How far can you motor on a full tank of fuel?

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2.5L/hour, 180L tank = 72 hours ... 2.5L/hr = >7knots - that'll be 500Nm then ... hmm - it'll be interesting to see what we do get!
 
Entirely depends on the conditions. Last Sunday I used about 1/3 of a 27L tank to motor-sail about 30 miles in moderately adverse conditions. In flat water I would expect to almost double that to something like 140 miles range.
 
2.5L/hr at 7kts sounds optimistic. At what revs and how many HP in the donk?


To answer the OP, it depends on the engine speed and resultant boat speed, dunnit.

I heard an interesting theory about this just the other day - something like for every 20% reduction from maximum revs, half the fuel consumption. Just a rule of thumb, not scientific.

At 2200rpm, 50HP engine, cruising speed is 7kts in calm conditions, about 5L per hour. 320 L tank. Total range, about 450nm.
 
Nick - its a volvo 2030 with a saildrive - I specifically asked about consumption in another post in R2R ... and it came out approx 2.5L/Hr at 3000rpm.

We motored (with a clean bum and nothing aboard) at 3000rpm achieving 7.5Kts through the water - so I've allowed a bit of a reduction now SWMBO has loaded her up!

We'll see what we achieve this season ... /forums/images/graemlins/smile.gif
 
My Perkins 4-107 averaged 1.6l / hr crossing Baltic at 4.8kts steady. 25ft Motor sailer of about 3.8MT. Sails were up but given wind probably only assisted in very tiny way..... probably 0.1 .. 0.2kt only.

So taking a guesstimate of the consumption and speed - given the 82 ltr tank.

82 litres / 1.7 l/hr * 4.8kts = 231nm ( I added a bit to the 1.6l/hr as margin).

But that's economic setting. Consumption dramatically increases with revs to over 4.5l/hr if I open her up fully but then I get 9kts ... it is 42HP !

I answered on poll at up to 200nm - as I would never want to test how far down the tank I can go. I always aim to refill before I get to 30% remaining.
 
0.53gph @ 6.5kts and 2,000rpm 32 gallon tank so say 30 useable (have another 5 in can) gives 56.6hrs and approx 368mls.

0.66gph @ 7kts and 2200rpm gives about 318mls.

Brunton prop will self pitch 'up' in really calm conditions or with the tiniest bit of wind assist, even with no sail up, so 7kts @ 0.53gph at 2,000rpm.

Engine is Yanmar 4JHE 44hp, 41ft boat. /forums/images/graemlins/smile.gif
 
At eco cruise, 2450RPM, 2.25l/hour (averaged over 550 hours of use). Total tank capacity 140l.
Kiwiprop 3 blade feathering fitted
Clean bum 6kts, dirty-ish bum 5kts

My original 2 blade fixed 17x12 gave better forward performance by 1/2kt at 2450rpm, but slowed the boat when sailing by a similar 1/2kt.

Around 300 miles. in flat water, no wind, no tide. In reality, probably more like 350 miles, as we use wind and tide wherever possible.

On my 3YM30 Yanmar (29hp) the power and torque curves cross at 2450RPm. This is the most economical cruise, as it gives the highest torque to power ratio in the rev range.

If I run the engine at 3000-3200, ful consumption goes up past 4l/hour.
 
As we are a Cat we have twin engines and two fuel tanks of 350L each.
Running only one engine at 2100rpm (54hp Yanmars) we can achieve 6.5knots on a fairly flat sea. Using this scenario we burn around 3.5L / hour so nearly 650 miles per tank or 1300 miles using both tanks.
On the delivery trip when we passed through the doldrums we had to motor for 3 1/2 days solid. This gave us a lot of oportunity to check out our fuel consumption figures!! /forums/images/graemlins/shocked.gif
 
[ QUOTE ]
2.5L/hr at 7kts sounds optimistic. At what revs and how many HP in the donk?


To answer the OP, it depends on the engine speed and resultant boat speed, dunnit.

I heard an interesting theory about this just the other day - something like for every 20% reduction from maximum revs, half the fuel consumption. Just a rule of thumb, not scientific.

At 2200rpm, 50HP engine, cruising speed is 7kts in calm conditions, about 5L per hour. 320 L tank. Total range, about 450nm.

[/ QUOTE ]

Nick, I get around the same on a VP 2003T. However if motoring into a strong breeze and lumpy sea, I recon at the same RPM, it consumes a hell of a lot more juice.

I think I got through about 20 galls going to ST Vaast 75m st vast Cherbourg 15m Cherbourg Portmouth 70M = 160m so giving about 8 miles per gallon. Coming home was a lumpy head sea so 2500 revs instead of 2250.

Range is therefore 45 galls x 8 = 360
 
I only have a 2.5 gallon tank, so despite doing 2 pints an hour at 3.5 knots, the range is not great, or wouldn't be if I didn't carry another 4 gallons in cans, in the fuel locker.
 
120 litres in the tank. Volvo D1-30 saildrive.29hp pushing a 39footer, 3 bladed folder. 2l (ish)an hour at 6 kts, nearer 3 at 6.5 kts as far as we can estimate. Very good if chugging.

Bloody hell, that's 60 hours of flat calm and total boredom then we start rowing.
 
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