Merchants vs Warships
 

DesirableRoasted made a comment in another thread (http://www.subsim.com/radioroom/show...4&postcount=19) that I think deserves it's own thread, as it would derail the original topic, and by god, we don't go OT here at Subsim.
Yes, I agree our primary mission is the sinking of merchant shipping in hopes of blockading the British Isles.

But is it really a waste to attack a warship or two when that will allow us to sink more merchant shipping? If we find a weakly escorted convoy, or during a harbor raid, we sink the lone ASW craft, allowing us free reign of the docked merchants.

Ie, from a patrol I did early in the war:If I had left the lone DD alone, then at best I would have gotten a shot at the Battleship, or maybe the two whale ships. But by taking out the escorts first, I could decimate the convoy.

Opinions? And I'm talking both historically, and game wise, which we know are two separate realities.

Historically speaking I think a sub doing this would have been sunk as soon as they could find someone in the harbor who hadn't died of laughter. In game it's of course a different matter.

Sinking a destroyer does indeed often seem like a waste of resources in most cases, though it is satisfactory to say the least. And I agree that if a convoy has very weak escort and is in the middle of nowehere, then it might be a good idea too. I remember doing it occasionally on Mediterranean when I kept bumping into convoys consisting of only two or three merchants and just one destroyer. Then again, for some reason I often liked sinking the biggest merchant from under their noses anyway.

Total warfare
 

1939-vintage British BBs cost about 12,000,000 pounds sterling to manufacture, or $48,000,000 1939 USD, ~ $750 million 2010 USD.

Liberty ships cost about $1.6 million 1941 USD/400,000 pds sterling to manufacture, plus value of cargo, much more than cost of the ship.

But of course, there were only 19 British BBs worldwide and thousands of Liberty ships, so you have to factor in strategic target value. Just talking BBs here, not CVs or CAs.

Here's an excerpt from a good read:

http://www.navy.mil/navydata/cno/n87...campaigns.html

Note that the $$ value of allied military shipping destroyed by Uboats was about 66% of merchant shipping/cargo NOT INCLUDING cost of major capital ships sunk.

APPENDIX 1: CALCULATION OF BATTLE OF THE ATLANTIC COSTS
Allies:

A. Merchant Ships:
1. Cost of merchant ships lost to sub attack: 14,687,231 tons lost at $420 a ton.
2. It is assumed that 50% of destroyed ships had cargoes and I have estimated the value of each cargo as equivalent to the price of the ship.
3. American Maritime Commission constructed 5,777 ships of 39,920,000 tons during the war that cost $14.2 billion. It is estimated that only 2/3 were used in the Atlantic (this accords well with 61% reported in Leighton's Global Logistics 1940-43 (p.662) which was prior to the increase in lift necessary to handle Overlord).
4. The English and Canadians produced 11.9 million tons during the war. It is assumed their cost of production was as low as in the U.S.
5. The English started the war with 17,430,000 tons. The Americans started with 8.5 million tons (again only assumed 2/3 used in Atlantic). Additionally the Allies seized 3 million tons of shipping from nations occupied by the Axis.
6. It is assumed that 33% of the total merchant fleet was lost due to inefficiency of convoying. That is 11.36 million tons at $420/ton.
7. Repair costs from U-boat attacks were not included.
8. Total: $14.65 billion.

B. Warships:
1. The Americans had 140 destroyers stationed in the Atlantic. Each cost approximately $10 million. Additionally, they had 56 frigates assigned to the Coast Guard. I've estimated their cost as similar to a new frigate ($2.3 million).
2. During the war, the U.S. produced 520 destroyer escorts (DDE) and 96 frigates (FF) for convoy protection. A DDE cost $5.5 million and a FF cost $2.3 million apiece.
3. The Allies built 61 escort carriers that participated in the campaign at a cost of $12 million a piece.
4. The English and Canadians built or seized 169 DDEs. I've estimated their costs as equivalent to a Hunt class DDE ($6.4 million). They also built 156 frigates, 63 sloops (estimated to cost $4 million), 306 Corvettes, 27 other ASW vessels, and 15 armed merchant cruisers (all estimated at $3 million).
5. The English employed about 302 fleet destroyers during the war.
I've estimated that only 50% of their missions were related to ASW and that they cost the equivalent of an U.S. destroyer (a probable underestimation).
6. The cost of coastal defense craft and minesweepers used for ASW missions was not estimated.
7. The cost of major warships sank by submarines was not used in the estimate. [N.B. - see commens above re: BB cost of manufacture]
8. Total: $10.15 billion.

Game Tactics

The example Gargamel presents is an excellent example of "the theoretical exception proves the rule." If I encountered one ASW escort guarding a BB and a flock of large merchants, whalers, etc., in 1939, then of course the escort is the first target -- I don't care the convoy is alerted, as even their zigzagging presents no great challenge.

But I would have to know in advance it was the only escort, and I am scratching my head trying to recall an instance when I would have had that perfect knowledge.

Even in broad daylight, clear visibility, you rarely can see to the far end of the convoy, unless you use the "X-ray vision lock" exploit. So how are you to know there are no escorts? And in optimal attack conditions (dusk, moderate visibility), you sure aren't going to know.

So, without that knowledge, what do you do? You take down the sheep, not the border collies. If there is only one escort on the flock, that will become apparent soon enough.

Reality

Here, it's just logic. If the merchants are being guarded so carefully by sophisticated escorts, it must mean they are valuable and worth sinking.

And here, the price of replacement, etc, is not particularly relevant. Even cargo value is not necessarily relevant. A box of machine tools, while costing far less than a destroyer, might be essential to making 20 new ones. A merchant and a cargo of wheat don't cost much, but losing 2-3 a week can be the crucial thing in public morale. far more demoralizing than the loss of a destroyer (which might not even be reported in the papers until weeks later).

Game tactics + Reality

Escorts are just a part of the day at the office, and a distraction. My job is to sink merchants. If doing that means I have to sink an escort -- perhaps once out of 25 patrols -- fine, but it is out of necessity. I consider it a wasted torpedo.


But

I like seeing the pesky maggots go KaBoom as much as anyone. But only once in 25 patrols.

Edit

BTW, if you do like taking on escorts and battleships, be up in Narvik on April 10-13, 1940. You will get your fill of both and you will learn more than you want to know about shallow-water defense tactics.

Really good points
 

Very well put, agree 92.6% :03:

It's a bit of a quibble to say cost of replacement isn't necessarily relevant. Obviously, it's as good a proxy as we have to try to get a handle on the value of what you destroy. Let's put it this way: if a kaleun sank the HMS Hood, would it really matter what he did the rest of his career? Of course not.

Personally, I wouldn't engage one of these wandering DD groups any more than I engage coastal merchants. I don't go after anything less valuable than a C2 unless I'm on the last leg of the trip home.

I'm of two minds on targeting the convoy escort thing for the reason you gave: you usually don't know what else is in there unless you've shadowed the thing for a long time. But at the same time, I'm usually greedy and plan on reloading and taking another bite at the apple in a few hours, so taking out the border collie is very tempting.

Did anyone ever take a warship down by accident, as in it took the torpedo meant for a merchant?

Who sank the Courageous?

Who's the leading Kaleun in tonnage?

which of those two do most people (subsimmer's) know off the top of their heads.

Well, now you are talking apples and oranges. Hood isn't an escort, it is a national icon, and a capital ship, albeit an aging one. And, for game purposes, you can see it as a 36K ton merchant, because it reacts like a merchant. So of course you sink it.

When I say "escort" I mean naval ships that carry out anti-submarine warfare against you in the game. DDs, ASW trawlers, corvettes, etc. As I said, going after them is like going after the border collies rather than the sheep.

Most of the small warships (DD, DDE, FF, trawlers...) listed in my sig were self defense. Others were guarding convoys or ports, allowing me to reload torpedoes or even engage on the surface without fear. I would rather use my fish on a merchant or large warship (CV, CVE, CA, CL).

That said, destroyers have such low health that a torpedo makes nice fireworks.

There's a line from a documentary I watched recently that stuck in my head. It went along the lines of -
"It was a tonnage war - the aim of the KM and specifically the U-Boat fleet was to sink tonnage at a faster rate than Britain could replace it, either through building or buying."
ASW ships don't normally tip the scales as high as a merchant, therefore to stick with the "big picture" merchant shipping should always be the primary focus - in my opinion.

But in the same respect, as I thing the OP had asked it, in a quite large convoy with around 4 DDE's (I quite usually spot them with this many) you spend one torp on each escort, and its open season on the convoy. Ive done this a few times, and the funny thing is (This is early war mind you), after one sinks, they come after you in a one by one basis which is handy. Ive done it before and once only and I do say it paid off.

But as desirable said, realistic?? Very hardly

Put yourself in the shoes of that Kaluen, is firing at that 1,000 ton escort from open water worth the chance of your life??

or is sneaking in and sinking the 10,000 ton large merchant then using the confused convoy to as a screen to slip away untouched worth it more??

^This is of course if you play DiD

Another thing to consider, The kreigsmarine surface fleet was stuck in port most of the time, due mainly to them being vastly outnumbered.

If the Uboatwaffe had made a concerted effort against the warships of the RN, that may have allowed the surface raiders of the OKM to sail more often, the cruisers and battleships could inflict vast more damage against a convoy than a couple u-boats.

Of course, with Donitz only having 20 or so U-boats at the start of the war, this wasn't practical.

So its kind of a grey area? Because one one hand realistically, the U boats should have gone after war ships, less warships means more easy targets for all surface ships. on the other tonnage is what they were supposed to focus on not to mention, intsead of sinking a convoy of easy 'targets' they could have just as easily threatened them to change course and brought them to Germany to use the supplies for them instead. As well as the ships. a cheaper more effective way! lol

I'm not dogmatic about this. I won't attack lone destroyers, or spend several eels on escorts if I fear there will be new cover before I have made a dent into a convoy.

However, I'll spend the torpedos if blowing up an escort or two means I can sink merchants with my deck gun or when it seems a lot safer than to disengage and sneak away. DiD, and I try to get boat and men back in one piece - I'm not having trash cans dropped on my head if I can avoid it.

Capital ships will be targeted over anything else.

I doubt the strategy of going after warships in order to strip merchants of escorts would have worked even with much more U-Boats available. After all, it doesn't cost that much to churn out something like Flower class or ASW Trawlers - just take cheap civilian ship design, mount a gun, DC rack and ASDIC dome and you've got a vessel capable of taking on a U-Boat while being much less expensive. I suspect Allies could produce cheap ASW ships faster than Germans could destroy them, even if they go after warships alone.

Also, for taking out the lonely escort to finish off entire convoy with deck dun - AI is not flexible enough to scramble every plane from nearby airfields, every warship from nearby port and half the escort of other convoys to rescue ships in danger, to disperse a convoy if necessary or to make good attempt at ramming the "clever" U-Boat to death. Or, to start giving out machine guns to every merchant crew before leaving the port. That's why we can try it and real U-Boats couldn't.