The Ship Model Forum

SG has nothing really to do with engine performance, it's relevant for tank capacity and important for fuel treatment but it won't have an impact on boiler performance.

Thank you Phil, I'll be sure to capture those figures on camera in the future.

Something on the actual question asked (!)

I knew I'd seen something and I looked at my photos of the "Particulars of Vessels and Aircraft" and in the back they have bits on endurance.

From at least the April 1939 through to April 1941 there is a note that procedes the endurance tables (after the April 1941 issue the comment is dropped but the endurance tables are expanded).

This states that the figures are based on 95% of the total volume of the ships bunkers with oil of specific gravity of 0.933 (240 gallons per ton). It notes that Admiralty stocks of bunker fuel ranges from 0.960 (Trinidad) to 0.895 (Persian) at 60-degrees F.

It makes no comment about any difference in calorific, or other, value and the endurance tables don't make any mention of any differences, either.

So the only really relevent comment is that Trinidad oil was being regularly stocked pre-war.

[quote="Werner"]The [i]Spruance[/i] had a heck of a time when she was new. Changing fuel filters twice a day was not uncommon. Then she deployed to the Mideast. The filters lasted weeks!

Turned out the domestic US suppliers were pouring recycled crankcase oil into the fuel as a standard operating procedure.[/quote]

Yep, blending with waste oil is another classic, residual fuels are real junk. Then there is the possibility of bugs in the fuel, padding it out with sea water etc., it's a minefield.

For those interested, the subject is well covered in most standard marine engineering text books if you have access to a technical library or live near a marine college.

The journals are very much professional journals for engineering officers. They are written by and for practical engineers rather than academics.

They change over time. The post-war ones are really about running a ship, tips on how difficult situations were overcome and reviews of new types of engineering plant.

The more recent ones (the latest I have is nearly 15 years old) are more reviews of the introduction and running of equipment.

One post-war one I have does have info on the comparison of various steam plant during the war - but does not cover oil types.

Thank you Phil,

Just had a peak in my uni library, as we have a good engineering department there, but unfortunately its mostly automotive and aerospace, though I did notice these though:
[list]
Proceedings [of the Institution of Mechanical Engineers] Part M : journal of engineering for the maritime environment.
Royal Institution of Naval Architects Transactions [of the Royal Institution of Naval Architects]. Part B: international journal of small craft technology.
Naval architect
Naval research logistics.
Naval research logistics quarterly
Institution of Engineering and Technology: Radar, sonar & navigation.
Institution of Electrical Engineers: Proceedings. Part F : radar and signal processing.
Institution of Electrical Engineers: Proceedings. Part F : communications, radar and signal processing.[/list]

Most look fairly newish and only go far back as the 1980s, but you never know I might find something useful in them.

I agree though it will be the older journals you mention I need to go through.
I'll have to ask David K. Brown where best to go to look through 'Journal of Naval Engineering', and its predecessor 'Papers on Engineering Matters' as I'm not precisely aware of where the a good naval engineering library is in the RN nowadays.

I've only ever had the chance to look through an old copy of transactions, which was more about warship design.
From the copies you have then, whats the format please are they easy to read?
Do they have have plans and photos? or are they dry science journals?

Finally doing my own detective work it would appear that the engineering school in the RN presently is: 'HMS Sultan is the home of Royal Naval School of Marine Engineering (RNSME) and the Royal Naval Air Engineering and Survival School (RNAESS) whose primary function is to supply the Fleet with engineering Officers and Ratings of the highest quality.'
This is in Gosport and isn't one of the RN bases I'm familar with in my sea cadet days. :big_grin:

[quote="Laurence Batchelor"]No I haven't, another is [i]Transactions[/i] I believe
Is there an index online of their past articles like most academic journals?
Which places has a set of copies of these journals to look through?
Finally rucially do they write in techno-babble or in plain english helping
the general reader?[/quote]

These are the RN's own journals (usually classified as restricted or confidential).

The Historical section does NOT have them, but IF there is a library at the Engineering Station they might have them.

They turn up on the second-hand market every so often (I have a few).

No I haven't, another is [i]Transactions[/i] I believe
Is there an index online of their past articles like most academic journals?
Which places has a set of copies of these journals to look through?
Finally rucially do they write in techno-babble or in plain english helping the general reader?

Laurence,

Have you seen the series of RN journals "Journal of Naval Engineering", and its predessor "Papers on Engineering Matters". They cover some of these issues.

The [i]Spruance[/i] had a heck of a time when she was new. Changing fuel filters twice a day was not uncommon. Then she deployed to the Mideast. The filters lasted weeks!

Turned out the domestic US suppliers were pouring recycled crankcase oil into the fuel as a standard operating procedure.

The science of oil fuel is an subject in it's own right and is a major headache in industries reliant on it. With distillates there are some pretty well defined international standards on ignition timing, combustion quality, residues, contaminant content etc. but when you go into residual fuels the quality is a lot less well defined even with various ISO grades and accepted contract grades. The sort of 600cst muck now burned in commercial vessels is the absolute dregs, even the better 380cst can destroy an engine if there is a slight discrepancy in composition up that suppliers are less than honest about. There are various tests which are performed such as;
kinematic viscosity
water content
catalytic fines
closed flash point (critical for legal reasons on fuel storage)
calculated carbon aromaticity index
conradson carbon residue
compatibility
but customers still get caught out and end up with massive repair bills. In particular, unless you're in a position to wait for a full fuel lab analysis report from a specialist like FOBAS it's not possible for routine tests to establish contaminants like Vanadium which can cause all sorts of problems, it's hard to establish Sulphur content, various crystalline impurities and waste products (believe it or not some refineries, especially US ones, dispose of stuff like polyproylene rope by blending it into residual fual, which causes massive machinery problems).
Basically fuel quality is critical to engine performance and longetivity, reducing down time etc, including on steam plant. A lot of people think boilers will burn anything but they're very prone to slagging, blowing tubes due to combustion deposits building up on tubes and poor performance due to low CV fuels and inadequate transfers. So yes, most plant is based around a particular fuel quality and if you deviate from it you run into all sorts of problems.

I'll try and stop being the perfectionist and take a delve into amateur dramatics.

[quote="ar"]Stop thinking and start writing, warts and all. It's AN ARTICLE, later on you can delve, but NOT NOW. THis is just a walk on part, a one liner.[/quote]
You sound like my old graduate adviser!

Stop thinking and start writing, warts and all. It's AN ARTICLE, later on you can delve, but NOT NOW. THis is just a walk on part, a one liner.

I wish to get a flavour of the operational also.

One thing also which got me thinking and I really could not formulise an answer in my mind is this:

There were three routes from Dunkirk to Dover X, Y & Z.
Route Z passed West along the French coast and very near to Gravelines & Calais.
I've read numerous reports of Dunkirk vessels being shelled from shore batteries (perhaps captured coastal French guns or from German field artillery stationed there).
Now my problem with this is why on earth did the Admiralty not respound to this with a shore bombardment, either in the day or at night?

As a result of not sorting out this danger the convoy routes back to Dover went up from 80 miles (Route Z) to 172miles (Route Y), which was later cut to 108miles (Route X).
Routes X & Y being a more out-of-the-way Northerly route.
All significant delays in fuel, ships and time.
All it would have took would have been one 6-inch gunned cruiser or if they were concreted in 1 battleship either of which were not suffering from a pressing shortage in May-June 1940.
There were no enemy mine fields or nets in the Channel by this time to get in the way.
Allied maps were marked with all the French and British ones.
The Admiralty also had clear signals coming in telling them where this fire was located and what damage it was causing to Dynamo as a whole.

I can easily understand the inability to deal with the air threat, E-boats, mines, lack of small craft etc, but the above problem seems easy to solve? Especially at night.

[quote="Laurence Batchelor"]I
Finally when we began to use American crude in quantity was this up to Persian standards or better?
If it was, why did we even bother to buy oil from Trindad and Venezuela in the first place, was it just very much cheaper from there?[/quote]
I'm sure Chuck has access to the details, but I believe you'll find an oil called "West Texas Light Sweet" is the benchmark against which all crude is judged for purity.

I am glad to hear that you have actually put some words down on paper, or at least I assume so. I estimate that you have about five hundred words on paper so far. No doubt your frustion has gone that you once had now that you have started.
I and others look forward to seeing the first article in print very soon.
Note what I said earlier, just a selection from the damage reports is all that is required to give the reader a feel for what happened in terms of the technical.



[quote="Laurence Batchelor"]It doesn't directly, but its a general wartime point I spotted which seems unexplored by previous authors, Raven & Roberts and Friedman included.
and I posted this before the Dunkirk reployment.[/quote]

What I have seen of bunker oil is that the darker and heavier it is, the larger the fraction of carbon is bound to the impurities, fouling your burners. Secondly, if the oil is unrefined or partially refined, there will be a quantity of paraffin and gases which will disassociate from the oil as it is heated prior to burning. These gases and light fractions are dangerous if they are not burned separately or vented in some way.

When you think of bunker oil, remember this is a liquid that you have to heat above room temperature with steam before it will even flow properly to the burner. It looks like nearly set black epoxy.

The impurities in the exhaust flow accelerate the erosion of boiler stays and other metal parts in the exhaust stream. This was already a problem with WW.II era British boilers before adding sulphides and nitrides into the exhaust.

BP Whiting Indiana is converting to process Canadian tar shales. There is a huge local row because BP wants to dump water contaminated with by-products into Lake Michigan, which has been promised by international treaty to be kept as clean as possible. The contaminants they expect to dump include ammonia and mercury. Although Indiana has granted a permit, I doubt the other authorities, including the US EPA and the Great Lakes Consortium will really let this go forward.

It doesn't directly, but its a general wartime point I spotted which seems unexplored by previous authors, Raven & Roberts and Friedman included.
and I posted this before the Dunkirk reployment.

The RN has an engineering library somewhere, or they did have when I was out and about.
I don't see how this applies to Dunkirk though?