ENGINE DESIGNATIONS AND MEANING

ENGINE DESIGNATIONS AND MEANING

We always hear this statement or tell others that:
"oh i have workd on 6S50MCC engine on my last ship"  or "my last ship was propelled by SULZER RTA68-7-flex engine"

Now do we really understand what the above statement means or what are we talking about?

We have worked on different types of MAN and Sulzer engines in the past and will continue to do so.
We have come across so many engine designations and types in our past, but how many of us know exactly what these designations mean?  This post mainly deals with Engine Designations and what story they tell us about that particular Engine.

P.S. - this post is dealing with only MAN and Sulzer make engines.

MAN B&W Engines

Below picture illustrates MAN B&W Engine Designations.
P.S.  We are not dealing with the old designations of EE, FF, GF, GFCA, GB as these types of engines are now getting obsolete.
Picture explains it all so no further description is required.

Now that we have Learnt about MAN B&W Engines, lets now take a look at Sulzer Engines.

SULZER ENGINES

Unlike MAN B&W engines, Sulzer Designations do not have any technical meaning but simply kept as an easily recognised identifier for the Sulzer low-speed engines.
The letter "R" in the RD, RND, RND..M, RLA, RLB, RTA and RT-flex engine types, goes back to the Sulzer RSD two-stroke, low-speed engine types introduced in the 1950's. The letter "R" stood for "REVIDIERTER" which is a german word for "REVISED".  During this period SD engines were "REVISED", and so were denoted with letter "R" and called RSD.  Then in 1956 RSAD engines were introduced which were the turbocharged versions.

However as of today letter R has lost any connotation with "REVISED" and now is simply kept as an easily recognised identifier for Sulzer low-speed engines.
When electronically-controlled common rail systems were introduced in 1998, the designation RTA was adopted to RT-flex to emphasise the key feature of "FLEXIBILITY" given to the new type of technology.
Also RTA engines represent uni-flow scavenged engines (with exhaust valve). So now if somebody talks about SULZER RTA68-7 then it simply means -
 SULZER RTA -  uni-flow scavenged engine (with exhaust valve)
68 - Diameter of Piston (in cm)
7 - Number of Cylinders

So now if some body asks you or tells you "oh i have worked on 6s50mcc engine on my last ship"  or "my last ship was propelled by SULZER RTA68-7-flex engine"  you now know the answer.