Why I like boating on the SoF

Great, very calm, I need a port tonight , tried Antibes, no luck so I’m about to contact Cannes and then if no luck maybe Nice.
Ha … as least with the duff weather we seem to be able to find marinas easy & cheapER fuel in uk. Weymouth booked weeks ago AND not raining (well at least for now), ok view not quite so good 😬
 

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Holey moley. It’s about £1.10 in the Uk at the moment, a bit more if you don’t do the 60/40 thing.
It was a bit of a shock seeing Aquaholic's video of him filling up at £1.40ish and looking at the price at the local cheap filling station for the car was €1.87 (£1.60) for diseasel, it's normally a lot cheaper for diesel here than in the UK, petrol was over €2.00 per litre.

Oh, in Sunny Belgium it has gone back to rain and a thunder storm has just passed over, it added a bit of a dramatic touch to my VHF SRC practice for distress calls this morning :)
 
Surely be way less than that? 80-90 more like I would have thought
Given the high cost of fuel, this year I've been experimenting a bit more with different speeds to see what the real consumption is with clean bottom, stern gear, etc. It's really interesting to see how speed and revs affect, or more importantly for me, don't affect the consumption. In litres per nautical mile, I achieve the following with my Sunseeker P57 and two D13-900s. The boat is almost always quite "heavy" with full fuel and water tanks, Williams 345 tender, water maker and it's fitted with the less dynamically efficient fin stabilisers.

8 knots - 4.0 l/nm
9 knots - 5.0 l/nm
10 knots - 6.0 l/nm
12 knots - 8.5 l/nm
14 knots - 10.0 l/nm
20 knots - 10.5 l/nm
25 knots - 11.0 l/nm
30 knots - 11.5 l/nm

The conclusion is that once you are above 14 knots or so, any further increase in speed makes very little difference to the fuel consumption per mile. You can choose the cruising speed based on comfort, conditions and looking after your engines without worrying about additional fuel burn.

The most economical speed is around 8 knots ... at this speed, I have a range of about 500 nm with a 10-15% reserve.
 
Very interesting numbers
I see that for a boat of that size you do not suffer at all of the transition from displacement to planing

On my small v39, I am super efficient at either 8-9 knots (2.2-2.8 l/nm) or above 24 knots, where consumption is stable in the range 3.5-3.8 l/nm.

Anything in between and the efficiency is killed.
At 9.5 knots I have same efficiency as 24 knots and above. This is the upper limit of displacement speed.

Best efficiency is at 27 knots at 2.900rpm with 3.5-3.6 l/nm.
 
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Given the high cost of fuel, this year I've been experimenting a bit more with different speeds to see what the real consumption is with clean bottom, stern gear, etc. It's really interesting to see how speed and revs affect, or more importantly for me, don't affect the consumption. In litres per nautical mile, I achieve the following with my Sunseeker P57 and two D13-900s. The boat is almost always quite "heavy" with full fuel and water tanks, Williams 345 tender, water maker and it's fitted with the less dynamically efficient fin stabilisers.

8 knots - 4.0 l/nm
9 knots - 5.0 l/nm
10 knots - 6.0 l/nm
12 knots - 8.5 l/nm
14 knots - 10.0 l/nm
20 knots - 10.5 l/nm
25 knots - 11.0 l/nm
30 knots - 11.5 l/nm

The conclusion is that once you are above 14 knots or so, any further increase in speed makes very little difference to the fuel consumption per mile. You can choose the cruising speed based on comfort, conditions and looking after your engines without worrying about additional fuel burn.

The most economical speed is around 8 knots ... at this speed, I have a range of about 500 nm with a 10-15% reserve.
All I can say is - ouch !

I get 1.8 litre per NM at 28 knots! I know our boats are not really comparable, but ouch again
 
Our anchorage today .It’s mad with Italian families obviously as there last week closes .
Fuel .Yes there‘ s not much in it for short trips .This island is 8 miles from our marina .
D speed @ 9.6 knots 890 rpm gobbles 20/21L hr and the plotter says approx 45 mins to run .
So 3/4 of 40 = 30 L each way .
P speed say 1780 rpm it cruises at 75 % load @ 29 knots , plotter says something like 12 or maybe 15 mins ? Burn rate is 85 L or 170 L for the boat .
So 1/4 that ( 15 mins / hr ) = about 44.5 L .

For a 15 L difference it’s not worth pissing about @ D. If it’s 12 mins that diff is lower .

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