Midget submarine operation Attack on Sydney Harbour

1 midget submarine operation

1.1 final reconnaissance
1.2 plan of attack
1.3 attack

midget submarine operation
final reconnaissance

before dawn on 29 may, i-21 s floatplane performed final reconnaissance flight on sydney harbour, mission of mapping locations of major vessels , of anti-submarine net. multiple observers spotted floatplane assumed navy curtiss seagull. no alarm raised until 05:07, when realised ship in area carrying seagulls u.s. cruiser chicago, , 4 of aircraft on board. richmond air force base launched raaf wirraway fighters, failed locate i-21 or floatplane. therefore, reconnaissance flight did not result in authorities in sydney taking special defence measures. floatplane damaged on landing , had scuttled, both aircrew survived.

plan of attack

the japanese planned launch midgets 1 after other between 17:20 , 17:40, points 5–7 nmi (5.8–8.1 mi; 9.3–13.0 km) outside sydney harbour. first midget pass through heads after 18:30, heavy seas delayed on hour. other 2 midgets followed @ twenty-minute intervals , delayed.

the choice of targets left midget commanders, advice should target aircraft carriers or battleships, cruisers secondary targets. midgets operate east of harbour bridge, although if no suitable targets found in area move under bridge , attack battleship , large cruiser believed in inner harbour. when second reconnaissance flyover revealed expected british battleship—hms warspite—was found, uss chicago became priority target.

after completing mission, midgets depart sydney harbour , head south 20 nmi (23 mi; 37 km) recovery point off port hacking. 4 of mother submarines waiting in east–west line 16 km (8.6 nmi; 9.9 mi) long, fifth waiting 6 km (3.2 nmi; 3.7 mi) further south.

attack

midget submarine m-14—launched i-27, first enter sydney harbour. middle head - south head loop detected @ 20:01, dismissed reading due heavy civilian traffic. @ 20:15, maritime services board watchman spotted midget after passed through western gap, collided pile light, reversed , trapped stern in net. submarine s bow broke surface; watchman rowed toward determine , rowed nearby patrol boat hmas yarroma report finding. despite efforts yarroma pass on information, sydney naval headquarters did not receive report until 21:52. hmas yarroma , lolita dispatched investigate. upon confirming object in net baby submarine , lolita dropped 2 depth charges while yarroma s commander requested permission sydney naval headquarters open fire. depth charges failed detonate, water shallow hydrostatic fuse setting. @ 22:35, while yarroma waiting permission fire, , lolita setting deploy third depth charge, 2 crewmen on m-14 activated 1 of submarine s scuttling charges, killing , destroying submarine s forward section.

muirhead-gould gave general alarm, along orders ships take anti-submarine measures, @ 22:27; alarm repeated @ 22:36 advice ships take precautions against attack, enemy submarine might in harbour. @ time of first alarm, sydney harbour closed external traffic, muirhead-gould ordered ferries , other internal traffic continue, believed having multiple ships travelling around @ speed force submarines remain submerged.

midget submarine m-24 second enter harbour. hmas falie grazed m-24 s hull , reported contact command. report not followed up. m-24 crossed indicator loop undetected @ 21:48, , @ approximately 22:00 followed manly ferry through anti-submarine net. @ 22:52, m-24 spotted chicago searchlight operator less 500 m (1,600 ft) moored cruiser s starboard, , on course parallel ship s facing. chicago opened fire 5 in (130 mm) gun , quadruple machinegun mount, inflicted minimal damage weapons not depress far enough. of 5 in (130 mm) shells skipped off water , hit fort denison s martello tower, while fragments later found in suburbs of cremorne , mosman. senior officer present aboard chicago ordered crew begin preparing departure, , uss perkins begin anti-submarine screening patrol around cruiser, orders revoked sceptical captain howard bode when arrived on board @ around 23:30.

hmas whyalla , geelong fired upon m-24 fled west toward sydney harbour bridge, before midget able submerge , escape. when returned periscope depth, midget found west of fort denison. turned , sailed east 1 nmi (1.2 mi; 1.9 km), took firing position south-west of bradley s head, commander see chicago s stern silhouetted against construction floodlights @ garden island s new captain cook graving dock.

midget submarine m-21—from i-22—probably entered harbour @ same time uss chicago opened fire on m-24. unarmed auxiliary patrol boat hmas lauriana spotted m-21 , illuminated submarine s conning tower, while sending alert signal port war signal station @ south head, , nearby anti-submarine vessel hmas yandra. yandra attempted ram submarine, lost contact, regained contact @ 23:03, , dropped 6 depth charges. @ time of attack, assumed depth charges had destroyed or disabled midget, m-21 survived. historians believe midget took refuge on harbour floor , waited until allied vessels had moved away before resumed attack.

at 23:14, muirhead-gould ordered ships observe blackout conditions. after 23:30, set off on barge towards boom net, make personal inspection. admiral reached lolita @ midnight , indicated crew did not take reports of enemy submarines seriously, reportedly saying: playing at, running , down harbour dropping depth charges , talking enemy subs in harbour? there s not 1 seen. crew reiterated submarine had been seen, muirhead-gould remained unconvinced , before left, added sarcastically: if see sub, see if captain has black beard. d meet him.

hmas kuttabul following japanese attack

despite blackout order, garden island floodlights remained on until 00:25. 5 minutes later, m-24 fired first of 2 torpedoes; delayed firing second torpedo several minutes midget submarines lose longitudinal stability after firing torpedo. historians divided exact paths of torpedoes relative chicago, although agree cruiser intended target. both torpedoes missed chicago, while 1 torpedo may have passed close perkins starboard bow. 1 of torpedoes continued underneath dutch submarine k-ix , hmas kuttabul, hit breakwater kuttabul tied against. explosion broke kuttabul in 2 , sank her, , damaged k-ix. attack killed 19 royal australian navy , 2 royal navy sailors, , wounded 10. explosion shook residences in area , damaged garden island s lights , telecommunications. other torpedo ran aground on eastern shore of garden island without exploding. m-24 dived , moved leave harbour.

the unexploded torpedo @ garden island several days after attack

a crossing on indicator loop recorded @ 01:58 believed midget submarine entering harbour, although later analysis showed reading indicated outbound vessel , therefore represented m-24 s exit. m-24 did not return mother submarine, , fate remained unknown until 2006.

ships ordered make open ocean. chicago left anchorage @ 02:14, leaving sailor behind on mooring buoy in haste depart. bombay, whyalla, canberra, , perkins began preparations depart.

just before 03:00, chicago leaving harbour, lookouts spotted submarine periscope passing alongside cruiser. @ 03:01, indicator loop registered inbound signal; m-21 re-entering sydney harbour after recovering attack 4 hours previously. hms kanimbla fired on m-21 in neutral bay @ 03:50, , @ 05:00, 3 auxiliary patrol boats—hmas steady hour, sea mist, , yarroma—spotted submarine s conning tower in taylors bay. patrol boats had set depth charge fuses 15 m (49 ft), , when sea mist passed on submarine had submerged , dropped depth charge, had 5 seconds clear area. blast damaged m-21, inverted , rose surface before sinking again. sea mist dropped second depth charge, damaged 1 of 2 engines in process , prevented making further attacks. steady hour , yarroma continued attack, dropping seventeen depth charges on believed visual sightings , instrument contacts of midget on next 3 , half hours. @ point during night, crew of m-21 killed themselves.

at 04:40, hmas canberra recorded japanese may have fired torpedoes @ her. may have been 1 of many false alarms throughout night. however, m-21 had attempted fire 2 torpedoes, failed because of damage bow either hmas yandra s ramming or depth charges, or possible collision uss chicago, making possible m-21 attempted attack cruiser. observer aboard canberra may have seen bubbles compressed air released fire torpedoes.

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