2008 PHANTOM 50 FUEL BURN?

[John100156]

I am planning a trip to assist in bringing a Fairline Phantom-50 back from Portals-Mallorca to San Pedro-Spain in a couple of weeks time, approximately 200nm.

The boat runs Volvo D12's (715hp) with a cruising speed of 25kn and top end around 33kn, we achieved 31.7kn WoT on a recent sea trial with broker, engines were running very well.

I have requested approximate fuel burn figures at cruising speed from the broker/owner, but nothing back as yet. I am guestimating say 7L/nm or say 175L/Hr.

Can anyone assist with a better estimate that has a similar boat/spec?

The full tank capacity is perfectly sufficient at 1,980L but good to get some idea before departing.

We can refuel easily in Ibiza or Formentera if tanks are not full when departing, not sure whether to go West or East of Ibiza at the moment, will depend on prevailing wind/weather at the time. Done similar trips before.

Any comments welcome of course!

 

[madabouttheboat]

My experience of a 50ft shaft driven flybridge was that, on the plane in the low 20's, it achieved around 0.6-0.7nm per gallon. That equates to somewhere in the region of 150-160lph. This was with smaller D9's, but they would have been working harder than your D12s so I would expect something very similar.

 

[volvopaul]

If the seas are rough you will be near 10 litres a mile .

 

[Portofino]

What % load were you running @25 knots .What rpm , what’s the wot anyhow out of curiosity?

It depends on that the fuel burn , which is related to drag ( fouling) and displacement, how much crap it’s accumulated.
As 2000 L is near enough 2 tons so it will burn more @25 knots on full tanks than under 1/2 .
I would say my 12.8 in-line 6 s at 1800 rm do 95 L side .1750 85 L a side .

The speeds irrelevant as it just a factor of the drag / weight .Higher than yours FWIW but you are enquiring about fuel burn .

For safety figure 180 L hr in your deliberations.

 

[John100156]

Thanks for comments so far, happy to receive further.... Awaiting weather and report on oil(s) back from Volvo Labs before we get the green light (the samples were taken to a main dealer in Sant Carles, thanks to Volvopaul for his advice in that regard).

Tanks were 3/4 full on the sea trial, with 50% water (say 280L) on board and with three people, so other than fuel, fairly lightly loaded.

SOG 23.3kts @1900rpm - wide open throttle (WoT) the boat achieved 31.7kts, only run at that speed for 5-10 mins, with more time and better trimming may have achieved the maximum advertised 33kts.

Very clean bottom, recentl;y AF'd with shafts, props and rudders, etc., all very clean.

Sea state and wind was favourable coming out of Santa Ponca on our trip back to Portals, where the boat is now. F1-2 at best.

I guestimated an average 175LPH which I think is a safe bet as the boat will lighten, which at 25kts will take say 8 hours including a slow run in at the end and equates to a burn of say 1400L, or with Porto's 180LPH, 1440L, so a fairly healthy 500+L in reserve should suffice. Fill tanks before departure and again when in San Pedro and will report back actual burn and conditions following that trip.

 

[NBs]

Hi,

indicative test, boat 50 Squadron

Fairline Squadron 50

 

[Hurricane]

(the samples were taken to a main dealer in Sant Carles, thanks to Volvopaul for his advice in that regard).

And the oil sample delivery agent!!

I would think that 7l/mile is close but might be a bit on the light side.

 

[Portofino]

Hi,

indicative test, boat 50 Squadron

Fairline Squadron 50

That’s not a “2008 ……. “

 

[DPH]

On my 50 with D12s I think the best economy was 1750 rpm which was 22/23 knots and about 150lph combined.

 

[Andrew M]

I thnk you're in the right area. Pearl 60, D12 800's, WOT on a clean bottom she'll top out at 33knts and burning about 180 lph per engine, can't remember the exact cruising number so will try and find photos of helm with the burn rate showing......

 

[SC35]

Generic figures for one D12-715
Not specific to any actual boat.

 

[jfm]

8.5 litres/nm averaged across the trip is about right for your situ and slightly conservative.
(Plus 5 litres/hour for generator)

 

[John100156]

Thanks chaps for your replies, all very informative.

Broker has advised the boat should be ready on Friday, following rectification of minor defects picked up on the survey.

Initial passage plan/WPs completed, looking good to go west of Ibiza typically slowish out, cruise in the middle and slow in. So one day to refuel and prep, and then off at first light next day, just awaiting confirmation tomorrow before booking flights to PMI (Becoming more expensive by the day)!

There is a weather slot over the w/e which will give us a reasonable push up the b*m, but too early to say for sure at the moment, I have found forecasts over recent months to be a bit erratic, using Windy and Passage Weather. We shall see....

Thanks again for all the help and advice!

 

[John100156]

And the oil sample delivery agent!!

I would think that 7l/mile is close but might be a bit on the light side.

Tallers Cornet - I arranged with Pau and gave them to Nick - should have results back shortly.

 

[John100156]

8.5 litres/nm averaged across the trip is about right for your situ and slightly conservative.
(Plus 5 litres/hour for generator)

No Genny on John, none of the fairer sex on board, and lets face it, its not that hot in the Med at the moment is it......

 

[Hurricane]

I have found forecasts over recent months to be a bit erratic, using Windy and Passage Weather. We shall see....

This year, I found Windy very good - I've even subscribed.

One of the best modes in Windy is the "Waves" section.
Select Waves
Click a point on the map
Click the little down arrow on the selected point
And you get a display like this:-



Those three little arrows tell you everything.
Two different swells (Green and Orange) and the wind (Light Blue).
The swell is probably our biggest concern
For us when we made our crossing last week (not the above image), the orange swell was from behind and the green swell was being generated by wind (the Light Blue arrow).
Even though we had 1m swell, the biggest one was from behind which made our crossing bearable.

Once set up, you can reposition the point and time to see how it will affect you.
You can also change the model with a single click - I only really use ECMWF and the GPS models.
You might be able to see in the above pic that I'm logged in as a Premium user which gives me a time resolution of 1hr.
But you can do most of this using the free (unregistered) version.

 

[John100156]

Yes I subscribe to Windy Premium and have found it very useful; we have a slot on Sunday, but Monday is now looking even better, there is no rush, we fly out to arrive Portals Nous around lunchtime on Friday......

 

[Hurricane]

Yes I subscribe to Windy Premium and have found it very useful; we have a slot on Sunday, but Monday is now looking even better, there is no rush, we fly out to arrive Portals Nous around lunchtime on Friday......

?loody hot out here at the moment, John.
Thank god I have a good A/C engineer!!!

 

[PowerYachtBlog]

Most flybridges in that size and with engines of 12 litres (about 700hp) capacity you are looking at 7 to 8 litre per nm.

 

[MapisM]

The speeds irrelevant as it just a factor of the drag / weight.
Higher than yours FWIW but you are enquiring about fuel burn.

It's exactly because he's enquiring about fuel burn that speed is VERY relevant.
Measuring fuel burn in l/hr is just an old habit, but actually meaningless.
When talking of fuel burn, it's only l/nm what really matters.
In fact, modern instruments capable of measuring fuel burn in real time take also speed into account and give you directly the l/nm (as well as residual range) without bothering to do the math.

Back to the point, even without any first hand experience on the P50, I tend to agree with PYB comment.
More than 8 l/nm would be rather inefficient for the size/type of boat, unless triggered by dirty bottom/props or any other problem.
FWIW, I burn 7 l/nm at low cruise (18/20 kts) with my rather heavy and beamy 56' (with 15L/800hp engines), and even at 25/26 kts I'm still within 8 l/nm.