Urgent help needed to recover abandoned yacht NW Barbados

[MarkJ]

Originally Posted by masonc

A diesel at idle without load is going to run for an awfully long time on full tanks, as long as everything was setup right. The batteries won't last long if the fridge was on, if you ever get in that position turn off the fridge and any other large load.
If the only load was a electronics and there was a solar panel, it could run indefinitely. My boat has a wind turbine and two small panels, it can run forever without engine, even with the fridge on.
So, it's all about how long the engine ran for. Easy to calculate if we know the engine, the fuel tank capacity without human involvement.

It's a long thread to have to read back.

Engine is out of fuel long ago.

No solar, no wind, nothing on except AIS and ignition key.

[accomplice]

Originally Posted by Exile

Do most people run their bilge blowers the entire time their (diesel) engine is running? Do we know for certain that AWW had his running when he left the boat?

Our engine room exhaust fan is thermostatically controlled. It is one less thing I need to think about.


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[Exile]

Originally Posted by MarkJ

It's a long thread to have to read back.

Engine is out of fuel long ago.

No solar, no wind, nothing on except AIS and ignition key.

I looked up one of the popular AIS transponder units -- the Vesper 850 which has its own display -- and the spec'd power consumption was 3 watts nominal. So that would be 0.25 amps. The Vesper XB 6000 -- no display & no wifi -- is spec'd at 2.5W nominal or closer to 0.2 amps.

Can't help with the ignition key and its potential draw on the house bank through the alternator, etc., but hopefully one of the more electrical-savvy posters can chime in. Best case would be no house bank alternator in which case ignition key would only draw on engine start bank (assuming there are separate banks). Seems a lot of bigger boats like the OP's have two alternators charging separate banks, or one large alternator charging one large bank that serves as both house & engine start.

[Exile]

Originally Posted by Scout 30

with a diesel there is no safety advantage to running a blower when the motor is running. The only reason to run it with the motor is to reduce temps in the engine room.

This is what I always assumed so wind up not running the blower very often.

[Scout 30]

Sounds like a lot more info from the PO is needed in order to estimate the current state of the batteries. Just leaving the blower on would have done them in. If the running lights are incandescent that would be another big one. Maybe he could post what exactly was left on in as much detail as possible.

[Snore]

Originally Posted by MarkJ

He doesn't know. The boat is new to him.



Nav lights were not on.



So it all depends on the drain on the house bank while the ignition key is on but the engine stopped for lack of fuel.



400 amp hour bank.



Guesses?

Mark unless it has an A, B, AB switch the batteries are likely dead. Battery combiners usually only combine he batteries if there is a charge (voltage >+/-12.8).

If the engine was "just ticking over" the alternator was probably not putting out a lot. So unless the A B switch was on A+B the batteries would probably not get a big charge.

All that said truly hope the OP finds the boat. But he made the right call. He got everyone off safe and sound.

[a64pilot]

I stupidly left a little Bulldozer running all weekend, I don't know how many more days it would have idled as it was really slobbering, fuel doesn't really burn off at idle and it builds up over time and slobbers.
Anyway best I can remember it burned almost no fuel at all, not enough to drop the tank level a whole lot.
Anybody have any idea as to fuel consumption at idle?

[jcapo]

Originally Posted by a64pilot

Anybody have any idea as to fuel consumption at idle?

I believe the accepted figure for a diesel engine is .055 gallons per hour per HP.

[Fence Man]

Nothing scientific, but it's cold enough here that I've kept a truck running all week. I know it was filled up Tuesday, and was driven to the job site every day...about 60 miles round trip. It hasn't been shut off, and still has over half a tank. Diesels burn next to nothing at idle. (The old ones anyway. All this new DPF jazz is a load of crap.) I wouldn't be surprised if that little motor used less than a couple gallons a day at idle.

Edit: A little more relevant is my post driver. 100HP Yanmar 4 cylinder diesel. 13 gallon tank lasts me two good working days, and I usually run it about 1/2 throttle. That would be under load full time with my open center hydraulic setup. So long as a boat is in neutral, the only load will be the alternator and water pump. I'll bet a beer that engine is still ticking.

[Tricolor]

For small modern diesel engines we calculate with an idle burnrate of 0,5 liter per hour per 1000 cc engine volume.

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[transmitterdan]

Originally Posted by jcapo

I believe the accepted figure for a diesel engine is .055 gallons per hour per HP.

At idle the HP is tiny so this estimate isn't very accurate.

[Alastair A]

Idle rate of fuel consumption would assume gears in neutral (no drive power). I trust this was the situation at emergency abandon. Best wishes for the OP and thanks for all CF interested and assisting. Cheers A.

[MarkJ]

Owner says 110 litres of fuel in the tank. That's 25 gallons.
It's now 17 days so it's definitely run out.
Say it ran .5 litre per hour (1 pint per hour) then it ran out 8 days ago.

400 amp hours batteries.
No nav lights we on.
Nothing was on, ie EVERYTHING WAS OFF except the AIS and the ignition switch.
If there's absolutely no loss in the boats general wiring and the key on gives no loss then the only drain is .25 amp then the AIS is still on.

But, my boat has a general wiring loss when everything is off or about .5 amp. So total .75 amp the AIS may still be on.

Any higher loss or usage the battery must be dead, the AIS must be off.

I can't believe someone could turn everything off while abandoning ship. I wouldn't have the presence of mind.

[Alastair A]

Thanks Mark. Your guidance and care with this is golden. Best wishes for all. A

[Exile]

Originally Posted by MarkJ

Owner says 110 litres of fuel in the tank. That's 25 gallons.
It's now 17 days so it's definitely run out.
Say it ran .5 litre per hour (1 pint per hour) then it ran out 8 days ago.

400 amp hours batteries.
No nav lights we on.
Nothing was on, ie EVERYTHING WAS OFF except the AIS and the ignition switch.
If there's absolutely no loss in the boats general wiring and the key on gives no loss then the only drain is .25 amp then the AIS is still on.

But, my boat has a general wiring loss when everything is off or about .5 amp. So total .75 amp the AIS may still be on.

Any higher loss or usage the battery must be dead, the AIS must be off.

I can't believe someone could turn everything off while abandoning ship. I wouldn't have the presence of mind.

I doubt I would either. Then there's the occasional, usually hard-wired bilge pump turning on, possible CO and smoke/fire detector(s), and battery self-discharge. Maybe minimal loads, but lots of variables and several unknowns. Unless the owner has more info, maybe all you can do in contemplating some sort of search is start by assuming the best case scenario and working backwards based on estimated miles of drift/day. Seems like a tall order but if resources can be safely & affordably mustered then why not? Had no idea that Class B won't leave as reliable a satellite track as Class A.