A massive torpedo attack would have been the end of the U.S.S. Iowa. All classes of Japanese detroyers were rather thin-skinned and a few five inch hits should do it. However they had a lot of 'long lance' torpedos that were accurate, long range and had a big bang. The Iowa would have been severely disabled, then sunk, dead in the water.
Surface fights never go as expected. The fog of war seems very thick on the water. However, in this isolated match-up twenty attackers would overwhelm the mighty Iowa.
P.A.
Torpedoes in the water and hitting are two different things.
The Iowa class battleships were the fastest ships in the water with the exception of destroyers.
Here is an assessment of torpedoes on an Iowa class battleship.
Strafford Morss and Iowa Class Survivability
Commander Strafford Morss wrote an article in 1984 on the survivability of the Iowa class agaist modern weapons. It is to long to post everything but I will place in quotation marks those areas that are in the article. He first takes on to
" The following evaluations are estimates of the damage to be expected by an Iowa class ship. The shock wave from an underbottom proximity explosion assumed to be at least 1000 pound TNT will be absorbed partially by the triple bottom structure. Forward in the area of Turrets 1 and 2, storerooms below the powder magazine could be flooded and flooding of the magazines less likely. Detonation of the powder magazines would be unlikely.
Beneath the machinery spaces it is assumed the triple bottom will be breached. Depending on damage location one and no more than two machinery spaces would flood. With the alternating fire room engine room no more than one shaft would be affected. This was the intent of the designers.
Farther aft the two skegs supporting the inboard shafts should help resist underbody damage however the outboard shafts remain vulnerable. The ship has a full void under the ram room three to six feet deep and has better protection than did Bismarck. Some directional control is possible with propellers alone. However the rudders are the most difficult area to protect in any ship.
Forward of the armored citidel there would be concern as to the possible loss of her bow however some reinforcement of the bow has occured during the years of active service.
A contact side explosion is expected to result in damage similar to that recieved by North Carolina.
In no case should a single hit be fatal to the ship. but each subsequent hit will increase disruption and reduction in capability making it more difficult for the ship to continue." end quote.
"Shape charges torpedoes are expected to breach the system but will cause less damage to shell plating. Shape charges torpedo warhead tests on a side protective system based on an aircraft carrier did produce fragments that penetrated the holding bulkhead however this system did not have an armored bulkhead. However, if within range of her objective, she should still be able to employ her missile and gun batteries even with grievous underwater damage" end quote.
In no case are we speaking about the total structural failure of the ship. I would add shock damage could be considerable but she does have redundant systems so her ability to recover after damage remains high. Basically what happens is the triple keel absorbs as much of the energy it can and then breaks venting the explosion into the ship. A single torpedo can not damage enough of her structural strength so the keel is crushed locally with the sides of the ship holding her from hogging in any significant way. Her upper strength decks being so strong there is no significant sagging motion either. Therefore you get localized flooding similar to a side hit. This is why Arkansas remained intact despite a nuclear explosion below her keel. The keel is crushed all around her framing and side protection inwards into the hull. The shock wave was transmitted into her hull and two propeller shafts were ripped out. Despite being thrown into the air over two ship lengths or over 1,000 feet she never hogged. Her sides were keeping her intact as the keel was crushed and her armor is cracked in only one location on one side but not torn open. Though she slammed upside down onto the sea floor her upper decks show no sign of hogging or sagging. Her turrets remain in their barbettes and her casemate guns and battery deck are unaffected. One side is crushed flat as the sea fell back on top of her but the type of structural failure you see with small destroyers taking a torpedo under the keel does not apply to an Iowa or a large carrier. I can not think of a more extreme test to demonstrate this. The Baker bomb was tens of thousands times more powerful then a single conventional torpedo and could not produce the type of structural failure seen in small warships.
