Truk Lagoon or Chuuk Lagoon

Rising up from the steep blue oceanic depths of the western Pacific Ocean, Chuuk State is one of the Federated States of Micronesia (FSM), an independent sovereign sovereign island nation formed in 1979 that consists of the four states of Yap State, Chuuk State, Pohnpei State and Kosrae State. Together the four states comprise some 607 islands scattered over some 1,700 miles just north of the equator to the north east of New Guinea.
Truk Lagoon, or rather Chuuk Lagoon as it has been known since 1990 (or confusingly simply ‘Truk’), is a natural harbour ringed by a protective reef some 140 miles in circumference and 40 to 50 miles in diameter. It is one of the many lagoons and atolls that make up Chuuk State.Chuuk State is the most populous state of the FSM with 50,000 inhabitants on 120 square kilometres (46 square miles). Chuuk Lagoon is where most people live. Weno Island in the Lagoon functions as state capital and is FSM’s biggest city.

Imperial Japanese Navy's Fourth Fleet Base

At the start of WWII in 1939, Truk Lagoon became the the base for the Imperial Japanese Navy Fourth Fleet, becoming the base for the Combined Fleet between 1942 and 1944. It acted as Japan’s main forward navel base in the Pacific.

In the early part of the war and as victories came easily to the Japanese onslaught, Truk served as the forward anchorage for the Japanese Imperial Fleet. When the Japanese Imperial Army arrived in numbers in January 1944, Truk was considered poorly equipped to defend itself. To defend against any amphibious invasion, the army established numerous coastal defence and anti-aircraft positions.

A U.S. Navy aerial reconnaissance photograph of Truk taken by a plane from the aircraft carrier USS Enterprise.
When heavily fortified, Truk Lagoon served as a safe haven. A sheltered and well protected forward base for the IJN main battle fleet. Super battleships such as the Yamato and the Musashi, together with vital aircraft carriers, cruisers, destroyers, tankers, tugs, gunboats, minesweepers, landing craft and submarines all thronged it’s waters.
The submarine tender Heian Maru and auxiliary oiler Teiyō Maru (left to right) at Paramushir in 1943.

Operation Hailstone

Once American forces captured the Marshall Islands in 1943, they could use them as a base to assault Truk Lagoon. When the first reconnaissance flight took place on 4th February 1944, large elements of the IJN fleet lay below all at anchor. The aviators’ eyes were astonished with the size of the fleet. Two subsequent reconnaissance planes were fired on by the Japanese, but managed to escape the Japanese fighters with priceless reconnaissance photos.

The IJN warships immediately left the lagoon to Palau, Singapore and Japan. Many of the smaller warships, destroyers and other vessels, including navel auxiliaries stayed behind. The auxiliaries could not depart so quick as they were offloading or still had supplies of tanks, mines, artillery, land vehicles, aircraft parts, aviation fuel and ammunition.

A US navel assault force, known as Task Force 58 was put together on 16th February 1944 consisting of battleships, cruisers, nine aircraft carriers and 500 combat aircraft.
The following day on 17th February 1944, Operation Hailstone began. Designed to destroy Japanese air power, Grumman F6F Hellcat fighters made sweeps of the lagoon at dawn. With uncanny parallels to the attack on Pearl Harbour, the Hellcat sweep was so swift and unexpected, the Japanese aircraft were caught by surprise and caught on the ground. Others scrambled, but with insufficient time they were shot down as they lifted off. Today, Japanese aircraft lay all around the lagoon, some in shallower water just metres from the airstrips.
Escorted by Hellcat fighters and throughout 17th and 18th February, US carriers now launched wave after wave of Douglas Dauntless dive-bombers, Curtiss Helldiver diver-bombers and Grumman Avenger torpedo-bombers to attack the now vulnerable Japanese shipping and land fortifications. In a one sided battle, more than 50 ships were sent to the bottom of the lagoon over these two days of Operation Hailstone.
A sinking Japanese merchant ship at Truk Lagoon, as seen from a plane from the aircraft carrier USS Enterprise

Toxic Aftermath

After the war, the sunken Japanese ships were left to rust at the bottom of the lagoon. The world moved on and the sunken ships of Truk Lagoon were forgotten about by the outside world.

The local Trukese islanders could not forget the ships however, as they had to deal with the toxic legacy of war. Many of these ships held large cargos of oil and aviation fuel, which continued to leak from the submerged hulks in significant quantities into the 1980s. Although the the leakage tailed off, smaller amounts of oil and fuel continued to leak to the surface into the 1990s and continued to burn locals and divers.
Today the leakage has largely diminished, but there can be still be a noticeable smell of fuel above some of the wrecks on occasion as a rotted 55 gallon fuel drum finally releases it’s contents.
Toxic fuel drums found on the Fujikawa Maru in 2016, where the surface still smelt of oil and aviation fuel.

Lagoon Of Lost Ships

In 1969 the legendary French oceanographer Jacques Cousteau and his team mounted and expedition to Truck Lagoon. They were to film an episode of the now famous Undersea World series. Many of the ship’s locations and identities were unknown at this time, but armed with old charts and local Trukese knowledge, the team began to locate and identify some of the wrecks. The resulting mesmeric and haunting ‘Lagoon of Lost Ships’ documentary was a hit around the world.
Play Video about Lagoon-Of-Lost-Ships-Jacques-Cousteau
While Cousteau himself only came for a few days, his crew stayed for two months, eventually leaving with tonnes of ‘relics’ salvaged from the previously undisturbed wrecks. Those relics, believed to still be in the Cousteau family somewhere, have never been seen since.
he wrecks, still holding their valuable war cargoes lay in a very remote location and were never deemed worthy of commercial salvage. They were left on the bottom of the lagoon, slowly rusted and untouched by man. Nature took control, covering the wrecks in an explosion of marine life with a myriad of corals and sea creatures. The wrecks became artificial reefs.

The First Dive Shop

Divers started to visit the lagoon in increasing numbers and in 1976, the National Geographic carried a 40 page feature on Truk by Al Giddings. A local Trukese, Kimiou Aisek who had been a young man on the islands when the US attack took place, opened the first dive shop in Truk Lagoon in the 1970s and went on to discover a large amount of the lost ships. Kimiou became a deeply revered and pre-eminent figure in the Truk Lagoon diving world for many years and the dive shop he opened in 1973 has gone on to become the beautifully appointed 54 room Blue Lagoon Dive Resort, set right on the lagoon and running 12 dive boats.

Since these days, Truk Lagoon has gone on to become the most celebrated diving location in the world. But even today and despite the countless millions of dives made in the lagoon, several of the ships known to have been sunk in the lagoon still remain undiscovered. Other vessels, known to have been present in Truk at the time of the attack have submerged outside of the lagoon and too deep for conventional scuba divers. Their exploration will be left to the divers and underwater explorers of the future. 

Ship Identifiers, Silhouettes, Location and Description​

Scuba Diving In Truk Lagoon Today

Scuba diving at Chuuk Lagoon today holds something for everyone. Far removed from the deep wrecks suitable only to today’s technical divers, there are shipwrecks and aircraft wrecks that you only need a snorkel to explore. There are many wrecks in shallow depths which are teeming with sea life and ideal for novice divers to explore.
The deeper wrecks on the other hand are so big that even after an exploration dive, the shallowest parts rise up to such a depth that most decompression penalties incurred on the deeper part of the dive are burnt off while exploring the shallower parts of the wreck as you ascend. As you would expect from a world class dive site, the dive facilities at the Blue Lagoon Dive Resort and the Truk Stop Dive Centre (both on Weno island) are first class, with all the comforts needed to make a trip to this remote part of the world more enjoyable.
Diver Dave blowing bubbles on the Betty Bomber.

Getting There

Most European travellers will take an international flight to any Asian hub that can get you to Guam. From there, the simplest flights are with United Airlines. Flights into Guam include United Airlines from Hong Kong, Manila and Tokyo-Narita. In addition, Japan Airlines flies from Tokyo-Narita, Koren Air from Seoul, and Philippine Airlines from Manila.

Dive Operators - Resorts

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Dive Operators - Liveaboard

This section is outdated. More details coming soon…..

Diving The Nippo Maru

The wreck today lays upright in 45 to 50 meters of water with a pronounced list to port. The least depth of the wreck is 24 metres to the top of the bridge superstructure, which is where the surface buoy is attached. The Nippo Maru is not the largest wrecks in the lagoon, but her size and the pleasant depths to her superstructure and decks mean that it is possible to go down to the deeper sections first and explore the whole of the wreck before returning to shallower parts.
Gas mask artefact on the Nippo Maru

Her five holds are packed full with ammunition and armaments of all kinds. Hemispherical mines, cannon barrels, gun mounts for shore batteries, machine guns, gas masks, bronze rangefinders and small arms ammunition of all kinds lie scattered all around this wreck. The bridge is almost intact with its ships compass and engine telegraph.

Engine Room Penetration Of The Shinkoku Maru

On 17th February 1944 and while anchored northwest of Fefan Island, Shinkoku Maru was hit amidships by a bomb dropped by a Douglas SBD “Dauntless” dive-bomber from USS Yorktown. Grumman TBF “Avengers” from USS Bunker Hill dropped six torpedoes on her, but all their torpedoes miss.

In the early hours of 18th February, TBFs from USS Enterprise dropped a near-miss bomb on the starboard side near the engine room that opens the hull. This hole sinks Shinkoku Maru with 86 men killed, including 16 of the crew.
Today, she comes to rest upright in relatively shallow water and sits upright on her keel in 40 metres of water with at least 10 metres to the top of her bridge structure. She is a massive ship and the second largest in the Lagoon. Given her depth, a long dive starting at her deepest parts around the engine room at her stern and ending at the shallower bridge, a dive can be carried out with the minimum decompression.


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