Ocean Going Ships: How and how often do they change oil?

11GTCS said:

In reply to ProDarwin :

Given that the bore and stroke on these engines is measured in meters there's a pretty significant side thrust component that needs to be considered.  They're somewhat similar in that way to old school reciprocating steam engines which is whole other rabbit hole we could jump down.   Full ahead RPM on one of these engines would be about 130 RPM from what I'm remembering if that helps illustrate.

If building a typical way, the rod length looks like it could be a mile long though, making side thrust much lower (respectively) than a traditional engine though, right?  What they are doing here seems odd.  I would think you'd want the wrist pin (crosshead bearing) as high as possible in the piston without compromising strength.  

I'm sure the engineers had good reason for it, but once the rod is fixed to the piston as a single unit with no moving parts... might as well just be a big piston, right?  Is there a difference?  I'm really curious what exactly the crosshead guides are.

AnthonyGS (Forum Supporter) said:

They do not do oil changes unless something goes terribly wrong.  They do constant lube oil purification though.  They are continuously cleaning their oil.  

 

This. We used to do testing for a major oil company that handled a lot of the container ships in the caribbean etc. Most of their fuel oil contains a E36 M3load of Vanadium which you won't see anywhere else and they had to be run on seperate instruments to no contaminate the next 200 samples. 

Their sumps are usually in the thousands of gallons for lubricating oil with multiple filtration systems in place. It's very dirty, very old and they have so much Phos and Zinc in them that their Base Number (someone mentioned it as TBN earlier) is in the 40's where a typical large diesel truck engine is 10-12 with the older oil, and 8-10 with the newer. They spend more time determining if their dispercents are still doing their job or if they need to add a few hundred gallons of fresh oil to sweeten it up. 

IT's really fascinating looking at these samples compared to the normal stuff. You wouldn't think something carrying this much crap around in it would lubricate, but their bearing tolerances are not the same as what we typucally consider just due to their enormity of scale. 

11GTCS said:

Turbo_Rev said:

I know we only changed the oil on our steam turbines maybe once every 5 years? TEP 2190. I don't remember the exact interval but it was very infrequent. 

We were also constantly cooling and purifying oil. We used Sharpels or DeLaval purifiers, don't remember which. Both are centrifugal. Cooling was via seawater heat exchangers. 

Geared steam turbines wouldn't have anywhere near the contamination that a propulsion diesel would and what you're stating is exactly what I remember from the steam ships I was on. 

Side note, my son is an Aggie (MS in '21) and y'all are currently borrowing the former MMA training ship until the new ships are ready.  Gig em, horns down, etc.!   I thought MMA was a cult until I took a walk around the campus in College Station and took in a football game at Kyle Field, y'all have it going on. 

4 years on a nuclear powered carrier (CVN-71) & worked in the reactor side (engine room is split into two areas, reactor components and regular steam components, blanking on the exact terms).

We changed oils and grease in various components but the 4 main engines were driven by steam turbines.  I worked on the reactor side, closest we had were 4 steam turbine driven electrical generators that powered all the reactor components, I forget if the main generators were on my side or the regular side.  Also had two separate engine rooms and reactors. 

TL;DR - I had some experience but not the right kind.  Nvrmnd.

11GTCS said:

Turbo_Rev said:

I know we only changed the oil on our steam turbines maybe once every 5 years? TEP 2190. I don't remember the exact interval but it was very infrequent. 

We were also constantly cooling and purifying oil. We used Sharpels or DeLaval purifiers, don't remember which. Both are centrifugal. Cooling was via seawater heat exchangers. 

Geared steam turbines wouldn't have anywhere near the contamination that a propulsion diesel would and what you're stating is exactly what I remember from the steam ships I was on. 

Side note, my son is an Aggie (MS in '21) and y'all are currently borrowing the former MMA training ship until the new ships are ready.  Gig em, horns down, etc.!   I thought MMA was a cult until I took a walk around the campus in College Station and took in a football game at Kyle Field, y'all have it going on. 

And turbines like this are tested on a monthly basis for multiple reasons. Their test suite is entirely different than what a normal engine oil testing would be. There's specialized testing and personnel that do that. 

In reply to Jerry :

Reactor Auxiliary Room (RAR) is the term you're looking for. Ship's service generators (SSTGs) were on the steam plant side. RAR had CTGs. 

I was on the TR from '10-'14. 2 RAR. When were you there?

In reply to Turbo_Rev :

Summer 1987-August 1991. Got to experience Shock Trials late '87 and Desert Storm January to July '91.  Up in #1 plant.

I was qualified all the mechanical watches including CTG Watch and Chief Reactor Watch. Feed Control was probably my favorite, more switches and dials vs manual labor.

Sorry to hijack the thread...

I was under the impression the backup diesel generators were started with compressed air. They had a compressed charge from the steam side and if the reactor went down, throw the lever and the big diesels came to life. 

Sidetracking to the Locomotive engines, those were 2-cycle engines until the Tier 4 EPA changes back 9-10 years ago?  I worked with the engineers at Progress Rail and it never occurred to ask about the oil amount and oil changes.

I was too worried about the oil lines we made that might leak.  
 

I can't say for ships but a good friend works on tugs that used to run EMD and Fairbanks. These were older tugs built in the 50s and 60s. They never changed the oil in them. The tugs carried around 500 gallons of oil as well as makeup oil to replace what was lost. Every x number of hours they would bring in a truck that cleans or as they said polishes the oil, tests it for additives, and adds whatever additives have been depleted. 

Datsun240ZGuy said:

Sidetracking to the Locomotive engines, those were 2-cycle engines until the Tier 4 EPA changes back 9-10 years ago?  I worked with the engineers at Progress Rail and it never occurred to ask about the oil amount and oil changes.

I was too worried about the oil lines we made that might leak.  
 

Fun fact, they put silver in the wrist pin bushing on these so that when they tested the oil they could determine if it needed a tear down or not. I wish I had a dollar for every one of those I retested to verify it had 3-4 ppm of silver in there because that's a costly mistake. 

ProDarwin said:

11GTCS said:

In reply to ProDarwin :

Given that the bore and stroke on these engines is measured in meters there's a pretty significant side thrust component that needs to be considered.  They're somewhat similar in that way to old school reciprocating steam engines which is whole other rabbit hole we could jump down.   Full ahead RPM on one of these engines would be about 130 RPM from what I'm remembering if that helps illustrate.

If building a typical way, the rod length looks like it could be a mile long though, making side thrust much lower (respectively) than a traditional engine though, right?  What they are doing here seems odd.  I would think you'd want the wrist pin (crosshead bearing) as high as possible in the piston without compromising strength.  

I'm sure the engineers had good reason for it, but once the rod is fixed to the piston as a single unit with no moving parts... might as well just be a big piston, right?  Is there a difference?  I'm really curious what exactly the crosshead guides are.

Here's a pretty good cutaway image of a typical slow speed direct drive marine diesel engine.  The crosshead is needed due to the length of the piston stroke and the angle of the connecting rod relative to the piston rod, the side force needs to be managed.  Again these are very slow running engines at about 130 RPM or so.

Jerry said:

In reply to Turbo_Rev :

Summer 1987-August 1991. Got to experience Shock Trials late '87 and Desert Storm January to July '91.  Up in #1 plant.

I was qualified all the mechanical watches including CTG Watch and Chief Reactor Watch. Feed Control was probably my favorite, more switches and dials vs manual labor.

Sorry to hijack the thread...

So, am I the only one looking at that pic wondering what's going on? That looks like an impressively large big badda boom

In reply to XLR99 (Forum Supporter) :

Shock testing.  It's indeed a big badda boom.

So we intentionally drive our capital ships past large bombs and detonate them?

Once again, I feel like I missed my calling

Is the connecting rod being split into two parts so they can keep most of the lubricating oil away from the combustion process? It looks like it allows a seal between the crankcase and the top end.

bobzilla said:

I was under the impression the backup diesel generators were started with compressed air. They had a compressed charge from the steam side and if the reactor went down, throw the lever and the big diesels came to life. 

I may know a tiny bit about nuclear power myself.  Yes backup diesels are typically started by air.  And subs don't change oil but just purify it continually.  I only know of one sub that did a full change and that was due to a big mistake that overcooked it and carbon fouled entire systems.  

XLR99 (Forum Supporter) said:

Jerry said:

In reply to Turbo_Rev :

Summer 1987-August 1991. Got to experience Shock Trials late '87 and Desert Storm January to July '91.  Up in #1 plant.

I was qualified all the mechanical watches including CTG Watch and Chief Reactor Watch. Feed Control was probably my favorite, more switches and dials vs manual labor.

Sorry to hijack the thread...

So, am I the only one looking at that pic wondering what's going on? That looks like an impressively large big badda boom

As mentioned, Shock Trials.  I had just missed it's maiden voyage when I got there in mid 1987.  The next cruise was around September or so, where they test to see what happens when large piles of TNT are blown up next to the ship.  They rig sensors around various places, set General Quarters, and they count down to the detonation.  We were told to stand leaning against a wall on the balls of our feet.

They did this 3-4 times over a couple weeks, each time closer to the ship.  That might have been the last one, closest.  I was still in Reactor Training class at the time, just before being sent to the engine room.  My GQ station was a classroom, I remember whole walls of pop rivets failing and having to re-build walls.  I don't remember hearing anything terrible happening down in the engine rooms.  Rumors were that trials of a previous ship made it Dead In The Water (both reactors tripped and shutdown) on test #3.