Fuel consumption

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Lshulan

Senior Member
Joined
Jan 10, 2022
Messages
156
Vessel Name
Voyager
Vessel Make
Mainship 390
I’m looking at a possible purchase of a Mainship 350 which has twin Yanmar 4LH-DTE 150 hp engines. I’m trying to get a reasonable estimate of fuel consumption when cruising, not WOT. Anyone have any first hand knowledge of this? Also, anyone know of any Mainship 350/390s for sale in the model years 1998-2002?
 
Cruise speed is everything. Can you cruise at 6kts. If so it’s a gallon an hour. You want to cruise at 12kts try a gallon a mile. What speed do you want to cruise at?
 
I’m new to trawlers so I don’t have all of the answers but I guess what I’m asking is for an average cruise speed of say 7-8 knots, how much fuel am I going to burn? Looking forward to doing the ICW from NJ so around in round numbers 1000 miles each way, trying to see if I am going to burn 1000 gallons or 500 gallons (each way) if cruising at 7-8 knots for example
 
Wild guess but maybe 1.5-2 gph at 7-8 knots
 
But clearly it depends on the boat (Mainship 350/390) and the motor(s) horse power as well on cruising speed. So does anyone have any first hand knowledge of fuel burn with these two 150 H0 Yanmars ?
 
I push my 14.5' wide, 44 ft boat at just above hull speed, on 200 hp twins, at 8 knots, for 1/2 gpm. My guess is you would do the same with a Mainship powered by twin 150 hp Yanmars. Your stern wave height will measure your gpm. You want to go faster, that wave height will rise, linearly with fuel consumption, more on that shorter boat.
 
Not sure this helps but my Mainship 390 has the CAT 3126 and gets about 2.5 mpg at 8-9 mph. The cruise speed I like is a little above hull speed with just a little bow rise.

Hawk
 
Not sure this helps but my Mainship 390 has the CAT 3126 and gets about 2.5 mpg at 8-9 mph. The cruise speed I like is a little above hull speed with just a little bow rise.

Hawk

2.5 mpg at 8-9 mph is 2.15 nautical miles per gallon at 7-7.6 kts.
 
Just food for thought: fuel is likely not going to be your biggest expense with a cruising trawler. Maintenance, repairs, insurance, slip rental, improvements can (and usually do) all cost more than diesel. My 2 cents.
 
I’m new to trawlers so I don’t have all of the answers but I guess what I’m asking is for an average cruise speed of say 7-8 knots, how much fuel am I going to burn? Looking forward to doing the ICW from NJ so around in round numbers 1000 miles each way, trying to see if I am going to burn 1000 gallons or 500 gallons (each way) if cruising at 7-8 knots for example
Short answer : For the MS39/40, 500 gals for 1000 nms.

But here's a longer answer that may provide context to help decide the overall budget. Most people doing the ICW/Loop seem to average around 75 nm per day. Figure 35-40 gals per day when you're on the move.

Longer term, most boats average less than 200 hours per year. Works out to around 600-800 gals of diesel. 200 hrs per year is a fairly active cruising schedule - if daily average is 4-hrs, that's 50 days underway. Fuel cost is in the $3k-$4k range, or around 10% of the full time cruising costs with some anchoring, some marinas, some eating out, some inland travel.

For the type of cruising OP describes - displacement speeds in ICW, would be hard to imagine fuel costs being a tipping point. The most credible ICW/Loop cruising budgets I've seen where people balance anchoring with marinas is around $40k/yr all-in with doing much of their own work, repairs, replacements, and maintenance averaged, and a fairly normal lifestyle. Of course, there is a very vocal group of chest-thumpers who proclaim very low annual costs by never going into marinas. For them, fuel costs are meaningful (assuming they are cruising vs a derelict)

Good luck.

Peter
 
I’m looking at a possible purchase of a Mainship 350 which has twin Yanmar 4LH-DTE 150 hp engines. I’m trying to get a reasonable estimate of fuel consumption when cruising, not WOT. Anyone have any first hand knowledge of this? Also, anyone know of any Mainship 350/390s for sale in the model years 1998-2002?
See Attached single Yanmar 370HP Everything is for sale it just depends on what you want tp pay. Cheers
 

Attachments

  • Fuel Burn Cartouche.pdf
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Cartouche,
Looks like your chart is close to my numbers translated from above:

2.5 mpg at 8-9 mph is 2.15 nautical miles per gallon at 7-7.6 kts.

That was what I experienced over the last two fillups of approximately 1oo gals of fuel each time.

As others have stated, fuel is the least of the major costs of owning a boat like these.

Hope you get lots of warm weather soon!

Hawk
 
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