Operation MO July 1-14, 1942
Operation MO July 1 to July 14, 1942.
Japanese plans.
Order of battle:
Carriers: Zuikaku (F), Ryujo and Junyo.
BB's: Kongo and Hiei.
Cruisers: Div 6: Aoba, Furutaka, Kako and Kinugasa
DD's about 20
Transports for the Aoba detachment.
Orders: The carriers will suppress any planes/assist Aoba at Port Moresby and then Zuikaku & Ryujo are to move south and south-west to intercept any reaction force. The BB's are included with them. Junyo's planes are to be included in scouting. (The mistakes at Midway is causing this change to SOP.)
The transports will land the Aoba near Port Moresby. Then Aoba will move overland to Port Moresby and attack. Seizing the airfields at Port Moresby is the inital goal. The Cruisers are to provide fire support.. (Again Midway is causing this change to SOP.) Junyo's air group is to occupy the captured air field
ON/about july 21 Zuikaku & Ryujo are to proceed to New Caledonia and raid/scout the island on/about july 28. The BB's are to follow Zuikaku, unless circumstances dicate a different role.
Why the raid on New Caledonia? Japanese intell/data on the island is months old. Given the bad data at Midway, The Japanese Navy wants some fresh data for operation FS. Also, the last two Japanese OPS that had “Surprise” (Coral Sea & Midway) and did not work the way the Japanese planned. Also, Victory Disease here, “Surprise” may not be an operational necessity anymore. It was needed when the US Navy had most of its fleet, but now? Japan has the superior fleet, “surprise” isn't needed.
Also, steming from the Japanese Victory disease, The Japanese Navy wants the US Navy to respond to there actions. By Telegraphing that New Caledonia will be the next major target, the US Navy must respond, or by Japanese standards “lose” the war. The Japanese want to “win” the war by sinking the remaining capital ships of the US Navy, not just frighten them away.
The Aoba detachments plans? Land, move to Port Moresby and attack. They have some maps from previous photo overflights. They plan on 1 day to land/organize on beach and move out. Day 2 to move into position. Night Day 2/Day 3 attack Port Moresby. (yes, pretty much what Ichi planned/did on Guadalcanal)
Hmmm. This is about as good a place as any, so.
Generally speaking, in order to win, the more you outnumber your opponent the better your chances. Generally, you wanted at least twice the number of your oppenent to win.
Japanese Army SOP.
Beginning with China, the Japanese army has used small assualt forces and WON. They would send forces 1/2 or less against opponents and succeed. Until the US/Allied forces can crush these small Japanese detachments and do it in way that the Army can not blame something else, the Japanese Army will continue this policy of using small assualt forces.
For example. The destruction of the Midway assualt force is dismissed due to the approach/ground/reefs at Midway.
So, the proven, successful, plan of landing and then moving into combat will be used in MO and, planned for FS.
Allied Plans.
US Navy. Pearl/DC. Nothing special. They plead Midway and lack of resources.
Australia: Task Force 44 w/attached DD's/escorts to move south and south-west of Port Moresby. Adr Crutchley orders are to protect Port Moresby to the best of his ability. A reinforcing convoy is assembling at Townshead and by July 1 is enroute to Port Moresby. Task force 44 & convoy will be held away from Port Moresby during battle. They are hoping for an opening to make a run to Port Moresby and land forces/supply.
MacArthur: Moving forces to Townshead to be transported to Port Moresby. He is not going to retreat again!
Operation MO. Events my timeline.
As the Japanese fleet approaches Port Moresby scout planes notice the new, and prviously unknown, base at Milne Bay. Overflights guess “a couple of hundred men”. A destroyer approaches and fires at Milne Bay. The 2 3.7” AA guns fire back. No real damage on either side. Aoba detachment is ordered to eliminate Milne Bay, after it has conquered Port Moresby.
Landings/Air actions July 7, 1942
Port Moresby's defenses:
Port Moresby according to Wiki aircraft assigned.
40th fighter (p39's) This squadron has been in the area since late april/early june. Judging by other data, during this time period, after a month or so, operational fatigue sets in and the effectiveness of pilots/planes drop. So...limited # of planes & fatigue/stress that limits effectiveness
80th fighter (p39) wasn't there until july 20. New Squadron rushed into combat before training was complete. Effectiveness?
75th Raaf fighter (p40) wasn't there until late july (it was there earlier in apr/may but was withdrawn and reformed in may/june/july) Experienced pilots returning to area. The best squadron in area.
76th Raaf (p40) first action in late july. New squadron rushed into combat before training was complete. Effectivenss?
How many planes? Since three squadrons was rushed forward... maintaince would be rushed/minimal. So flyable... Call it 60ish flyable.
Zuikaku 27 zero, 27 val, 18 kate.
Ryujo 24 zero. 9 val, 6 kate
Junyo 18 zero, 18 val, 9 kate
totals 69 zeros, 54 val, 33 kate
Junyo is the newest carrier and her air group has experience from Alaska.
Zuikaku air group was just reformed after coral sea. First Op since.
Ryujo air group was reformed in may 1942. They have experience from Alaska.
The Japanese are planning mult ops for the 3 carriers. Aoba detachment is supposed to take MO. The Navy role is support, so, between limited experince on the Japanese side and a belief that Aoba will take MO with minimal support, the carrier air groups aren't going all out during MO. As long as the Allied planes are NOT attacking Aoba, the Japanese Navy believes it has done its job.
Also. Even under perfect conditions, the Japanese Army and Navy did not work well together. There is no SOP for Aoba to direct attacks.
Many/some Japanese Pilots removed, to save weight, radios from their planes and watched their squadron leader for tactical instructions.
The air battle of July 7.
Due to the inexperience/limited training of half of the allied planes/problems coordianting/weather (partly to full clouds), the Allied fighters meet the Japanese in small section/division groups, not in a large group.
The Japanese, which also had problems with the weather but stayed together by carrier group, then, had numberical superority during encounters.
Allied loses: 20ish crash landed/out of action. Most of the rest with some damage.
Japanese 10 zeros down. 6 val, 4 kate.
Effectiveness of Japanese air attack?
Minimal damage.
Japanese cruisers approach and begin shelling of Port Moresby.
Effectiveness? Some, call it medium damage. With their scout planes occupied dodging Allied fighters, they can not direct the shelling. (Aoba and Kako lose their scout planes today, during the week all the cruisers lose their planes.)
BUT, between them, this did distract Allied command, so Aoba's landings, a few miles away, was unopposed.
Other Allied air forces:
Allied B-17's, A-20's, PBY's and RAAF Hudsons do attack on a daily basis during this battle. And, while these bomber units later in the war develop tactics like skip bombing this is before that happens. So, attacks are as trained. High/medium level bombing.\
During this time period, they claim to heavy damage and/or sink a “large” carrier, a BB, a couple of Cruisers, and 4 DD's and 4 transports.
Actual damage: 2 Transports sunk. 4 transports damaged. 1 DD heavily damaged. 1 cruiser medium damage. Light damage to all three carriers. (near misses that sprung leaks/shrapnel)
Air battle July 8
Nothing. Bad weather.
Ground forces
Aoba approaches Allied defensive lines. Bad weather/minimal maps causes delays.
Air battle July 9
more bad weather limits flights.
Allied 5 lost
Japanese 1 zero, 1 val, 1 kate
all lost due to operational reasons, not combat.
Ground forces
Aoba night July 9/10 reaches Allied defensive lines.
Dawn July 10 Aoba attacks Allied lines. Aoba withdraws after 300-400 causalities.
Air Battle July 10
Allied 10 lost
Japanese 2 zero 3 val.
Ground forces
Night july 10, Aoba retreats and begins to move around Port Moresby. Obviously, they hit a strong defensive position with their first attack, so, they are moving around until they can find a weak spot. During the next few nights, the Japanese launch company sized probing attacks. They lose another 200-300 during this period.
During this time,Aoba is repeatedly told that the carriers have other duties planned and he must attack and win so they can leave.
Air battles July 11-14
Minimal action. Without any real clue where Aoba is, the Japanese send only high level bombing directed at the airfield.
Allied: 6 lost
Japanese 1 val, 2 kate.
Dawn July 14
Aoba attacks again. They leave 200 dead before retreating.
Aoba radios that they are so weakened, due to combat losses/supply problems (out of ammo and food, they only brought what they could carry) that they can not attack again.
Recap/after action report.
Allied ground forces loses: about 200 dead/400 wounded.
Allied planes: 50ish shot down/crashed landed. However, repair work means they have 10 to 20 flyable fighters, depending on your definiation. Most of the p-39's are gone, only 5ish still flyable.
Japanese
Aoba: over a 1000 dead. Many more wounded. It moves to the nearest coast and rests. It's offensive abilites are gone. Defensive?
Carriers:
13 zeros lost in combat. wrote off another 8. leaving 49 flyable.
11 val lost. wrote off 7. 36 flyable.
7 kate lost. wrote off 5. 21 flyable
About 1/3 of the total planes lost.
Navy casualites: 200ish, mainly from a DD that took a bomb.
The end of the Battle of Port Moresby (july 7-14, 1942)
Thank you for reading.
Jeff shelton