Starting Very Large Engines

[Full Member]

Starting Very Large Engines

I have a technical background but not in heavy engineering (though the subject has fascinated me since boyhood).
For one chapter of my life I lived in Southampton and, working in the Western Docks, used to visit the dry docks to watch maintenance of the cruise ships there.
It never failed to amaze me how the sides of ships would be cut open in order to remove heavy machinery for repair or replacement and then welded back in place once operations were complete.
One of the questions I had but never seemed to get around to posing was "How do you start the ships engine(s) from scratch?"

I assume that smaller engines are first started from batteries which then spin up a fly wheel or similar to store energy and then, when the time comes, a mechanical link (clutch or gearing?) is engaged to turn over and hence start the ship's diesel.

A description from someone in the know would be very much appreciated!

Colin ???

 

[teejay]

Hi Colin-its all done with fresh air mate! Jet engines are usually done the same way but on a smaller scale. Huge air compressors and storage tanks feed compressed air to engine to get it moving, then fuel added at the right moment and away she goes! That's very simplified btw.

 

[martinmartin]

I think they turn them over with compressd air then run on diesel when spinning and when warm enough transfer the fuel to crude oil.Was watching a merlin v10 starting up on youtube couple a days ago and it makes the hairs on the back of your neck stand.

 

[Campervanannie]

My dad was in the Navy for NS then transferred over to the merchant navy and I remember him telling us that his job (before he became a cook) was to feed the donkey as a child I had a vision of a donkey with a bail of hay but no this I believe was a small engine that fed the big engine with fuel.

 

[Deleted member 155]

Even more interesting is that a lot of the engines actually have to be stopped and started up running the other way to go from ahead to astern !
They change over from FFO (f,ing fick oil) to diesel otherwise they can't restart

 

[Deleted member 155]

A guy I used to work with was a chief engineer on a BP tanker he was saying they were slowing down (if my memory serves me correctly ) something like 30 or 40 miles away from where they were mooring and he said about 3 or 4 miles for an emergency stop that would take about 20 minutes !

 

[Full Member]

Thanks teejay, martin martin, Annie and Charlie.
It never fails to amaze me how much there is to learn - no matter how old or experienced one is. All that is required is an inquisitive mind, the ability to accept and admit ignorance - and access to knowledgeable people!

I sincerely hope that I'm able to continue learning.
Thanks again,
Colin ???