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Old 09-04-2014, 14:57   #61
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Re: Inability to keep the water out > Long distance rescue

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Originally Posted by Cheechako View Post
I bought a good one of these last year. Did a lot of research etc. First time I tried to use it it didnt turn the engine over. Why? Because if your batteries are REALLY dead, they soak up all the amps instead of amperage going to the starter!
Lots of luck starting a diesel engine with the hand drill! haha that's funny...
Connect it to the engine side of the battery switch and switch the batteries off. Switch them back on again when the engine starts. I guess if you have some complex regulation system this could indeed be an issue otherwise the jump pack acts as a load for the voltage regulator until the batteries come back on line.

P.s. a big diesel requires a big stonking unit. I have a "1200 amp" rated unit (which makes no sense to me - but places it mid range) and it kicked over the 33hp fine. I should have mentioned the one time I used it in anger it behaved the same as you have reported until I switched the dead batteries out of circuit. Then it was showtime with no probs.
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Old 09-04-2014, 15:10   #62
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Re: Inability to keep the water out > Long distance rescue

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Must look godawful with exposed screw heads everywhere. And I bet I can grab a wrecking bar and remove what's in the way much much faster than you can pull a whole bunch of screws with a cordless.

No exposed screw heads. All just below the surface. I believe you. I have no doubt you could destroy your interior faster than I could take mine apart. I'll just take a screwdriver to mine when I need access, then screw them back together when done, filling the recess holes with a little goop to keep things pretty.

Speed is not of the essence. You could put gaping holes in both my hulls and she wouldn't go much below the designed waterline. Lots of watertight bulkheads. No need to rush and destroy anything.
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Old 09-04-2014, 15:11   #63
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Re: Inability to keep the water out > Long distance rescue

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What some people used to do for backup, to get the engine running and 'reboot' the electrical storage after a calamity, was to carry an extra wet cell battery with NO acid in it, and carry the acid (at the correct concentration) separately. That will last indefinitely if well sealed. But that is not a trivial thing to arrange safely.
Maybe easier than you would think. Many motorcycle size batteries are shipped and stocked in the store with the acid seperate. These are rather small sized batteries and I am not sure what kind of power it takes to start a diesel exactly but I would guess that you could get a few good cranks out of one of those before it completely died. It could work as an off the shelf, no brainer, one chance backup, they are also rather small and reasonably light so you could even guy two and plan to set them up in paralell for extra power.
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Old 09-04-2014, 15:52   #64
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Re: Inability to keep the water out > Long distance rescue

Someone mentioned cracking an old-school injector if decompressors are not fitted (or two, on a four cylinder engine). Might be worth clarifying:

When mechanics talk of "cracking" a fitting, it means loosening it slightly (as when bleeding a diesel line).

However in ad-hoc decompressing a diesel: If the two hold-down nuts (in most small diesel instances) for an injector housing are loosened, the compression might be sufficient to unseat the injector, but almost certainly not. You will probably have to put a wrench on it and turn it to and fro to free up the sealing interface. Tapping the sides alternately can also help.

(In such instances, it's generally a lot more fruitful and less damaging to tap judiciously with a heavy object than take wild swings with a light one)

This is not ideal. Decompressors ROCK! (and it's not beyond the wit of man to retrofit them to engines lacking them)

.... But ad-hoc 'cracking an injector' to temporarily decompress might well trump being unable to start the diesel and make some impact on water inflow (or whatever you need lots of non-sail power for)

The nuts should be snugged up, by small degrees and in alternation, if the engine starts.

If you have a "modern" engine with electrical injection, hopefully you've sent your regular cheques to the RNLI, though, or paid your taxes

It seems in this brave new world you don't have to worry your head about trying to get things to happen; just push the button, sit back, put on some relaxing music, and wait for the trained professionals. It's their job to know stuff, not ours ....

(sarcasm warning, for the sake of anyone with an irony deficiency)
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Old 09-04-2014, 16:11   #65
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Re: Inability to keep the water out > Long distance rescue

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Originally Posted by Andrew Troup View Post
Someone mentioned cracking an old-school injector if decompressors are not fitted (or two, on a four cylinder engine). Might be worth clarifying:

When mechanics talk of "cracking" a fitting, it means loosening it slightly (as when bleeding a diesel line).

However in ad-hoc decompressing a diesel: if the two (in most small diesel) hold-down nuts are loosened, the compression might be sufficient to unseat the injector, but almost certainly not. You will probably have to put a wrench on it and turn it to and fro to free up the sealing interface. Tapping the sides alternately can also help.

This is not ideal. Decompressors ROCK! (and it's not beyond the wit of man to retrofit them to engines lacking them)

.... But ad-hoc 'cracking an injector' to temporarily decompress might well trump being unable to start the diesel and make some impact on water inflow (or whatever you need lots of non-sail power for)

The nuts should be snugged up, by small degrees and in alternation, if the engine starts.

If you have a "modern" engine with electrical injection, hopefully you've sent your regular cheques to the RNLI, though, or paid your taxes

It seems in this brave new world you don't have to worry your head about trying to get things to happen; just push the button, sit back, put on some relaxing music, and wait for the trained professionals. It's their job to know stuff, not ours ....

(sarcasm warning, for the sake of anyone with an irony deficiency)
i seem to remember that blocking off the air intake untill the engine is cranking fast enough effectively works as a decompressor would on an engine without.
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Old 09-04-2014, 16:19   #66
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Re: Inability to keep the water out > Long distance rescue

It's worth bearing in mind that the ideal, not always achievable, is to be able to start and run the prime mover entirely without electricity. Once salt water has been in an engine room and/or power distribution panel/battery compartments etc in rough conditions, it's quite likely things like starter motors will be temporarily or permanently unavailable.

If you have an engine which strictly needs electricity, that doesn't make you a bad person, and increasingly that's going to be unavoidable. And there are things which can be done to minimise that vulnerability.

I can't see that's a good reason to hose down discussions by people who are not irrevocably in that situation. It's just a different discussion.
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Old 09-04-2014, 16:25   #67
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Re: Inability to keep the water out > Long distance rescue

Andrew's mention of compressed air starting using dive cylinders reminded me of an incident that happened in Nigeria some years ago.
An oldish work boat had blacked out. The crew had not been taking much interest in maintenance, the start air bottles had not been kept topped up, the emergency geny was out of service, and the small hand cranked air compressor which could be used to fill the air start bottle for the generator was seized solid.
So, some bright spark had the idea of connecting a 40 litre oxygen cylinder to the generator engine.
It started with a bang, wrecked the engine and put two people in hospital.
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Old 09-04-2014, 16:26   #68
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Re: Inability to keep the water out > Long distance rescue

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i seem to remember that blocking off the air intake untill the engine is cranking fast enough effectively works as a decompressor would on an engine without.
Just gotta call bs on this one.
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Old 09-04-2014, 16:30   #69
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Re: emergency engine start

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i just put all the sails up,and when i get to 26 knots,just put the 6cylinder in gear and bump start it.....................................

Is there some basis to this myth. I know of one skipper on a twin screw boat that tried to start an engine by going full ahead on the one working engine and then clutching in the shaft on the engine that they were having problems with starting.
Didn't work.
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Old 09-04-2014, 16:32   #70
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Re: Inability to keep the water out > Long distance rescue

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i seem to remember that blocking off the air intake untill the engine is cranking fast enough effectively works as a decompressor would on an engine without.
Good point, some air intakes permit that. (a child sized rubber ball is sometimes recommended)

It's not as free-spinning as genuine decompression, because the engine is trying to pull a vacuum, but I doubt there's a great diff, and for a single cylinder engine it's potentially almost as good as proper decompressor

It is progressively less useful as an engine's number of cylinders increases, because it's "all or nothing".

To start a multicylinder engine with insufficient cranking power, it's necessary to introduce compression to one cylinder at a time.

And you'll need to *keep* cranking vigorously, through the early introductions. At least until the engine pulls away from whatever it is you're cranking with, not just tentatively but with some semblance of conviction. The heat from the cylinders which are compressing and firing will be sucked away into the block around those which are not. I guess it would make sense to recompress the end cylinders first, at least in theory, so they don't have a heat sink on both sides.

If you have time on your side, and the cooker is functioning, draining out the coolant and heating it in a big pan can make a crucial difference. Once the coolant is reintroduced, you'll need to temporarily clamp the bypass hose between where the cooling water enters the block and the thermostat housing (refer the recent thread on thermostats if this doesn't compute)
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Old 09-04-2014, 16:45   #71
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Re: Inability to keep the water out > Long distance rescue

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Originally Posted by nigel1 View Post
Andrew's mention of compressed air starting using dive cylinders reminded me of an incident that happened in Nigeria some years ago.
An oldish work boat had blacked out. The crew had not been taking much interest in maintenance, the start air bottles had not been kept topped up, the emergency genny was out of service, and the small hand cranked air compressor which could be used to fill the air start bottle for the generator was seized solid.
So, some bright spark had the idea of connecting a 40 litre oxygen cylinder to the generator engine.
It started with a bang, wrecked the engine and put two people in hospital.
That's yet another great story, Nigel. You HAVE to write a book!

I found myself transported back in time, you know the feeling? ... A colleague of mine was at a smelter in Barhain, directing the installation a plant our company had designed and built for handling aluminium extrusion billets (continuously cast into a pit, twenty tons of 6m long 'wind chimes' in each pour).

He wondered why the prime contractor (Bechtel Pacific, IIRC) was SO anal about subbies supplying all their own services. Everyone had to bring mobile gensets, compressors, and yadda.

Then one day he noticed a strange odour. The local contractors nearby were attempting to use a pavement breaker. They were puzzled that it was reciprocating in an uncharacteristically anemic and desultory way...

Turned out they had sneakily hooked it up to the 'shop air' to save having to hire a big-arse compressor at penal rates.

Except they had misinterpreted the colour codes and were trying to run from the LPG mains.


Safer than oxygen, though ... that's SERIOUSLY scary !
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Old 09-04-2014, 16:49   #72
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Re: Inability to keep the water out > Long distance rescue

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Just gotta call bs on this one.
"Calling bs" (at least on this forum) seems to be code for

"Jeez - why didn't I think of that!"

I wish people would say what they meant... it's so confusing this way
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Old 09-04-2014, 16:54   #73
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Re: emergency engine start

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Is there some basis to this myth. I know of one skipper on a twin screw boat that tried to start an engine by going full ahead on the one working engine and then clutching in the shaft on the engine that they were having problems with starting.
Didn't work.
If they *were* able to attain 26 knots on one donk (and had a VP prop wound to > 45 degrees on the dead'un) I can imagine it might work...
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Old 09-04-2014, 16:54   #74
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Re: Inability to keep the water out > Long distance rescue

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Just gotta call bs on this one.
i read it on Cruisers Forum so its got to be true!

thinking about it the reference was probably to STOPPING an engine without a decompressor,sorry just woke up.
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Old 09-04-2014, 16:59   #75
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Re: Inability to keep the water out > Long distance rescue

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My experience has been entirely different, although I was skeptical until seeing them in used during a 4wd trip out in the desert which convinced me they have value. You do need a unit with the correct rating for the engine and keep it trickle charging at all times. I have used mine to start the boat's engine when we first brought the boat with it's dead as a dodo batteries, but I don't bother with it onboard with the good batteries. For long term cruising I'd roll my own inbuilt unit if I really thought there was a chance of total house bank failure.
I too was skeptical - until I ran down the big battery on a borrowed SUV. A guy with a Nissan Patrol, with dual batteries, wasn't able to jump start me, so when the guy from the AA arrived with this toy portable unit, I was privately thinking "no way, Jose"

Bugger me if it didn't start instantly ! The 'toy' unit was from Switzerland. The guy reckoned he only had to recharge it, at most, a couple of times a week, despite using it constantly. Seems too good to be true, to me.
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