Iowa-Class Operating Limits of the Engine - Missouri was limited

[Lord_Slayer]

Was watching this youtube from the other day from Battleship New Jersey.

They have located a document from 1987 listing the limits of the engine of the three Iowas in service (Wisconsin still under refit).

Of the three, Missouri has her own set of limits, lower then Iowa and New Jersey.

New specific reason was given for the limits, other then what is said in the video as a possibility of the age of the plant (Iowa did spend a large amount of money on her plant vs fixing the issues of the guns).

Thoughts?
 

 

[Arcus_Aesopi]

Very interesting but not surprising.  Ships are delivered with "as-built" documentation which shows the deviations from the "plan".  They're never perfect, especially when design and equipment sourcing changes occur during construction.  Sometimes ships perform better than plan, so the differences don't only go one way 🙂

I'd be surprised (maybe shocked and appalled would be a better way to put it) to see a ship that didn't have specific engineering notes and learned limits associated with her.

Thanks for sharing.  Battleship New Jersey's content is fantastic.

[Justin_Simpleton]

I think the updates of shaft speed may have something to do with the aging or fouling of the propellers/shafts and better methods of measuring the stresses on the drive train.  I heard Ryan postulate that these changes were due to turbine and boiler wear and tear but that doesn't make much sense to me because boiler capacity changes would look equal across the board and turbines just work until they don't. 

[Wolfswetpaws]

5 minutes ago, Justin_Simpleton said:

I think the updates of shaft speed may have something to do with the aging or fouling of the propellers/shafts and better methods of measuring the stresses on the drive train.  I heard Ryan postulate that these changes were due to turbine and boiler wear and tear but that doesn't make much sense to me because boiler capacity changes would look equal across the board and turbines just work until they don't. 

Ryan mentions in the video that one of the gearboxes was out-of-specification and was prone to over-heating.  Thus an operating restriction was placed on the relevant equipment.

[Arcus_Aesopi]

4 hours ago, Justin_Simpleton said:

I think the updates of shaft speed may have something to do with the aging or fouling of the propellers/shafts and better methods of measuring the stresses on the drive train.  I heard Ryan postulate that these changes were due to turbine and boiler wear and tear but that doesn't make much sense to me because boiler capacity changes would look equal across the board and turbines just work until they don't. 

Ryan has another video where he discusses the overall engineering spaces and explains which engines drive which shafts, etc.  One of the key differences is the dramatic but necessary variation in shaft lengths.  Along with that, the boilers and turbines are subject to variations both in equipment and also the personnel who operate them.  Overall it's a much sloppier process than one would think for something that does the amazing job it does.