Fuel consumption research!!

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the griff

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A friend of mine has asked me if I can get a few figures regarding fuel consumption and different boats. Could you please list the following.

Type/make/model and length of boat

Number of engines

Make/model of engine'(s)

MPG at your usual cruising speed(please state speed)

Any info regarding actual trips and fuel used, average speed, max speed, conditions, miles covered.

Apart from a well serviced engine, a clean polished hull, good props, correct weight distribution and finding the best balance with trim to speed/rpm, etc ....................
Is there any other ways to improve the fuel efficiency of your boat, adding anything to your fuel or has anyone had there engine remapped/chipped like you can get done on your car?

Your help will be greatly appreciated
Thanks
 
Larson 290 sportscruiser (30 ft)
Twin volvo kad 32's
AVG consumption 2.5mpg

Boat is quite well loaded and quite clean underneath. The figure represents pottering at around 8kts upto cruising at 22kts with the occasional flat out burst.

The boat is new to me & the figure is calculated from the 300 ish miles I've covered in her so far.

At 22kts the engines are at 3200rpm. I've not yet experimented with cruising at higher rpm's to see if consumption improves or gets worse
 
Since fuel burned relates directly to the power generated by the engine, there is no magic way by additive or other to make a drop of fuel deliver any more energy.

The efficiency from burning diesel is higher than that of petrol, but you need a good guess about how much power you demand to be able to calulate the consumption. Of course pulling the full rated hp from en engine is one, but real life mixed use is quite a different matter.

To calculate look here https://en.wikipedia.org/wiki/Brake_specific_fuel_consumption

When looking at grams burned also remember to factor in the density of the fuel in question as 1 kg is not equal to 1 liter.
I believe 0.74 for petrol and 0.88 for diesel are usable factors.
 
Sealine T50, approx half fuel, half water 4 crew.
2 X Volvo D9, 575 Hp
flat out 30/31 knts (once or twice a year) 200 litres per hour so @ 0.68mpg, range 220 ish miles
cruising speed 23 knts, 140 - 150 litres per hour, so about 0.7 to 0.74, sometimes if flat calm 0.76 range 240 ish
pootering 8 - 9 knts from memory @ 25 litres per hour so about 1.5mpg range, 450 ish
slow mode 6 knts 6.4 litres per hour so 4.2 mpg, range 1800 very boring rolly poly miles.
(total fuel consumption)
if its rough, fouled, or fully loaded with everything add 10% to fuel burn.

Only way to save fuel on a mono hull is to go slow. I wouldn´t recommend chipping the engine
Alternatively have a look at catamarans or hydrofoils
 
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Windy 25 with a single 260hp diesel,burns 25 litres per hour at 26 knots.works out to approx 4.7 nautical miles per gallon
 
11M Semi displacement hull.
2 x Perkins M135 135HP engines.
Total fuel burn
@ 5 knots on non tidal river 10L per hour.
@ 8-10 knots tidal average consumption 20L per hour.
@ 12-13 knots. 37 L per hour.
Averaged out over 6 years of ownership.
 
Sealine S23 with a single KAD32 (170hp) on sterndrive.

Over the last 8 years and some 12k miles covered we have averaged pretty consistently 5.4 mpg when worked out as an average over each season which covers a range of cruising from 3 knots plodding along on the canal/river through to 30 knots on the coast.
 
7m Merry Fisher 695 with 175hp outboard - 4 people on board usually, 3/4 fuel, 1/2 water, clean bum..

@6-7kn : 1.2-1.4 NM/l (About 6MPG I think)
@17kn-35kn : 0.8-0.9 NM/l ( About 3.5-4MPG)
 
Ferretti 630 63ft
2 x MAN D2842 LE433 1200hp diesels
1nmpg @ 9.5kts or 0.4nmpg @ 20kts

The only real way to save fuel is to go slower. Speed costs money
 
Itama 14.5 M
Approx 20,000 kg all up -- ( dry 17,000 kg )
Twin - MAN 2876 le 401 - 700 hp. - 13 L - Straight 6
6 knots tick over 18 L /hr @ 600. Rpm
9 knots 36 L / hr --- D speed ---825 rpm
24 knots 150 L/hr ---,1600 rpm
28 knots 180 L / hr Eco -- @ 1780 rpm
30 knot s. 200 L/ hr. cruise 1850 rpm
38 knots 280'L /hr max 2100 rpm
Tankage 2000 L
 
Nimbus 335 Coupé, 10.3m, Semi displacement
Single Volvo Penta D4 260hp shaft drive

Cruising: 2900rpm 17Kn 36L/hr
Pootling (~max displacement speed): 1500rpm, 7Kn 6L/hr

Speed drops with slimey bottom, and increasing load. Note that:
240L diesel (equivalent to half a tank) corresponds to 3 adults on board
80L water (equivalent to 3/4 tank) corresponds to 1 adult on board
 
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