Merchant ship damage durability

[RAM]

ORIGINAL: pasternakski

H.M.S. Hood was a design from the British "exploding battlecruiser" period of 1914-1917. Several other examples were detonated at Jutland. It should have been no surprise that this ship went up like a celluloid collar against Bismarck.

this is running a bit off topic, but to make things short, no, HMS Hood wasn't a design from the flawed Fisher idea of "speed is the best armor". The original drawings for the ship were badly protected, but after Jutland had taken place the Admiral class Battlecruisers were thoroughly redesigned, and all work on HMS Hood (wich was in a very early stage of building) was stopped for months so she could be modified acording to the new armor schemes of the new design.

All in all the HMS Hood of 1919 was an ,if not excellent, at least very well armored ship, sporting armor comparable to that of some of the RN Battleships (something unthinkable in the pre-jutland times).


The fact that the HMS Hood blew up at the Denmark Straits had a lot to do with her having a badly outdated armor scheme (in 1916-1919 vertical protection wasn't as important as in 1941) which needed an urgent update (was scheduled for 1942), something shared with many battleships of her age or even newer, as, for instance, the japanese Nagatos, ships with a quite weird armor scheme that left some angles completely free for enemy shells to burst into her vitals.

It may have had a lot to do with the actual age of her armor, too. There are some accounts that point out that HMS Hood's armor had, after so many years of service without a really thorough and proper refit during all of them, become brittle and much less resistant, wich may have had also to do with the actual hit which blew her up.


To argue that Hood sank because it was a battlecruiser instead of a battleship is quite unfortunate; firstly because in fact she wasn't a battlecruiser according to the RN standars of 1914 because she didn't trade off armor for speed, neither she was a battlecruiser according to German Standards as she had excellent top speed coupled with a powerful main battery (the germans sacrificed firepower instead of armor, for speed). That was the main reason behind her enormous size and great tonnage for her completion time, 45000tons were needed to hold the neccesary machinery to put that great amount of armor and firepower running at 30knots, while the biggest battleships and battlecruisers of her time (1918) didn't go over 35000tons.

Secondly because many other ships, being called Battleships, were as vulnerable as HMS Hood to sink in a similar way because their vitals, once well protected, weren't well armored for the standards set 20 years after their completion.



If Nikademus happens to read this he may ellaborate a bit more, he's a true BB and BC nut .

[Panzer76]

My question was primarily about merchant ships, could we please keep the thread on topic? Thanks.

[Nikademus]

ORIGINAL: RAM

If Nikademus happens to read this he may ellaborate a bit more, he's a true BB and BC nut .

I could, but as the thread originator has reminded all, this thread is about Merchant durability.....an issue on which i have mussed about in the past. So out of respect to him i wont go into novel mode about HMS Hood [;)]

[Chris21wen]

Got a picture of her over my desk, before she was sunk though[8D]

[Chris21wen]

A useless fact. The Hood (262m) was only 1m shorter than the Yamato (263m).

The mighty (or not so mighty Hood)

[Chris21wen]

Forgot the photo.

[Chris21wen]

During the war there were many instances of tankers suffering enormous amouts of damage but still making it back to port. One to the most famous incidents was a Med convoy from Gibraltar to Malta. SS Ohio (Yes American) see the picture if her entering Malta.

[RAM]

ORIGINAL: Panzer76

My question was primarily about merchant ships, could we please keep the thread on topic? Thanks.

My apologies, Panzer76, I just wanted to answer an OT comment with an OT answer (as I already said in my previous message). I wanted to discredit the common relationship set between Hood's sinking with the fact that she was labelled as Battlecruiser (even while she was better armored than many battleships of 1941), a common, but wrong, identifier for "lightly amored heavy armed ships".

I didn't meant to change the topic of the thread at all, just put some things straight. As you said this is a thread to discuss the merchant ship ability to stand punishment in the game, not to discuss why the HMS Hood went under .

[Feinder]

The Hood's lesser amount of deck armor has been greatly maligned thru history.

A lucky shot, that happend to penetrate the "right" spot.

Some points to ponder...

1. What they mean by "speed is the best protection" -was- a sound philosophy at the time of her construction. The battle of the Faulklands (1914?), was dictated by the superior speed RN BCs, where they soundly clobbered their German opponents. Jutland showed otherwise, but it certainly presented a conundrom to designers of the time.


2. It might very well have been the Prinz Eugen that sank the Hood. With the Hood having only 2 - 3" of deck armor, the 8" shells from Prinz Eugen could very easily have penetrated even 3" of armor.


3. -NO- capital ship (up until Dakotas and Iowas, and the overall "beasts" that were the Yamato and Musashi) has ever been sufficiently protected from "plunging fire". Plunging fire occurs after about 12,000+ yds, and means that the trajectory of the shells are such that they are essentially falling like rain, instead of "direct fire", where the shells impact latterally against the ship. Pluging fire is normally against the deck (top) armor of a vessal, wherease "direct fire" is against the belt (side) armor of the ship. The general rule of thumb (that was used up to, and throughout WW2), was belt armor should equal gun size, and deck armor was about 1/4 - 1/3 of belt armor. So a ship with 15" guns would have 15" of belt armor, and 3 - 5" of deck armor. The reason for the lack of deck armor included :

a. at the time that most BBs were constructed (1910 - 1920), fire control was still quite difficult (no radar). Therefore, an egagement was EXPECTED to be at ranges of <10,000 yds, where the visible fall of shot could be most accurately observed. We point back to belt armor (direct fire) being the main concern at ranges of less than 10,000 yds; because "What's the need for greater deck armor, if nobody is likely to hit anything at ranges where deck armor is the considered factor?"

b. If you don't need much deck armor, because you don't think surface engagemenst will be over 10,000 yds, your only other threat is Gen Billy Mitchell and those new-fangled flying machines. Everybody knows that Mitchell got lucky sinking those two obsolete German BBs, but we'll put enough armor up top to protect vs. most bombs that planes can carrry (about 250 lbers during the 1920s).[/sarcasm off]

c. The real threat was considered to be torpedoes (actually, quite accurate). Most capitol ships were refitted with torpedo bulges, or incorporated them into their design.

d. All this armor means weight. The more amor you have, the more weight you now have to push thru the water. You either need more/stronger engines, but if you do that, you now have to spread your your armor more, to protect those extra engines (cue the Hood). Or you squish everything together (less area to protect), but your limited to fewer, less powerful engines (the Rodney and Nelson were "squished" (very dense armor), but could only make 22 kts at best).


4. With it's 4 inches of deck armor, even the Prince of Wales was vulnerable to plunging fire from Bismark's 15" guns at those ranges. Conversely, Bismark would -ALSO- have been vulnerable to PoW and Hoods plunging fire (if they had hit), even with her 5" of dect armor.


5. Esp with the integration of radar into fire control, surface engages were able to "open" at much longer ranges (about 16,000 yds). This meant that Deck Armor -was- important. And it often only took 2 or 3 hits at such a range to decide the victor in the battle (if you've already lost 2 turrets by the time the range is within 12,000 yds, you're at a distinct disadvantage).

Enjoy.
-F-

[Nikademus]

ORIGINAL: Chris H

During the war there were many instances of tankers suffering enormous amouts of damage but still making it back to port. One to the most famous incidents was a Med convoy from Gibraltar to Malta. SS Ohio (Yes American) see the picture if her entering Malta.

An empty tanker in particular can be very durable to underwater damage due to multiple sealed compartmentation. However a loaded tanker is much more vulnerable and the risk of explosion greater. The Ohio of course was a notable exception and a tribute to tenancity of her crew.

Regular cargo carrying merchants, unless carrying ammo, are at less risk of explosion but their compartmentation and crew proficiency would be far below that of a naval warship. The risk of fire is also of major concern.

[Brausepaul]

I hesitate to take guncam movies into account. The guncam movies one can see nowadays will only show scenes where something cool is happening, no need to show a clip where a fighter pumps lead into a freighter to no effect.

On a sidenote: a similiar discussion came up with the introduction of American fighter planes in IL2 Forgotten Battles. Lots of US players complained about ineffective .50 caliber ammunition, claiming that there are so many clips showing exploding Zekes etc...but you will never get to see the uninteresting movies.

[tsimmonds]

However a loaded tanker is much more vulnerable and the risk of explosion greater.

Actually I believe an empty tanker would have a greater risk of explosion. It is not the oil that ignites, rather it is the volatile fuel vapor that is the product of evaporation. If the tanker is full, there is little space for vapor to occupy. If the tanker is empty of heavy fuel, it is full of vapor, and very susceptible to explosive ignition. This is also why empty grain silos explode, they are full of dust which is extremely explosive, while whole grain at worst becomes popcorn.

Another consideration is the tendency of liquids to absorb shock from underwater explosions. The bubble of incandescent gas released by an explosion tries to expand outward equally in all directions, until it finds a path of least resistance. Then the energy tends to rapidly transfer in this new direction. In the case of an empty tanker, this direction will tend to be be into the hull of the ship. In the case of a full tanker, this direction will be up into the air. Of course the ship will be holed in either case, but in the first case the internal damage is likely to be far greater than in the second.

[Nikademus]

That is a good point (on the vapor issue) but accounts seem to support the greater vulnerability of loaded tankers over empty ones, probably due in part to the fact that empty tankers often fill the storage compartments with water when returning to the point of origin (termed sailing in 'balast')

[Feinder]

Irrelevant...

Bingo.

Gas burns. Fumes explode.

-F-



Nik - Didn't know they did that! Interesting stuff! I just figured they probably wouldn't sail around empty, the'd find something to put in the hold for the return trip. I suppose water is an option! But wouldn't that be a bad idea, because now your taiting your storage area? Wouldn't that be problematic to have to clean the area out to be able to carry fuel or oil cargo next time?

[tsimmonds]

ORIGINAL: Nikademus

That is a good point (on the vapor issue) but accounts seem to support the greater vulnerability of loaded tankers over empty ones, probably due in part to the fact that empty tankers often fill the storage compartments with water when returning to the point of origin (termed sailing in 'balast')

In that case the most vulnerable condition I guess would be partially full.[;)]

I do know that some captains were often reluctant to ballast tankage spaces with sea water because of the contamination issue. The 3 DDs lost in Halsey's second typhoon were all low on fuel. Tanks that were empty should have been balasted with seawater for stability purposes, but they were not, due to the captains' reluctance to contaminate the tanks, knowing that this would mean a further delay before they could fuel.

[Adnan Meshuggi]

for shinano, she had been lost with only one torpedo, they had NOT built in the water defence system, so one hole and the ship is doomed.... can´t say this had been different if these things had been built in, but i bet yes, cause of the heavy damage her both bb-sisters took without sinking (both had been losses to a jamming rudder and failed counterflooding...otherwise they could have needed even more damages)...

[Nikademus]

sorry to go OT....but Shinano was hit by at least four torpedoes, not one [;)]

[tsimmonds]

ORIGINAL: Nikademus

sorry to go OT....but Shinano was hit by at least four torpedoes, not one [;)]

I think he's thinking of Taiho, a single torpedo hit leading eventually to massive and fatal detonation of fuel vapor....

[marc420]

From what I remember of my reading, historically tankers were rather difficult to sink. Even loaded, those individual, sealed off compartments tended to limit damage to just the compartment that was hit. But that's just a memory from reading books about submariners many years ago.

Seems like most merchants (non-tankers) aught to be pretty torn up from any decent size bomb or shell that gets a good direct hit.

As for the Hood, a critical hit system aught to take that into account. Perhaps with some extra cases for ships with idiotic designs that left the magazine vulnerable to plunging fire. But yes, for the Hood, for the Arizona at PH and some other cases, there should be a chance for that one shell, bomb or torpedo completely blows up the ship. There should also be critical hit cases that allow for what happened to the Bismarck ... ie one lucky torpedo hit which didn't kill the ship, but did make it uselessly immobile.

[steveh11Matrix]

I have several times already seen "*MAIN MAGAZINE EXPLOSION*" results. Ought to have been instantly fatal, but they seem not to have been, regardless of the size of the 'victim'.

Merchant ships: Remember the "Ohio", that stayed afloat just long enough to get into Valetta, enabling the defence of Malta to continue? Always been one of my favourite sea stories.

Steve.