# Confused.



## waldziu (Jun 17, 2008)

http://www.theengineer.co.uk/blog/queen-elizabeth-takes-its-bow/1003401.article.

Looking at the picture of the enineer working on a diesel engine, has me comfused. Have diesel engines chanches so much. 

To an old stoker and one who has carried out a couple of gas tubine changes.

It looks to me like a GT.


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## clevewyn (May 16, 2010)

Even worse the guy blogging " is responsible for all the engineering work being carried out on the QE Class programme."

Clearly a gas turbine, that being said they run on diesel or the ones I encountered did so I guess they are a diesel engine (sort of).

The QE class according to BAE specs has 2 GTs and 4 Diesels to generate electricity for the propulsion.

I take it when they say diesels they mean the ones with lots of pistons going up and down.


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## chadburn (Jun 2, 2008)

Chambers has Diesel Engine, " An internal combustion engine in which heavy oil is ignited by heat generated by compression"


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## waldziu (Jun 17, 2008)

Clevewyn, you are correct as I shuold have known ergo GTs are therefor diesel engines.
The marine type not the aviation type.


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## doncontrols (Feb 17, 2007)

Aaaaah, but the GT will not ignite the diesel by virtue of its own compression. It is lit off by spark plug and it is subsequently maintained by flame propagation, regardless of the fuel. So it is not really a diesl engine. Still conforms to 'suck, squeeze, bang, blow' though!!
Cheers, Don.


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## cryan (Jan 8, 2007)

The GT is not a diesel engine, the diesel engine is the compresion ignition engine designed by Rudolf Diesel. Incidently the Gas Turbine does not burn Diesel, it burns in the case of ships, Marine Gas Oil. Diesel Fuel is slang for the tax code DERV or Diesel Engined Road Vehicle which again refers to the engine of Rudolf Diesels design.
So basically your right the caption is wrong.


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## Jeff Taylor (Oct 13, 2006)

So, a possibly stupid question; is marine gas oil basically #2 diesel/fuel oil, or something vastly different?


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## waldziu (Jun 17, 2008)

In the Navy (I feel a song coming on) we were excempt tax and at only 56p a gallon 4.54609 litres to the mitricated (sp deliberate) in 1982.


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## surfaceblow (Jan 16, 2008)

The numbering system to order Marine Fuels have been changed. While I been using the numbering system of 1 to 6 and letters A to C. In my later years on ships I also used the terms MGO, Navy Special, F76, IFO 180, 380 and HFO but these have been succeeded by ISO specifications for Marine Distillate Fuels ISO-F-DMX, DMA, DMB and DMC. The marine residual fuels are ISO-F-RMA 30, RMB 30, RMD 80, RME 80, RMF 80, RMG 380, RMH 380, RMK 380, RMH 700, and RMK 700.

Also confused.


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## clevewyn (May 16, 2010)

All to technical for a humble stoker, the only fuels they know about are FFO, Diesel and Grog(?HUH)


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## chadburn (Jun 2, 2008)

There have been G.T's driven by Diesel piston "engine's" in the past and the vessel's were listed as being Gas Turbine powered(Eat) The "picture" painted of the economic virtue of one them was illustrated by a white elephant.


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## waldziu (Jun 17, 2008)

clevewyn said:


> All to technical for a humble stoker, the only fuels they know about are FFO, Diesel and Grog(?HUH)



Don't forget OEP69, OMD112 and of course many (Pint)(Pint)(Pint)


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## Billieboy (May 18, 2009)

chadburn said:


> There have been G.T's driven by Diesel piston "engine's" in the past and the vessel's were listed as being Gas Turbine powered(Eat) The "picture" painted of the economic virtue of one them was illustrated by a white elephant.


I've forgotten the name of the ship(s?), but I thought that they were referred to as, "Free Piston engines". They used to run on HFO at the end, but started off on raw naphtha. Initially there were balance/vibration problems at 3000(?)hours; this was caused by carbon build up on the turbine blades, which "fell off", at a specific vibration a few hundred hours after the recommended service, (cleaning), time had passed. 
I sailed with a Scot, Willie Campbell (2/e), who had sailed with this engine, among others.


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## chadburn (Jun 2, 2008)

They were indeed "free piston powered Gas Turbine engine's" aka modified steam turbines powered by opposed piston Gasifiers. One was the "Morar" (or something like that) and the other which I mention above also known as the "Rembrandt" which operated on what was known as the "French System" or Pecasa. I only did the one trip on this vessel as at the time Gas Turbines were being promoted as you will remember as the the powerplant of the future for ships, car's, trains etc. just out of interest and a possible leg up for the future.


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## albatross1923 (Sep 18, 2006)

*morar*



chadburn said:


> They were indeed "free piston powered Gas Turbine engine's" aka modified steam turbines powered by opposed piston Gasifiers. One was the "Morar" (or something like that) and the other which I mention above also known as the "Rembrandt" which operated on what was known as the "French System" or Pecasa. I only did the one trip on this vessel as at the time Gas Turbines were being promoted as you will remember as the the powerplant of the future for ships, car's, trains etc. just out of interest and a possible leg up for the future.


Did Two trips as 2ngr on the morar back in 1961 you had to bump start the gasifiers to start them you have the right name called after a district in the highlands ship managed by DEHOLMS the official stamp on my discharge reads TV MORAR not GTV MORAR
ALBATROSS 1923


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## JET (Oct 22, 2005)

Both the Geestland and Geeststar (1960) had free-piston gasifiers and gas turbine for their main propulsion. They were both re-engined in 1967.
The free-piston concept was first introduced by R.P.Pescara (Wikipedia and others have descriptions of the design, etc under
'Free-piston engine'). I vaguely remember a free-piston unit being installed in the NZS Otaio in 1958 during construction but it never worked during the first two voyages because of problems with the supply of the turbine/generator.

Regards, John


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## johnjames06 (Jan 5, 2011)

*Diesel engine*



waldziu said:


> http://www.theengineer.co.uk/blog/queen-elizabeth-takes-its-bow/1003401.article.
> 
> Looking at the picture of the enineer working on a diesel engine, has me comfused. Have diesel engines chanches so much.
> 
> ...




Some gas turbines do run on diesel. some are dual fuel and others run on gas.


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## johnjames06 (Jan 5, 2011)

*Oil*



waldziu said:


> Don't forget OEP69, OMD112 and of course many (Pint)(Pint)(Pint)


What about main engine lub oil (turbines) OM 100. OM= oil mineral.


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## makko (Jul 20, 2006)

cryan said:


> The GT is not a diesel engine, the diesel engine is the compresion ignition engine designed by Rudolf Diesel. Incidently the Gas Turbine does not burn Diesel, it burns in the case of ships, Marine Gas Oil.


GT's are "combustion turbines". Large GT's usually burn heavy fuel oil (HFO, Bunker) or gas depending on their location. The lower calorific value of diesel oil and low efficiency of GT's in open cycle make the burning of diesel very expensive.

For example, a 100MW GT in open cycle has a thermal efficiency of approximately 37%. In combined cycle (exhaust heat recovery steam generator HRSG powering a conventional steam turbine approx +35MW) thermal efficiency is approximately 49%, similar to that of a very large slow-speed diesel.

Rgds.
Dave


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