Pearl Harbor Defense

"John Carrier" wrote in message ...
I think the single biggest undone defense would have been torpedo nets, but
the reality was no one thought torpedoes could be used effectively in Pearl
Harbor's shallow waters.

The US Navy had fallen well behined in torpedo technology. For
instance the IJNs Japanese Navy Long Lance Torpedo could manage 46
knots for about 22 knautical miles and 35 Knots for about 36 nautical
miles. It had 50% more speed and 10 times more range. It used pure
oxygen not air and didn't usually leave a trail. When under attack by
Japanese subs the Americans sometimes thought they were being attacked
from multiple directions when in fact a single Japanese sub had fired
through their fleet to the other side!

The problem was eventualy traced to the USN rotating its staff through
its torpedo division every 2 years or so thus it never developed any
expertise in developing torpedoes or envisaging what the enemies might
be capable of.

It must have been the same for aircraft lauched torpedoes. The
Japanese ones presumably being better in every aspect such as launch
height, speed, range and minimum depth.






Buttoning up the ships and manning battle stations would probably have
helped to some degree. A combination of some opposing fire and some aerial
opposition would have had an impact on the success of the strike ...
probably more in line with Japanese expectations in terms of impact on the
fleet.

I don't think the returning CV's could have accomplished anything of
significance. Worst case would be have been to find the Japanese ...
because they in turn would have been found and likely destroyed.

I think 30 minutes lead time would be insufficient to sortie the fleet ... a
good thing considering the likely outcome had they been caught just clearing
Pearl and entering deeper water.

R / John

..... the IJNs Japanese Navy Long Lance Torpedo could manage 46
knots for about 22 knautical miles and 35 Knots for about 36 nautical
miles.

Impressive but is there even the slightest chance of hitting a ship
22 nm away?

vince norris

vincent p. norris wrote:
..... the IJNs Japanese Navy Long Lance Torpedo could manage 46
knots for about 22 knautical miles and 35 Knots for about 36 nautical
miles.


Impressive but is there even the slightest chance of hitting a ship
22 nm away?

Sure, if it's at anchor. A common tactic on all sides was lying off an
anchorage and plinking the sitting ducks. The Japanese could do it from a lot
farther away, though.

--
Marc Reeve
Some guy at a desk somewhere ^reverse^ for email

vincent p. norris wrote in message . ..
..... the IJNs Japanese Navy Long Lance Torpedo could manage 46
knots for about 22 knautical miles and 35 Knots for about 36 nautical
miles.

Impressive but is there even the slightest chance of hitting a ship
22 nm away?

The Type 93 or "Long Lance" had this 40,000 meter range. It was
however a large ship launched torpedo. The Type 95 was a reduced size
version of the "Long Lance" with a range of 12,000 meters designed for
submarine use. For giggles it is worth mentioning that the US Navy's
surface torpedoes managed about 5500 yards and their submarine
torpedoes about 1800 at this time.

I expect a spread of torpedoes were fired such that at extreme range 6
or 8 torpedoes would be distributed every 100 meters or so for an
600-800 meter wide hit window. Don't forget a ship is likely to be
between 100 to 300 meter long.

The Germans had torpedoes that could run various types of zig-zag and
circling patterns either aimed at individual ships or designed to run
through convoys. The patterns were becoming more sophisticated as the
mechanisms improved. So presumnably if the range measure was wrong or
the target evaded the torpedo it could turn around and have another
attempt.

The deadliness of the u-boats was due to their aiming computer which
could compute 5 simultaneous firing solutions on seperate targets.
Hit rates of around 80% were common.

A combination of German and Japanese technology would have been lethal
I expect though who knows how good the japanese torpedoe guidence was?

US torpedoes tended to be less accurate perhaps due to the use aiming
by sonar due to the visibility of the subs at periscope depth.

The German Type XXI u-boat had the an array sonar that was unusually
accurate and capable of ranging (and thereby plotting and evading
attacking ships) german hydrophones were based on passive arrays
electronicaly processed and distributed around the hull and were far
more accurate and sensitive than allied ones. Sonar ranging both
active and passive allowed the Type XXI to attack without use of
periscope.




vince norris

On 15 Sep 2004 23:25:48 -0700, (Eunometic)
wrote:

The US Navy had fallen well behined in torpedo technology.

It was not just the performance specs, either. The USN torpedoes were
inacurrate, often running so deep that they passed under the enemy
ship. More than one American sub was sunk by its own torpedo. See
www.warbirdforum.com/okane.htm

Dick O'Kane (the subject of that book review) recalled that when word
went back to Washington about the faulty torpedoes, the brass blamed
the sub skippers for their tactics rather than examing the torpedo for
defects.

all the best -- Dan Ford
email: (put Cubdriver in subject line)

The Warbird's Forum www.warbirdforum.com
Expedition sailboat charters www.expeditionsail.com

It was not just the performance specs, either. The USN torpedoes were
inacurrate, often running so deep that they passed under the enemy
ship. More than one American sub was sunk by its own torpedo. See
www.warbirdforum.com/okane.htm

Dick O'Kane (the subject of that book review) recalled that when word
went back to Washington about the faulty torpedoes, the brass blamed
the sub skippers for their tactics rather than examing the torpedo for
defects.

The aircraft torpedos used by the TBD's were about as bad. There can be no
more harrowing thought than that of the TBD and TBF squadrons at Midway being
slaughtered making their runs to deliver torpedoes that tended to explode on
contact with the water.

Cub Driver wrote:

On 15 Sep 2004 23:25:48 -0700, (Eunometic)
wrote:


The US Navy had fallen well behined in torpedo technology.


It was not just the performance specs, either. The USN torpedoes were
inacurrate, often running so deep that they passed under the enemy
ship. More than one American sub was sunk by its own torpedo. See
www.warbirdforum.com/okane.htm

Dick O'Kane (the subject of that book review) recalled that when word
went back to Washington about the faulty torpedoes, the brass blamed
the sub skippers for their tactics rather than examing the torpedo for
defects.

Until Dan Daspit gave them incontrovertable evidence...

While commanding USS Tinosa, Daspit came upon the Japanese oil tanker
(converted from a whaling factory ship) Tonan Maru #2. He fired two torpedos,
one of which exploded at the stern, leaving Tonan Maru dead in the water. No
escorts being evident, Daspit surfaced to finish her off. Torpedo after torpedo
was fired, with result varying from clean misses, to circular runs, to clean
hits that did not explode. In all, Tinosa fired 12 torpedoes at a stationary
target, of which none functioned as designed.

Fortunately, Daspit had a movie camera on board and filmed the whole operation.
The film caused some consternation back at Pearl.
--
Marc Reeve
Some guy at a desk somewhere ^reverse^ for email

Cub Driver wrote:

On 15 Sep 2004 23:25:48 -0700, (Eunometic)
wrote:


The US Navy had fallen well behined in torpedo technology.


It was not just the performance specs, either. The USN torpedoes were
inacurrate, often running so deep that they passed under the enemy
ship. More than one American sub was sunk by its own torpedo. See
www.warbirdforum.com/okane.htm

Dick O'Kane (the subject of that book review) recalled that when word
went back to Washington about the faulty torpedoes, the brass blamed
the sub skippers for their tactics rather than examing the torpedo for
defects.

The problem was with the magnetic fuses. Again, the dimwits in charge
refused to do proper testing. The tests were expensive and the Navy
knew that their white engineers had innate superiority to gooks. This
oversight, along with some strange attack doctrine, extended the war and
cost us some sailors.

On the other hand, the Navy's analog computer (TDC), used for solving
targeting problems, was quite good.

Cheers.

--mike

all the best -- Dan Ford
email: (put Cubdriver in subject line)

The Warbird's Forum www.warbirdforum.com
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