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Old 26 September 2011, 08:47   #1
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Can you Solve this Mystery.........

Some of you maybe aware I recently made a crossing to Braye on Alderney from Langstone. What should of been a straight forward crossing turned into an epic 10 hour struggle which eventually seen me run out of fuel and have to be rescued by the French coastguard.
So here is where the riddle begins.
On the return leg, conditions flat calm and for the first hour or so we had a flowing tide pushing us along.
  • Boat - Humber Ocean Pro 6.3m
  • Engine - HOnda Vtec 150hp
  • Crew - 5 Blokes average 90KG per person
  • Kit - 3 x Dive Kit (30kg Each)
  • Fuel - 260l - (260KG)
  • Camping Gear - 50kg
  • Life Raft - 45kg

My boat set up has an internal tank of 160l and 2 External tanks (25l each) with a direct feed into the fuel system.
WE set off with the intention of keeping the boat to about 4000rpm and constant on a direct track (anyone deviates 500m from the track were sacked as skipper).
I had the fuel switch set to draw down on main and the hose was connected to the first 25l. After about 3 hours running across the channel the engine died which indicated the fuel had gone, i then went to move the fuel switch and noticed it was slightly off centre, I moved to all the way to external and tried to start the engine, nothing. Checked the 25l tank and it was empty, so scratching our heads, had teh fuel in this tank leaked out, but surely we would smell 25l of unleaded swooshing in the boat. Anyways swapped the pipe over to the other 25l and siphoned 50l of reserve fuel from 2 jerry cans into the main tank.
So in theory now I have 75l left (50 in the main and 25)
We run the engine and of course we can see home so the engine is flat out and we are doing 28 knots WOT.
External tank runs out and we switch back to main and run that for about another hour which really should be taking it down to about 20l left.
Heres where it gets confusing.
I took the boat out for a trip up the Hamble yesterday and went to fill the engine. Expecting to put in about 140l. But it would only take 50l which indicated 110l left over, which to me is impossible as I only put 50 in after it ran out at sea.
So I couldnt understand how going to Alderney i managed to get through 210l and still run out. Its only 82miles
On the return I actually then only used 150l which is more realistic as we were gunning it.
SO I suppose the question is - how did I end up with 110l after only dropping in 50 on an empty tank?
All suggestions appreciated

Rob
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Old 26 September 2011, 10:17   #2
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Syphoning from the 25l tank back to the main tank the sucking air as the 25l tanks emptyed into the main perhaps?
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Old 26 September 2011, 10:23   #3
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Rob, Sounds like an exciting trip! At least you all made it back intact.

Is it possible that the fuel pick up pipe in the main tank has become dislodged/moved so you can't get the last 60L out?
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Old 26 September 2011, 10:34   #4
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Polwart's suggestion is the only plausible thing I can come up with too.

How much did the French charge you for the privilege of being recued?
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Old 26 September 2011, 11:38   #5
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How about the trim or angle of the boat with weight distibution effecting the pick up pipe.
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Old 26 September 2011, 12:14   #6
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Well I have 2 thoughts
1) as the connector wasnt quite in the position for the main tank, the engine somehow managed to draw down on the 25l and at least 50l from the main. Which in theory is about 3/4 hours cruising. I then topped up with the 50l spare which actually refilled the tank complete.
or
2) I managed to get 3 hours and about 60 miles from 25l (the little external tank) and somehow lost some fuel from the main

How much did it cost for the Coasty - well they lightened my wallet to the tune of 320 Euros.

I actually filmed the events here

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Old 26 September 2011, 13:08   #7
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according to your list you have 260l - according to the tank figures you only have 210l I assume that the list is wrong?

do you have a dipstick for the tank? might be interesting to try again, but dip tank... would confirm theory about not picking up xx last litres...

I would try nearer to land and with a spare tank or two on board though

if only 1nm away - do you have oars? you should have put the crew to work!

Alasdair
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Old 26 September 2011, 15:02   #8
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I went out with 210l but not wanting to make the same mistake on the return leg I then purchased two cheap 25l jerry cans and filled them.

The tank is undert the console and all sealed in so I cannot get to it, but i did go out last night up the Hamble and only ran the main tank, so now when I fill it I will get a feel for the fuel consumption
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Old 26 September 2011, 15:39   #9
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With hindsight my biggest regret of the nite was that I didnt use the oars to row in, as you can see from the video 2 of the crew were in melt down and wanted a helicopter to come save them, I was just annoyed that we could see the lights of Cherbourg but sadly was dead in the water.

Next time I go out with the lads I am going to do a row exercise to just see how hard it would be - would of saved me a ton of cash
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Old 26 September 2011, 16:05   #10
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Quote:
Originally Posted by Polwart View Post
Is it possible that the fuel pick up pipe in the main tank has become dislodged/moved so you can't get the last 60L out?
Pictures attached from the build thread show that the pick up is at the bottom of the tank so a dilodged pipe is unlikley

Is it possible that when you fill the tank the air can not get out of the tank fast enough, so blows fuel out of the filler making you think that the tank is full when it is not, so is it possible that you didn't start with 160l in the main tank?
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