Chuyo Maru (Palau — 120 fsw)


Chuyo Maru is one of the many shipwrecks in the lagoons around Koror that resulted from Operation Desecrate One.

A “maru” is a Japanese merchant ship. During the war, many merchant ships were converted for use in wartime and equipped with guns, depth charges, etc. in order to help defend themselves as they ferried cargo from Japan to these remote atolls.

Part of the US strategy in the Pacific in WW II was to move west across the different atolls and islands where Japan had established a foothold with airbases and operations. We didn’t want the enemy to attack us from the rear as we moved west to get close enough to send bombers to Japan.

After we conducted the infamous Operation Hailstone at Chuuk on 17-18 February 1944, the next target was Palau.

The Japanese knew it was coming since it was the next obvious location west of Chuuk; however, they didn’t expect to happen as quickly after Chuuk. Just a short 6 weeks later, we conducted Operation Desecrate One on 30-31 March 1944. During that battle, we sank or damaged thirty-six Japanese ships. The Japanese were able to get some of them out of the lagoons but we largely caught them by surprise.

The Wreck

The Chuyo Maru was built in 1942 and has an overall length of 295 feet and a beam of 40 feet. It had a coal burning steam engine that was located in the aft. The kingposts are readily identifiable and are forward of amidships. The superstructure is forward of the kingposts.

The Chuyo Maru was bombed multiple times with 500-lb bombs by TBF Avengers and then later by F6F Hellcats. Japanese dispatches reported that the ship sank at 8pm on April 1.

The Chuyo Maru was never prioritized for salvage even though the location was known. Therefore, the wreck is still largely intact. The wreck was rediscovered in 1989 by Francis Toribiong and Klaus Lindemann. It is a few hundred yards offshore of Ngargol Island.

Visibility can vary on this wreck depending upon conditions and whether the tide is incoming or outgoing. It can also vary from bow to stern. We had what I would consider pretty good visibility on the day we did the dive but it did start to deteriorate.

Given the depth of the wreck and the fact that I was only using a single AL80 tank, my bottom time was limited. Luckily, I was diving with the guide and divemaster Ogie who has an excellent understanding of the ship and showed me quite a few key points of interest. When I return later this year with my rEvo, I will have more time and can further explore the wreck but this was a great introduction.

I’ve included a graphic of the wreck from the Fish ‘N Fins website and one from the excellent book “Dive Palau The Shipwrecks” by Rod Macdonald. This will help orient the reader to the pictures. Some of the key features I explored and photographed were the large kingpost mast forward of amidships, the engine room,

Graphic from the Fish ‘N Fins Website
Graphic from Diving Palau The Shipwrecks


Below are photos of some of the key areas of the wreck.


Note the intricate bracing between the masts. The top of the kingpost is about 35 feet deep. Like most masts I saw on wrecks in Palau, they are home to a lot of sealife.

Engine Room

The engine room is one of the deeper areas of the wreck and I was running close to getting into decompression so I had a limited amount of time to explore but I did get a few minutes to look around at the quadruple-expansion steam engine. I’ve also included a pictures of the skylights which are typically one of the ways to enter the engine rooms on these wrecks (but we didn’t in this case). On this ship, there are two sets of skylights – one for engine room (three skylights) and one for the boiler room (two skylights).

Bow Locker Room & Anchor Machinery

Miscellaneous Pictures

Derrick boom from the port king-past
Foremast at the bow
Gun at the stern
Fallen smokestack

Next Dive

These are notes for me primarily for reference on my return. Some key things to look for include:

  • Telegraph & compass in the superstructure / bridge
  • Ammo boxes at the rear gun
  • Depth charge launchers with depth charges each side of the fantail
  • Coal wheelbarrows
  • Galley
  • Anchor & wide angle picture of the bow


Dive Palau The Shipwrecks by Rod Macdonald

The Wrecks of Palau by Dan Bailey

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