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Dive Truk Lagoon

   Appeared in DIVER August 2014 (by Rod MacDonald)

Ask wreck-divers where in the world they would most like to be, and the answer ’Truk’ would come as little surprise. Wreck expert ROD MACDONALD has taken time out from Scottish wrecks to write a guide to the iconic diving destination in Micronesia

WHEN MY GOOD FRIEND and regular dive buddy Paul Haynes and I were asked to present at the OZTeK 2013 conference in Australia, we decided that after the event we would return home to Scotland via Truk Lagoon. I had been there several times but Paul had not, although he had had to suffer hearing about it from me for years. I also asked another good friend, Ewan Rowell, who did most of the underwater photography for my early books, if he’d like to come to OZTeK and then on to Truk with us. So, after a whale of a time in Sydney, the three of us visited Truk in March last year. I hadn’t decided to write a book about Truk wreck-diving at that stage, but once there it became clear that although Truk is one of the world’s great wreck-diving locations, there was almost a complete lack of hard diver information, other than a few good but older books.

Although there are lots of good close-up photographs of specific artefacts inside the wrecks, there seemed to be no decent illustrations of what the wrecks actually looked like on a larger scale. I suspected that if you asked most divers what the ship they had been diving actually looked like, many would not know. So, on the long flight home, I decided to write the book and make my contribution to Truk wreck-diving. I determined to illustrate the main wrecks divers tend to visit on a one- or two-week diving holiday.

Chuuk Lagoon, as Truk Lagoon has been officially known since 1990, is a great natural harbour 40-50 miles in diameter, ringed by a protective reef about 140 miles in circumference. Rising from the deep blue oceanic depths of the western Pacific, the many lagoons and atolls of Chuuk State form one of the four Federated States of Micronesia – Yap, Chuuk, Pohnpei and Kosrae – that together comprise 607 islands scattered over almost 1700 miles north-east of New Guinea.

By the start of World War Two, Truk Lagoon had become the Imperial Japanese Navy’s Fourth Fleet Base, and from 1942-1944 it was the Japanese Combined Fleet’s main forward naval base in the Pacific. A significant portion of the Japanese Fleet was based there, and it was a focal point for supplying and resourcing the conquered Japanese Greater Asia Prosperity Sphere islands and territories.

TRUK HAD BEEN FORTIFIED against an anticipated amphibious invasion with coastal defence and AA gun positions, a military infrastructure of roads, trenches, bunkers, caves, five airstrips, seaplane bases, a torpedo-boat station, submarine repair centres, a communications centre and a radar station.

The Japanese garrison comprised almost 28,000 Imperial Japanese Navy personnel and almost 17,000 Imperial Japanese Army service personnel. US forces had captured the nearby Marshall Islands in 1943, but even at this stage of the war the Allies had no real idea of the scale of what lay in the lagoon – it had been off-limits to foreigners for decades, and shrouded in great secrecy. When the first long-range reconnaissance overflight by US Navy Liberator aircraft took place on 4 February, 1944, the sight that met the aviators’ eyes was astonishing.

Large elements of the Japanese Imperial Navy Fleet lay below – battleships, cruisers, submarines and aircraft-carriers were at anchor, along with a huge number of vulnerable naval auxiliaries, merchant supply ships and tenders. US military planners immediately made plans for a carrier raid but, knowing that the secret of their presence was out, the valuable heavy Imperial Japanese Navy warships immediately left the lagoon. However, many smaller warships, destroyers and light cruisers stayed behind as heavily laden naval auxiliaries frantically tried to off-load cargos of tanks, beach mines, land artillery, shells, vehicles, aircraft, spares and masses of small arms ammunition before they too could leave.

TASK FORCE 58, a US naval assault force of battleships, cruisers and nine aircraft-carriers carrying 500 combat aircraft, was immediately assembled and approached the lagoon undetected to take up a holding position about 90 miles off Truk on 16 February, 1944. The next day, Operation Hailstone began at dawn with Grumman F6F Hellcat fighter sweeps of the lagoon designed to destroy Japanese air power.

The Hellcat sweep was so swift and unexpected that, with uncanny parallels with the Japanese attack on Pearl Harbor, many of the Japanese aircraft were caught by surprise and destroyed on the ground, while others were shot down as they scrambled to get airborne. Those that did get airborne were shot out of the sky, and today Japanese aircraft lie around the lagoon, some in shallow water just hundreds of metres from the end of their airstrips.With US air superiority established, carriers launched wave after wave of dive-bombers and torpedo-bombers escorted by Hellcats, to attack the now-vulnerable shipping and land fortifications. They met limited anti-aircraft fire from the lightly armed merchant ships and the island land defences. It was a one-sided battle – and more then 50 ships were sent to the bottom of the lagoon.
In 1969, French oceanographer Jacques Cousteau and his team mounted an expedition to Truk Lagoon. The resulting mesmeric and haunting television documentary Lagoon of Lost Ships was an instant hit around the world.
Our “welcome to Truk” dive was straight into the engine-room of the Shinkoku Maru before exiting to explore the rest of this massive tanker in a two-hour dive. This was followed by a second two-hour dive in the afternoon, and this became our normal pattern. Our closed-circuit rebreathers were perfect for Truk, giving long run-times with little deco. Lying in the sheltered waters of the lagoon, the wrecks are structurally in very good condition, barring their war wounds, and are still packed with their wartime cargoes.

One of our stand-out dives was the 384ft, 5831grt [gross register tonnage] San Francisco Maru, originally built as a passenger-cargo vessel in 1919. After 20 years of civilian service, she was requisitioned as a naval transport at the outbreak of war in the Pacific, in December 1941. She left Japan in a supply convoy for Truk, arriving there on 5 February, 1944, and anchoring in the Fourth Fleet Anchorage, south-east of Dublon Island. During the US air strikes of 17/18 February, several aircraft attacked her and she was hit by a number of 500lb bombs and set on fire amidships. With catastrophic damage to her shell-plating and hull, water flooded into her two aft holds and she was dragged under by the stern. Today the wreck of the San Francisco Maru rests upright in about 60m with a least depth to its bridge superstructure of about 45m, its main deck at about 50m. It is still filled with its wartime cargo – some of which is particularly photogenic, such as the deck cargo of tanks. Aft of a large gun at the bow, the 8ft-high tween-decks space of hold no 1 is packed with hundreds of hemispherical beach mines, ready for burial on beaches that the Allies would possibly assault.

IN THE TWEEN-DECKS of hold no 2, two tanker trucks and a staff car can be found, while on the deck level below 50lb aerial bombs stand alongside artillery shells and a radial aircraft engine. The foremast with its H-frame support and cross-tree is still upright on deck between hatch 1 and 2. On the main deck in front of the bridge superstructure on the starboard side are two three-man Type 95 HA-GO light Japanese battle tanks. On the port side sits another Type 95 resting partly on the gunwale – its barrel pointing forward and slightly depressed. A large steamroller can be seen lying on the seabed nearby on the port side. In the aft holds are lorries, artillery shells in boxes, more hemispherical beach mines, detonators, bombs, small arms ammunition and 55gal fuel drums.  Hold no 5 contains dozens of 30ft Long Lance torpedo bodies and engines plus a lot more of the fuel drums.

Another iconic Truk wreck dive is the 9627grt Rio de Janeiro Maru, a substantial eight-deck passenger-cargo liner built by Mitsubishi in Nagasaki in 1929 for the Japan to South America run.  She was 461ft long with a beam of 62ft and could accommodate 1140 passengers. Large cargo holds were set fore and aft of the long central superstructure. The Imperial Japanese Navy requisitioned her on 8 October, 1940, and work began to convert her to a naval auxiliary transport. She was latterly converted to a submarine tender and attached to the Combined Fleet.
On 3 February, 1944, she set off from Yokosuka for Truk, escorted by the Mutsuki-class destroyer Yuzuki, arriving on 11 February – just six days before Operation Hailstone. She was struck by several 1000lb bombs from US aircraft in the first group strikes of the day after the Hellcat fighter sweep. They caused severe damage and started fires aboard. She started to sink, slowly listing to starboard before finally slipping beneath the waves 30 minutes after midnight the next day. By daylight on 18 February, US aircraft found no sign of her.
Today the wreck of the Rio de Janeiro Maru is one of the most popular in the lagoon. It lies 400-500m offshore from Uman Island on its starboard side, in relatively shallow water. With that broad beam, the wreck’s shallowest parts rise to within 10-15m of the surface. This is a massive ship, one of the largest in the lagoon, and lying in such shallow water allows divers long bottom times with little deco penalty. This beautiful ship is so intact that it looks as if it would float, even more than 70 years later. Several feet aft of the bow, its name in large Roman and Kanji non-ferrous letters can be made out, interspersed with portholes with glass intact. On the now-vertical forecastle deck sits the 5.9in bow gun; the foremast still jutting out horizontally from a masthouse between holds 1 and 2. Hold 2 contains a 15ft-diameter circular base support for a large artillery piece destined for installation on the land, along with recoil springs and a number of large-bore artillery barrels. Rows of portholes line the lower levels of the long superstructure, while on the two deck levels above, long promenade walkways run along either side of the superstructure with cabins leading off – now entered through vertical doorways.

IN THE ENGINE-ROOM, where the walls are covered with switching panels, gauges and two telegraph repeaters, divers can find the Mitsubishi Sulzer diesel engines. The funnel is still in place, bearing its shipping-line markings, along with its steam whistle, running lights and fixed ladder. Several sets of lifeboat davits are located along the uppermost port side of the superstructure on the boat deck. Hold 4 contains coal and another large circular artillery base, runners for the ball-race and a large artillery barrel. Hold 5 contains masses of bottles, many of which are still stacked in their original wooden crates. Moving around the stern, the ship’s name is again easily legible. The Rio was a twin-screw vessel and both screws are still present, flanking the large rudder. The uppermost four-bladed port propeller dominates the area and dwarfs any diver.

In 2013 a katana sword, which may have been hundreds of years old, was present on the wreck. These were highly treasured weapons, and often passed from one generation to the next.

This is just a snapshot of Truk – there are more than 30 large wrecks and a number of complete aircraft wrecks for divers to explore.

Dive Truk Lagoon: The Japanese WWII Pacific Shipwrecks by Rod MacDonald
is released on 31 July by Whittles Publishing, www.whittlespublishing.com
ISBN 9781849951319, 288pp, £30

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