Fuel Consumption

[Salty Boy]

Hi I’m considering buying a motor boat powered by two 1000hp Man engines; they have 1850hrs on each, the vessel is 45gt with a deep V hull and 23.32 meters LOA. Anybody out there with an idea on fuel consumption.

 

[davids0865]

I think that the reason you have not had a response is that people will feel that they need a lot more info to offer a sensible opinion, make , model, year, and anything else that you have to hand.

However, to throw some numbers out without qualification, maybe 250 lph at cruise, 50-80 lph at displacement speed.

 

[Bandit]

Gross Tonnage is of no use, that is theoretical wool bale capacity.

What is the loaded displacement of the boat?

 

[Portofino]

Between 350-400 L/h @ fast planning .

Agree with Davids0865 @ D speed 50-80 L/h
Are they V10's cica late 90's ?

 

[drh2]

Sounds like a 'first boat' question.

 

[davids0865]

Sounds like a 'first boat' question.

Probably, 23.32 m loa, about as ambitious as me

 

[Salty Boy]

Yes you are right my first diesel, have been used to petrol guzzling American boats.

 

[Hurricane]

23.32m with 2 x 1000hp - seems a little light on Hp but might depend on the type of boat.
Ours is 20m and 45 tons and we have 2 x 1200hp MTUs

Portofino has the fuel consumption about right.

We always calculate fuel burn at 175 litres per hour per engine at 25 knots (planing)
and
About 25 litres per hour per engine at 10 knots (a tad faster than max displacement speed)

Maybe you would get a little better consumption at the lower (pootling) displacement speed - due to a longer waterline length.

 

[PCUK]

About 80 gallons per hour total at full throttle. Much less when throttled back.

 

[Deleted User YDKXO]

I have a Ferretti 630 weighing 40t with 1200hp MAN V12 engines. With a clean bottom, my boat consumes 110 lph per engine (ie 220 lph total) at 21kts which is equivalent to 0.43 nmpg. At 9kts, each engine consumes 17 lph (ie 34 lph total) to give 1.20 nmpg

For passage planning I work on 0.4 nmpg

 

[MapisM]

Yes you are right my first diesel, have been used to petrol guzzling American boats.

Without knowing either boats, sounds like a pretty radical change anyway. All the best, and welcome to the asylum!
Btw, is the one you are looking at a 1990 Azimut 72, by chance? There aren't many boats around that match your numbers...

 

[Hurricane]

At 9kts, each engine consumes 17 lph (ie 34 lph total) to give 1.20 nmpg

Wow - how do you know these figures, Mike?
Are you slipping into "Pootling" territory?

 

[Deleted User YDKXO]

Wow - how do you know these figures, Mike?
Are you slipping into "Pootling" territory?

I became partial pootle convert last season in Italy when I was shelling out €1.85/litre for diesel when the £ was worth about €1.15. That and the fact that my boat consumes around 460 lph of the stuff at full chat. And you know how it is, Mike. At a certain age, a gentleman doesn't feel the need to rush around at full pelt any more

 

[MapisM]

LOL, naaah, admit it, you're also beginning to appreciate slow cruising lifestyle, regardless of any savings!

The cocktail is simple, after all:
1/3 great spots in crystal clear waters within easy reach;
1/3 good food and beverages;
1/3 (and last but not least!) great company.

Who needs 2 digits speed, when you can enjoy all that?

 

[Deleted User YDKXO]

Who needs 2 digits speed, when you can enjoy all that?

Ah but, its not doing it that counts but knowing that you can do it!