Beneteau Antares 30 Fly fuel consumption

[PhilSam]

I am currently looking at an Antares 30 Fly and wondered if anyone had an idea of the fuel consumption I can expect at say 9 knots and 18 knots.
It has a Volvo Penta D6 engine (370hp)
Thanks
phil

 

[PaulRainbow]

At 18 knots, about 40 litres an hour at a guess. 9 knots is not a speed you're likely to be able to cruise at, it's too fast for hull speed and too slow to plane.

I suspect if you ask the question on the motorboat forum someone with an Antares will reply with some more accurate information.

 

[john_morris_uk]

I am currently looking at an Antares 30 Fly and wondered if anyone had an idea of the fuel consumption I can expect at say 9 knots and 18 knots.
It has a Volvo Penta D6 engine (370hp)
Thanks
phil

Phil, I’ve moved this here so hopefully you’ll get more replies.

 

[ChromeDome]

I don't own an Antares (mine is a, twin Nanni 175 hp, Ocqueteau 975 with a hull similar to Antares and the other Beneteau sibling, Merry Fisher 925 - allegedly infusion moulded by Beneteau as the smaller Ocqueteau yard didn't have the facilities for the size). The Antares 30 hull has been updated between versions and of course, single vs twin props need different hull arrangements (two prop tunnels will help going straight at low speed, single versions have a tad more keel so probably not too different in this respect).

The consumption logic is that you have to feed the horses you put to work. If your ready-to-go GW and the weather & sea conditions require e.g. 300 hp to go at your desired speed, the fuel burned will be as much as needed to produce the power. The D6 will burn some 80 liters per hour at full throttle, so the big question is how much power you will demand?

You can play with it here:
Volvo Penta Diesel | D6 370 & D6 435 | 370 / 435 hp | Fuel Consumption - Liters per hour

Hull speed or displacement speed is the speed at which the wavelength of a vessel's bow wave is equal to the waterline length of the vessel. As boat speed increases from rest, the wavelength of the bow wave increases, and usually its crest-to-trough dimension (height) increases as well.

By hull speed calculation for the Antares' Length in Waterline (LWL) of 9.98 m (?), the optimal speed (lowest consumption) at displacement is 7.66 knots.
Hull Speed Calculator | Boat Displacement Speed Calculation

Any higher speed that takes power to hold the boat at a less than planing angle will use power for this instead of moving the boat forward. Therefore, the next 'economical' speed is at the lowest rpm where the boat is on a stable plane (achieved by full throttle until it planes, then back off as much as possible while keeping it planing, utilizing trim flaps if fitted).

While this is true you however also need to factor in other aspects, including but not limited to:

- Only engine hours burn fuel. All the hours spent on board at anchor or in the marina will burn nothing.
- Weather and sea condition may decide the actual speed - you may need/want to keep the bow high to get a better ride in a chop.
- When cruising in company with fellow boaters the agreed speed may not be your desired 7.7 knots.

 

[Elessar]

I am currently looking at an Antares 30 Fly and wondered if anyone had an idea of the fuel consumption I can expect at say 9 knots and 18 knots.
It has a Volvo Penta D6 engine (370hp)
Thanks
phil

One of my favourite boats. Really good sea boat.
They really need a stern thruster though as the prop walk is significant. If it hasn’t got one budget for one.
Paul Shotton will fit one for you if the boat is in the Solent.

On a 30 ft boat 9 knots is not a good speed and will probably use as much fuel *(or maybe even more) than 18. 7 will be way more economical and 6 even more so. But the D6s have real time fuel burn read outs so you can figure the economy at various speeds easily.

*edit I mean fuel per mile not fuel per hour. Litres/mile the only useful measure IMO litres/hour is for jet skis.

edit 2 just read ChrisDome‘s useful hull speed explanation. Can’t find an LWL for this boat but I’d guess a metre less than the hull length of 9.98 m so his 7.66 knots is a bit high but the principle is right.

 

[Elessar]

Duplicate in error

 

[Elessar]

I don't own an Antares (mine is a, twin Nanni 175 hp, Ocqueteau 975 with a hull similar to Antares and the other Beneteau sibling, Merry Fisher 925 - allegedly infusion moulded by Beneteau as the smaller Ocqueteau yard didn't have the facilities for the size). The Antares 30 hull has been updated between versions and of course, single vs twin props need different hull arrangements (two prop tunnels will help going straight at low speed, single versions have a tad more keel so probably not too different in this respect).

The consumption logic is that you have to feed the horses you put to work. If your ready-to-go GW and the weather & sea conditions require e.g. 300 hp to go at your desired speed, the fuel burned will be as much as needed to produce the power. The D6 will burn some 80 liters per hour at full throttle, so the big question is how much power you will demand?

You can play with it here:
Volvo Penta Diesel | D6 370 & D6 435 | 370 / 435 hp | Fuel Consumption - Liters per hour



By hull speed calculation for the Antares' Length in Waterline (LWL) of 9.98 m (?), the optimal speed (lowest consumption) at displacement is 7.66 knots.
Hull Speed Calculator | Boat Displacement Speed Calculation

Any higher speed that takes power to hold the boat at a less than planing angle will use power for this instead of moving the boat forward. Therefore, the next 'economical' speed is at the lowest rpm where the boat is on a stable plane (achieved by full throttle until it planes, then back off as much as possible while keeping it planing, utilizing trim flaps if fitted).

While this is true you however also need to factor in other aspects, including but not limited to:

- Only engine hours burn fuel. All the hours spent on board at anchor or in the marina will burn nothing.
- Weather and sea condition may decide the actual speed - you may need/want to keep the bow high to get a better ride in a chop.
- When cruising in company with fellow boaters the agreed speed may not be your desired 7.7 knots.

great calculator thank you!

I now know my LWL is a full 3m less than my LOA and my hull speed is 8.0901! I always worked on 7.5 so that’s good to know.

 

[PhilSam]

At 18 knots, about 40 litres an hour at a guess. 9 knots is not a speed you're likely to be able to cruise at, it's too fast for hull speed and too slow to plane.

I suspect if you ask the question on the motorboat forum someone with an Antares will reply with some more accurate information.

Thanks for your reply, very helpful

 

[baldyash]

I have a Antares 30 and can only comment at its cruising speed of19 knots. Clean bum 52 lph ish. By autumn 60 ish. Flat out 25/26 knots and clean bum, 72 ish

 

[PhilSam]

I have a Antares 30 and can only comment at its cruising speed of19 knots. Clean bum 52 lph ish. By autumn 60 ish. Flat out 25/26 knots and clean bum, 72 ish

Thanks Baldyash, that’s very helpful. Sea trial soon which will be interesting.

 

[Elessar]

I have a Antares 30 and can only comment at its cruising speed of19 knots. Clean bum 52 lph ish. By autumn 60 ish. Flat out 25/26 knots and clean bum, 72 ish

It’s not a jet ski!