How would you have avoided the attack on Pearl Harbor?

It wasn't just Kimmel, but Richardson, Kimmel, Stark, et al. However, reality is quite different. There is no meaningful long-range air reconnaissance being flown, and there is no inter-service cooperation to rectify this terrible oversight. Then, you have the US Army operating it's RADARs only briefly during the mornings, and lacking in an efficient method of coordinating the information received from the RADAR sites. So, the US admirals are worried about torpedo nets interfering with a speedy deployment, while lacking the tools necessary for raising the alarm that would result in this speedy deployment.

So, yes, torpedo nets would have mitigated some, or maybe much of the damage to the battle fleet at Pearl Harbor.

Incorrect, it was the "depth" issue that was the major deterrent in US thinking of a torpedo attack. As per Admiral Stark's February 15th 1941 memo to Admiral Kimmel

If the US assumed arming distance of 200 yards is "taken as gospel", that would be a point about midway between the shortest distance between "Battleship Row" and the shoreline. If the arming distance is altered, as Stark's memo cautions, that would place the point even closer to "Battleship Row". Thus, according to the US, arming distance would NOT prevent a torpedo attack.

Hardly surprising, as it was the easiest approach route to fly. It was a long uninterrupted approach over water that allowed for plenty of time to line up on either Oklahoma or West Virginia. However, by taking the shortest route there would be a lot of interference(turbulence generated by the buildings of the submarine base & supply base, several rising & falling air currents as the plane flew over colder water & warmer land masses) and precious few seconds to line up on the battleship target, achieve proper drop height & speed, before finally dropping the torpedo.

That is open to debate. There had long been strong anti-Japanese/anti-Asian racism in America, although it was more prevalent on the West Coast. Whereas, Germany was liked and admired by some of the more important Americans of the day. Japan was seen as the most likely threat, because of their location to American interests in the Pacific. Whereas Germany posed no "direct" threat to American interests, and to an extent, was in lucrative business partnerships with several American companies. So, I would think that it require much less "provocation" to get a DoW against Japan than it would to get a DoW against Germany.

 

Abour the idea to shield the BB with other, less valuable ships. Could it work? Different ships have a different draft. IIRC torps past underneath two ships(Vestal, Oglala) moored to other ships(Arizona and a CL?).

 

I believe I read somewhere that just prior to PH the decision had been made to use torpedo nets around the battleships. Given another month or 6 they might have been in place.

 

The supposed "torpedoing" of the USS Arizona has always been a matter of debate. IIRC, no proof of this hit was found during several underwater surveys of the ship. However, the torpedo that passed underneath the USS Oglala is well known.

As to the "effectiveness" of sacrificial ships is, IMHO, a matter of opinion. The USS Oglala and the light cruiser USS Raleigh(CL-7) had roughly the same draft. Yet, one torpedo passed underneath the USS Oglala, and one torpedo targeted at the USS Raleigh didn't. I would suppose it would be somewhat helpful, but OTOH, also wasteful. By not doubling up the battleships, you would need eight "sacrificial" ships, plus another three or four to "protect" the carriers when they are in port.

Overall, torpedo nets are the more sensible, sane, and cost-effective way of defeating torpedoes.

But, to attempt either option, one must first recognize that the danger exists and is likely to occur.

 

This is B.S. from Kimmel, either he's blowing smoke after the fact, or truly ignorant.

Battleships of the day couldn't get underway in a hurry regardless of torpedo nets, they needed an hour or two (at least) to build up steam in the boilers before getting underway.

That was the reason that the British started the attack on the French fleet in Mers-el-Kebir, the French BB's were seen to be firing up their boilers, the RN needed to attack right away, or else the French could sortie after a couple hours.

So as soon as the order is given to fire up the BB's boilers, there is at least an hour to remove nets, move outboard ships etc.

Wouldn't the "War warning" a week or so earlier be enough reason to take precautions?

True, it would be better if the outboard ships were deep enough.
But what depth were the torpedoes set at? (for the expected possible targets at PH)
The US BB's ranged in draft from 29.5 - 33 feet, the Lexington & Saratoga 24 feet, Enterprise 26 feet.
IJN wouldn't want to have the torps deflect off the keel, so they would likely be set at 15 - 20 feet.

,
Did they have nets available before the attack? Certainly it would be foolhardy not to deploy them if available.
If they weren't they could certainly moor the less valuable ships outboard until the nets were set up.

Utah is the same draft as the other BB's (as it's a near sistership), in fact it was at Pearl, but wasn't moored along Battleship row, it was moored on the opposite side. (Although it was identified as a BB by Japanese pilots, who put a couple torpedoes into her anyways)
And while a light cruiser would be too shallow (at about 16') there were several suitable ships available.
USS Wright was a seaplane tender based at Pearl, it had a draft of 23.5'. The Cimarron class oilers were 32' deep, while there were other repair/depot ships of similar draft.

 

My understanding is that the battle fleet standard for "flushing" Pearl Harbor was one and a half hours. Furthermore they apparently met it on several occasions.

 

Indeed, that was my understanding too.
What I should have written was "One to two hours (*or longer)".
"Or longer" would depend
on how long it took for Kimmel's orders to get to the ship(s)

But they would still need to bring the other boilers up to provide full steam if they were to sail fron harbor, correct?
With only 1 or 2 boilers hot the ship would have limited speed possible.


In any event, I think the point that I was making is that a responsible commander should be taking some precautions if an attack was possible (even though unlikely)
If it would take 30 or 60 min to remove torpedo nets, so be it.
If the torpedo nets are not ready, place other ships outboard.

A responsible commander should also be considering "what if they did" rather than "I bet they won't"

 

Obviously, the most important precaution would be having AA gun crews trained, alert & ready and having your radar up and running.


Here's an interesting photo from '42 or '43 of the RN at Gibraltar for comparison.
Hard to tell, but It looks like HMS Renown, a Nelson class BB and a QE battleship (probably Malaya)

They are moored out on the mole rather than along the landward side, which would presumably prevent torpedo attacks from the western side. (and it would be almost impossible for an attacking TB coming from the east, as it would have to fly over the rock, then dive 1,000 feet to get to torpedo launching depth.


View attachment 15734

 

USS Nevada needed ~50 minutes to get underway. I assume she was at the same state of readyness as the other ships. So if it had taken 30-60 minutes to get anti-torpedo net out of the way, that would have been a minimal delay at worst.

 

OP, are you sure about the date on that photo? The ship anchored out at far left looks like Hood, then there's the other Nelson, and what appear to be at least two R class, besides the ships at the mole. None of them appear to have the new superstructure or hangars fitted to most ships modernizedin the 1930s. This looks like a major concentration, perhaps a pre-war exercise?

 

There is also the question of building up steam for departure vs an emergency move.
IIRC the Nevada had 6 boilers (as did Penn & Arizona), so if 2 were hot she could limp along at 10 - 12 knots, enough to get out of the harbour, but not for full power, (I would think?)

Freebird's photo.

It was tagged as Gibraltar WWII, but it could be wrong. It's tough to see the detail in the pic.
I was looking for phots of other ports in WWII to see what kind of mooring arangements were used.

This one was labelled Malta 1943, is that a KGV class in the foreground?
The Grand Harbour in Valetta is much narrower than Pearl, and they had loads of AA at the ready.

Of course one of the differences is that the in the ETO the Italains & Germans used Ju88's and other 2 or 3 engine craft to drop torpedoes, they didn't have a single engine aircarft like the Kate. (Ju87's were not used to drop torpedoes IIRC?)


The question that I'm bringing up here would be what reasonable measures would be prudent for a port commander after getting a "war warning" but when an attack there wasn't considered likely.

Gibraltar was a little to far for major Axis attack, but did get a few nuisance raids, and was attacked by the French in 1940.
Malta on the other hand was attacked intensely during the war, although by late 1943 wouldn't have been in much immediate danger either. View attachment 15736

 

re: Declarations of War??--

>[Takao] I would think that it require much less "provocation" to get a DoW against Japan than it would to get a DoW against Germany.<

Speculation unwarranted. You are talking about WAR, where a reluctant America would send its dearest generation off to die. War, where sacrifice and suffering are the order of the day. No country is going to take that step without SEVERE provocation. *BECAUSE* our own interests in Asia were of lesser importance than in Europe, because the territory to be fought over were COLONIAL interests of rotting empires, and BECAUSE we were still in negotiations (whether they were temporarily broken off, as the Dec. 7th diplomatic messages would indicate), and BECAUSE the act of going to war was so reprehensible without just cause, I would take the position that ONLY a direct attack on American territory (and I fully believe Guam, the Philippines, etc., just BARELY qualify, being recent additions within the lifetimes of most of the adult population of America) would precipitate an actual WAR with the Japanese. America did NOT want to send its sons to die for "familiar" European countries, much less European COLONIES in far-off Asia.

>[Takao] Germany posed no "direct" threat to American interests, and to an extent, was in lucrative business partnerships with several American companies.<

America certainly had more "interests" in Britain, Scandanavia, Benelux, France, etc "going under" the crushing thumb of Germany that may have BEEN lucrative before the war, but certainly NOT after war had imperiled these under the Nazi banner.
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On a different subject (anti-torpedo nets), why not "net-ships"? That is, instead of buoys holding the nets, actual "trawlers" anchored with nets strung and weighted between them, so they could hoist anchor and MOVE themselves away enough for their brood to pull out, and very quickly. A small fleet of these would enable torpedo protection AND quick re-positioning.

Re-iterating, WHAT MEASURES DID PEARL HARBOR INITIATE *AFTER* THE ATTACK TO MITIGATE POTENTIAL SUBSEQUENT ATTACKS FROM ACCOMPLISHING THE SAME THING AS THE FIRST ATTACKS?? NOTHING??

 

Post-Attack Measures:

Sure, OP, I remember those ARMY measures for preparedness. The radars were JUST getting installed and barely operational on Dec. 7th, so getting more "advanced warning" was appropriate. "More guns ready on the ships.."?? That would seem appropriate, too, but my main question is what measures did the NAVY take to protect their fleet in harbor POST-attack that could have been done PRE-attack?? Naturally, the damage to BB Row was already done, but when you consider what another attack could have done a month or so later when some of the blocked battleships were freed....? My main question relates to attack-mitigating measures put into place afterwards, with hindsight. *IF* there was nothing much done post-attack, MAYBE there really wasn't much the Navy could have done (or they were just fools?) pre-attack, despite our suggestions/accusations. If significant changes were made re:berthing, positioning, torpedo nets, etc., what were they, and is there a record of the plan to do so??