no genny.

Real world experience:
With the genny running almost constantly while underway (and at night some also) and running at 7 knots I averaged about 2.5 gallons per hour underway from Clearwater FL to Rockport TX.
 
Tom I'm think'in the classic GB's of the early 70's is about as trawler as you can get. Wer'nt they the original trawler?

Advertiseing dosn't count as it's bottom line is manipulation not a tool for truth and fact.

Of course advertising/marketing counts. That's the only reason the term "trawler" was applied to recreational boats in the first place, to project the attributes of a seaworthy fishing vessel onto a recreational boat that looked vaguely like one in the hopes that buyers would think it more capable than it really was. It's all about image.

Grand Banks did not call their boats "trawlers" until fairly recently when the general use of the term for marketing purposes became so pervasive in the recreational boat market they were pretty much forced to adapt it themselves.
 

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Note that this assumes my FloScan is accurate. This will need to be checked at some point.

This isn't purely academic. When I retire I'd like to head to the South Pacific via Hawaii.

Richard

Richard, you are a bright guy and know this - once you get to the point to do the South Seas, a day tank would be a nice to have thing. Day tanks allow very precise fuel measurement thus negating the vagaries of solely relying upon floscans.
 
Another advantage of the day tank is that any fuel that goes into it has been filtered/dewatered befor it gets there. My trawler has two 30 gallon day tanks above the engines in port and stb settees in the saloon. I know, you're gonna tell me that fuel shouldnt be above the fuel pump. And I agree, but it sure makes filter changes and priming easier. And air in the lines is NEVER a problem, because the system doesnt "suck" in either way. I have a 1/3 hp gear rotor pump for cleaning fuel ( thru large dual switchable Davco units) and moving it between tanks. The day tanks have float switches that turn the 12 volt tranfer pump on and off at preset levels. They normally pump 10 gallons at a time. I have a water witch cycle counter that keeps track of the number of times the pumps run. This makes it fairly easy to calculate gph. the entire fuel system is seperated, port and stb, but fuel can be transfered by the gear rotor pump to any of the 4 lower tanks. I have two 500 gallon "bulk" tanks that are the only tanks that can take on new fuel. I have two 150 gallon tanks that recieve filtered fuel from the bulk tanks. 12 volt transfer pumps move it from there to the day tanks. The bulk tanks can gravity flow into the mid tanks if neccessary but I like to run it thru the cleaning setup first. The gear rotor pump is valved so as to be able to circulate and clean any of the tanks, except the day tanks, which can be emptied into the bulk tanks by gravity and accessed thru large clean out hatches in the top. EVERY tank has access to every baffled chamber for cleaning. It all sounds kinda complicated but not once you understand whats going on. Clean fuel is the very very most important thing.
 
Richard, you are a bright guy and know this - once you get to the point to do the South Seas, a day tank would be a nice to have thing. Day tanks allow very precise fuel measurement thus negating the vagaries of solely relying upon floscans.
Thanks! Yes I have considered a day tank. There isn't really a proper fuel manifold on my boat - so at some point I want to build and install one. The challenge for adding a day tank will be finding room for it!

I assume that people us a sight gauge to get an accurate reading of consumption from the day tank? Also - the return would have to be directed there too...

Richard
 
The challenge for adding a day tank will be finding room for it!

The previous owner of our boat replaced the three original tanks with five smaller ones. Four are saddle tanks, the fifth one is a 60 gallon day tank. It is located in the bilge on the centerline of the boat under the engine room floor plates between the aft ends of the inboard engine stringers. In this position it is totally out of the way and uses space that was unused and empty before.

Perhaps something like this could work on your boat?
 

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