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The Other Wrecks of Chuuk Lagoon

Aikoku Maru

Known as "Half a Wreck" the Aikoku Maru is one of the most damaged ships in the lagoon, with only the stern half remaining. Initially built as an ocean liner the Aikoku Maru never saw service in this role; having been taken over by the Japanese navy straight from the shipyard. With her sister ships, Hokoku Maru and Gokoku Mary, she was intended for use on the Japan-Africa liner service. All three liners were the best vessels Japan had made to date. With 48 First Class, 48 'Special' Third Class and 304 'Regular' Third Class cabins, these vessels could reach a top speed of 20knots, a cruising speed of 17knots and could easily out run most merchant ships of the time.


There are two likely scenarios that describe how the Aikoku Maru met her violent end.  Whilst both involve an unidentified U.S. plane, the sequence of events surrounding the plane differ.  The sheer deviation caused by the explosion make it impossible to determine the actual cause of the damage. One account has an Avenger being disintegrated in mid air by the shockwave of an explosion.  The second has the Avenger, hit by anti-aircraft fire from Dublon, spiralling out of control into the bridge of the Aikoku Maru.  The wreckage of the plane fell into the forward hold and sometime later the Aikoku Maru violently exploded. So what was in the forward hold that would cause such an explosion? The magazines for the gun, mines, ammunitions, bombs and other high explosives were carried in these holds. The force of the explosion caused a shallow depression in the sea bed in which the structure now lies; no pieces of the fore ship have been found.

The wreck lies east of Dublon Island in about 70m of water, with the top of the bridge at 40m and the deck at 49m. We dove the Aikoku at 8:18am, Saturday 29th September 2001, as the fourth last dive of our 1st trip. Maximum depth was 53.4m when I did a brief and shallow entry into the stern hold to see if it contained anything. However, due to the overcast day I couldn't see the bottom of the hold. Total dive time 44 mins.

The most obvious features we noted in the short time we had on this wreck were;

  • The extensive damage to the bow section; it really is difficult to describe amount of damage, or, to image the force of the explosion, but it is a mangled assortment of steel - all twisted and bent.

  • Swimming towards the stern we passed anti-aircraft guns positioned on each side of the top deck. The guns are frozen pointing to the sky as if still shooting passing planes.

  • There are two hold aft, but we could not see if they had anything in them because of the poor light and depth within them.

  • A huge stern gun points over the port side, elevated upwards as if it to was firing at something.  This is a big gun that comes into view as you swim over the aft holds.

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Amagisan Maru

The Amagisan Maru was a large freighter launched on 6 November 1933 by Mitsui Bussan Kaisha Ltd of Tama, Japan. The ship was 7,620 tons gross, 137 metres (454.0 feet) long and 18.3 metres (60.0 feet) wide. The Amagisan Maru was used on the New York to Japan route but on 28 September 1941 the ship was placed in the service of the Japanese Navy as a special transport.

On 14 February 1942 she was attacked by the submarine USS Swordfish and suffered medium damage. Two years and three days later the Amagisan Maru was anchored off the south-western corner of Uman Island in Chuuk Lagoon when the first planes of Operation Hailstone flew into the vast lagoon. The Amagisan Maru was the largest of the ships anchored on this side of the island and the planes from USS Bunker Hill CV17 targeted her for death. Five Curtis Helldivers single engine dive bombers and Four Grumman Avenger single engine torpedo bombers, attacked the Amagisan Maru during Strike 3D at about 1250 hours. One 1,000lb bomb from a Helldiver hit the Amagisan followed by a torpedo from an Avenger just forward of midships. This ignited a fuel oil fire that burned fiercely, within 15 minutes she was sinking by the bow. By the next attack run, she had sunk.

The picture below shows the torpedo strike; notice the three splashes where the torpedo dolphined (jumped out of the water) before running straight at the ship. There is a 2nd torpedo trail that appears to have missed.

There are three other ships in this picture; the Yubai Maru is top left (it sunk there), the other two are unknown. The Sankisan Maru is possibly obscured by the white water plume.

Today the Amagisan Maru lies on a gentle slope with the bow in less than 30 metres and the stern in 58 metres. The wreck has a 45 to 50° list to the port and faces back towards the southern end of Uman Island. This is an interesting wreck, it's only a pity it is in such deep water. There was a fuel tanker truck on the deck when the ship went down. It has slid off the deck and lies on the sand next to the forward hold. The forward masts has fallen over and hit the cabin of the tanker, crushing it. There is a large bow gun still intact, and the anchor can be see lying out on the sand with the chain running all the way back into the ship. The forward number 1 hold is mainly empty except for a few empty fuel drums. Hold number 2 contains some aircraft wings and more barrels. At the rear of the hold is a car with its cab mostly intact.

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Dai Ni Hino Maru

The Dai Ni lies on a fairly steep incline with the now famous bow gun in less than 3m, while the stern is a lot deeper at 20m. Apart from the bow gun there is a lot to see on this wreck albeit spread out and difficult to find. However the searching is half the fun and the shallow depth gives good long bottom times. In fact on our first visit we didn't even get to the "deep end" as we spent all our time searching the bow section. There is some great fish life on and around the wreck.

The Dai Ni suffered huge damage during the attack; only the bow and the gun remain distinguishable, the rest of the vessel is completely destroyed. There is no deck, holds, bridge...or anything else...just the sides of the vessel and complete destruction within. The doesn't have much growth, however it is interesting to note that Lindemann says there was no growth on the barrel. However there is now a large coral growth on the end of the barrel - this has clearly grown in the last 20 years. A small section of the anchor chain is still intact and hangs from the hawse hole, while the anchor lies on the sand a little way in front of the wreck.

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Fujikawa Maru

The Fujikawa Maru was built as a passenger-cargo ship by Mitsubishi Heavy Industry at Nagasaki. It was launched on 15 April 1938 for Toyo Kaiun. Displacing 6,938 tons, it was 132.6 metres long and 17.8 metres wide. Originally used on the Japan/North American run and then chartered to Mitsui Busan for use to South America and India. On 9 December 1940 it was taken over by the Imperial Japanese Navy, converted to an aircraft ferry and was fitted with 6" bow and stern guns. She was used all over the Pacific as an armed aircraft transport or ferry, and delivered planes and aircraft parts to island parts through the Indo-China region.

On 12 September 1943 on a trip from Kwajalein to Chuuk, the Fujikawa Maru was torpedoed by the submarine USS Permit. Despite extensive damage, she arrived in Chuuk three days later. By January 1944 the vessel had been repaired in Japan and these repairs can be seen today on the port side waterline near the funnel. On 17 February 1944, planes from USS Bunker Hill CV17 and Monterey attacked the Fujikawa Maru and in strike 3E-1 two torpedos were dropped and at about 1420, one hit just rear of the funnel. The ship did not sink immediately (it is reported that it did not sink until the next morning) and there is a report that it was hit by a 1000 lb bomb on the port quarter but this is not confirmed

Today the wreck lies sitting on even keel in water 34m to the bottom and is probably one of the most dived wrecks in Chuuk, because of the relatively shallow depth and the abundance of artefacts and structures to see. One of the most striking features in the impressive bow gun, which is slightly raised and pointing a little to starboard. However, the most interesting things are to be found in hold number 2; aircraft fuselage pieces, cockpits and wings and other assorted Zero fighter bits. There are also torpedoes, propellers, cables, papers, plates and assorted debris scattered all around. It is also possible to penetrate the bridge area and into the main superstructure where there is a bathroom with a large communal tiled bath. The ascent and safety stops are a pleasant experience too, with multitudes of fish and coral to look at on the mast.

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