I need to understand the SHCommander Random tonnage system

What the Random Tonnage in SHCommander doing exactly?

I went back to my patrol (April 1944) and all my Tankers were about 11k Tons.

If I check back my previous patrols, they are different, varying from 8k to 10k.

So, is this working on different times of year? Or I was lucky to bag T3s all of this weights?

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Another note,

I also noticed that the C3 draft has increased of 3 meters. Then revert to 9 meters. WTH

[Church SUBSIM]

Not sure on the random but I have burned a lot of magnetic's on C3's too.

[JScones]

Look at the SH3Cmdr file titled 'Ship displacements.cfg'. It should be self explanatory. The actual formula used is:

Tonnage = ((Round((Displacement x YearlyDispAdjust) * LowerDisp) + Random((Round((Displacement x YearlyDispAdjust) * UpperDisp) - Round((Displacement x YearlyDispAdjust) * LowerDisp)) + DispPrecision)) div DispPrecision) * DispPrecision

Generally, ship displacement increases by 2% per year.

Due to SH3 limitations, the values generated for each ship class will be the "seed" values used by SH3 for all ships of that class for that patrol - SH3 has its own randomisation which will vary the tonnage slightly. So, it's not surprising that all T3s sunk during that patrol were ~11k when they varied between 8 and 10 for prior patrols.

I'll let Observer explain further...

You get this mod with SH3 Commander. I suppose since I did it, I'll explain how it works.

The data for this is from over 3000 actual ship sinkings that happened during the course of the war. This data was broken up by year (mostly..some years are combined), and then analyzed using some statistical tools for mean and standard deviation. I generically placed ships in classes such as Large Merchant, Medium Merchant, Small Merchant and Tramp Steamer (by the way I did a mod to get rid of the C2, C3, T2 and T3 names which applied to specific classes of merchant ships and saw limited action only during the later part of the war, at least from a actual ship sunk perspective). I then randomized the tonnage values based on the mean and standard deviation. If the standard deviation was large for a given class of ships it could result in tonnages being very close to each other (i.e. C3 and C2 which I referred to as Large and Medium merchants). This isn't unrealistic because many Uboat Captain's had difficulty estimating ship tonnages unless they could find the ship in the Lloyd's registry.

Just as an aside, the same database used for tonnages was also used as data for the improved convoy mod.

Hope that's the answer you're looking for. This varies in SH3 Commander by month, so some months you may get a 3500 gross ton C2 (medium merchant) and another month you may get a 5500 gross ton medium merchant. It adds to the excitement and means you never can count on a given class of ships getting you an exact 100% predictable tonnage. Every time. Now there are some surprises, and some disappointments especially when you spend 3 torpedoes taking down a merchant of only 3500 tons.

As another aside, the renown values for ships have not been altered. You should find, on average, the results from a patrol more closely match historical sinkings from Uboats during the war on a tonnage basis.

ok, so is it normal that the Tonnage does not update in the Rec Book then?

Thanks

[JScones]

Yep. And it shouldn't. The Rec Manual lists the "indicative" (and if I'm correct, "empty") tonnage. The sunk tonnage will include cargo and the like.

Originally Posted by JScones

Yep. And it shouldn't. The Rec Manual lists the "indicative" (and if I'm correct, "empty") tonnage. The sunk tonnage will include cargo and the like.

Alright, thanks a bunch

[lafeeverted]

Originally Posted by JScones

Yep. And it shouldn't. The Rec Manual lists the "indicative" (and if I'm correct, "empty") tonnage. The sunk tonnage will include cargo and the like.

if I am reading this correctly, this is not correct. Tonnage credit was for the ship only. Cargo was not part of the calculations for ship tonnage credit. An empty Coastal Merchant is equal to a fully laden Coastal Merchant.


Ex. The Norwegian tanker Italia, sunk 14/06/40 by U38, has a GRT of 9,973 tnns. it carried a cargo of 13,000 tnns of petrol. U38 would receive credit for sinking a 10,000 tonner, not 23,000 tonnes for cargo included.

[lafeeverted]

This is not to say that the Random Tonnage feature is incorrect. There certainly was variation within the individual category of ships. Here is a good site


http://www.usmm.org/

for ships

http://www.usmm.org/ships.html

scroll towards the bottom of that link for shipping types and see the variation in tonnage. Nicely reflected by SH3Cmndr

[JScones]

Originally Posted by lafeeverted

if I am reading this correctly, this is not correct. Tonnage credit was for the ship only. Cargo was not part of the calculations for ship tonnage credit. An empty Coastal Merchant is equal to a fully laden Coastal Merchant.

Yeah. I thought this after I wrote it, but knew I'd be corrected if I was wrong.

Ultimately, the Rec Manual is meant to be indicative only. It's not meant to reflect *exactly* the tonnage for each class during each patrol. Beery would have explained it better than me though if he were around.

As an aside, note that some ship tonnage, like the Liberty and Victory Cargos, is not varied in SH3Cmdr - they keep the same displacement throughout the whole war.

[lafeeverted]

I was wondering about the Liberty/Victory ships myself. I originally thought the mass produced ships should be all the same GRT. However, there were within the Liberty Class, 3 different types. It is possible that they might vary in GRT as well??

[iambecomelife]

Originally Posted by lafeeverted

if I am reading this correctly, this is not correct. Tonnage credit was for the ship only. Cargo was not part of the calculations for ship tonnage credit. An empty Coastal Merchant is equal to a fully laden Coastal Merchant.


Ex. The Norwegian tanker Italia, sunk 14/06/40 by U38, has a GRT of 9,973 tnns. it carried a cargo of 13,000 tnns of petrol. U38 would receive credit for sinking a 10,000 tonner, not 23,000 tonnes for cargo included.

Yes. Most measurements of U-Boat victims that I've seen use GRT. GRT is more like a unit of space calculation than an actual "weight" measurement. Therefore it remains constant regardless of whether a vessel is in ballast or loaded.

[lafeeverted]

If there were a way to add more uncertainty to the tonnage sunk aspect of the game....... :hmm: U-Boot Commanders faced that question unless they could positively identify a ship through the registry. Miss identified ships/tonnage over and under estimates were part of the game for them. In SH3 you are limited by the type of ships available, every ship that is in game is identifiable through the Rec manual.So within a percentage, you know what you have sunk. You also get an updating tonnage score when you save each mission.Using the NYGSDM, ship sinking has been dramatically improved. If I remember correctly, SH3 will not give you credit for a ship sunk unless you are within a certain distance at the time of sinking? If you get tired of waiting for the ship to sink and leave the area, you can still get credit for the sinking within a distance and receive that confirmation without witnessing the actual sinking.Perhaps with SH3Cmndr a few things could be changed to add more uncertainty. The running total of actual tonnage sunk (shown in the patrol logs and mission exit screens) could be blanked out or perhaps only show the Rec manual estimated tonnage(this would be approx what the commanders claimed tonnage would be) . Actual tonnage sunk would not be available until after a patrol was completed. if you are playing on higher realism levels and can't resist the temptation to enjoy all the graphics of SH3, using the free cam will let you know if you hit the ship you were attacking in the convoy everytime. It is for those moments when you launch a salvo but have to dive to avoid detection or destruction that the uncertainty of your results can enhance the game. Did all the torps explode on impact? Did they explode on end of run settings or detonate prematurely ? Did I actually hit my target or miss and get something else? These questions are often answered by the ever present tonnage score.

[iambecomelife]

Originally Posted by lafeeverted

I was wondering about the Liberty/Victory ships myself. I originally thought the mass produced ships should be all the same GRT. However, there were within the Liberty Class, 3 different types. It is possible that they might vary in GRT as well??

Interesting. What were these types? I thought all Liberties were basically the same except for some tanker conversions.

I bet the reason why SH3 doesn't allow for AOD-style tonnage variation is because it needs to minimize the variations between the mass-produced ships. It must use the same variability for these vessels and the generic classes (coastal merchant, etc).

[lafeeverted]

I was looking at this information all morning and now i cannot find it There were three Victory's listed. How much of a difference among them, if any, I cannot determine.

Victory
Victory Collier (?)
Victory tanker conversion

I will keep looking

[JScones]

http://en.wikipedia.org/wiki/Liberty_ship states: "Sixteen American shipyards built 2,751 Liberties between 1941 and 1945, easily the largest number of ships produced to a single design."

Not sure whether to read that as meaning only one variation was made?