The Iron Bottom Sound

Only For Wreck Lovers: Dive Into Something Different!

Iron Bottom Sound is a stretch of water between Guadalcanal, Savo Island, and Florida Island in the Solomons. Originally called Savo Sound, it was renamed by the Allied Forces in recognition of the dozens of ships and planes that sank there during the Guadalcanal Campaign.

Battles of WWII

You can broadly break World War II in the Pacific in 3 major stages:

  • The Awakening of The Beast with the Pearl Harbour Attack
  • The Pacific Retake by the Allies
  • The American Victory with the Atomic Bomb.

For us, divers and wreck lovers, the second stage is the most interesting.

Each battle in the Pacific created a vast wreck graveyard. Most people know of the famous places like Peleliu in Palau and, of course, Truk Lagoon; but divers often overlook the Solomons. The Guadalcanal Campaign happened in the Solomons and the result is Iron Bottom Sound.

For the armies and, especially, the navy, this area carries memories they will not forget. As an example, every year on the battle’s anniversary a US ship cruises into The Sound and drops a wreath, to commemorate the men who lost their lives. For many Navy sailors, and those who served in the area during that time, the Sound is also considered sacred, and strict silence is observed as ships cruise through.

The Iron Bottom Sound in 1942 with Savo Island (center) and Guadalcanal (left) – source: U.S. Navy, photo taken from USS San Juan (CL-54)

Differences between the wrecks

The military operation in Truk Lagoon – Operation Hailstone – only lasted 2 days, while the one in the Solomons – the Guadalcanal Campaign – lasted a vast 6 months. The difference in state of the shipwrecks in both locations is therefore clearly visible. In the Solomons, most of the ships went down while they were in active fighting. This is very different from the Truk Lagoon wrecks.

The wrecks in Truk Lagoon are relatively pristine as they were sitting still during the bombings. In the Solomons, you will see clearly the battle wounds and war damage on the wrecks. This is what makes Solomon wrecks so interesting to dive and explore.

Shaz Kozak, Solomons Master Operations Manager.

The other major difference is the type of ships you will find. In Truk Lagoon, all of the wrecks are Japanese; Iron Sound Bottom does not discriminate. You will be able to dive US, NZ and Japanese wrecks. A reminder that a world war affects all nations.

Nowadays in Iron Bottom Sound

There are at least 50 diveable wrecks in Iron Bottom Sound. Most of them are within recreational limits but many lay at the edge of those depths and well beyond. The map below gives you the approximate locations of all the major wrecks. We still think there is plenty more to discover but we are sure you get the idea that there is LOTS to see.

Iron Bottom Sound wrecks
Map of the location of World War II shipwrecks in Iron Bottom Sound in the Solomon Islands. Some wreck positions are not exactly known. Credit: V. Wolny

Most of the time we will do two or more dives on a single wreck. This way you will have time to properly explore and enjoy the wrecks. Some of these vessels are also extremely large so the more dives you do the better!

You can broadly separate the Iron Bottom Sound into 4 areas that almost also correspond to the dates they sank.

  • Florida Island
  • Guadalcanal Island
  • Savo Island
  • Anything in the middle

Florida Island

Remains of a landing craft at Ghavutu Harbour
Remains of a landing craft at Ghavutu Harbour – credit: Heather Sutton

Most of the wrecks (not all) at Florida Island sank during Operation I-Go which took place from 1st until 16th April 1943.

The highlights and must-see wrecks around the Florida are the RNZN Moa and USS Kanawha. We also often dive a half-wreck of the USS Minneapolis. Only the bow section remains as they managed to repair the vessel.

Another stunning site around Florida is Ghavutu which is a bit like diving at White Beach. Around this old wharf, you also will find over 13 Mavis planes and a lot of wreckage and artifacts.

Lastly for tech divers, the USS Aaron Ward waits upright in 63m to 75m of water.

Guadalcanal Island

The Naval Battle of Guadalcanal took place from 13th to 15th November 1942. It was an effort by the Imperial Japanese army to recapture Henderson Field. The Japanese navy organised a large naval party to bring troops onto Guadalcanal Island to re-capture the airfield. Both sides suffered heavy losses during this battle.

Nowadays, most of the wrecks you find along the northern shores of the island are linked to this battle. Many of them are Japanese vessels that the Imperial navy beached. Most of the US vessels were sunk far from shore, hence too deep for us to dive.

Kinugawa Maru ((Bonegi II) beached on Guadalcanal Island
The Kinugawa Maru ((Bonegi II) beached on Guadalcanal Island Northern shores – Credit: US Navy photo archives

One of the major group of sites not to miss are beaches we call simply Bonegi I, Bonegi II and Bonegi III. Three Japanese ships are located, one on each of the beaches.

Bonegi I with the wreck of Hirokawa Maru
Bonegi I with the wreck of Hirokawa Maru – credit: Gerald Rambert

Hirokawa Maru (Bonegi I) was a 156m (468ft) cargo vessel turned into a seaplane tender. It has now become an absolutely spectacular artificial reef. Kinugawa Maru (Bonegi II) was a cargo ship, and Kyusyu Maru (Bonegi III) was an attack transport vessel.

engine block of the Kinugawa Maru (Bonegi II) Solomons
The engine block of the Kinugawa Maru (Bonegi II) – photo credit: Adam Beard Photography

Savo Island

Savo Island is a round island sitting right in the middle of the sound. This island is infamous, seeing multiple battles during the campaign. Unfortunately, history remembers it by naming battles for it.

  • The Battle of Savo Island (First Battle of Savo Island) took place on 8th and 9th August 1942.
  • The Battle of Cape Esperance (Second Battle of Savo Island) on 11th and 12th October 1942.
  • The Third Battle of Savo Island was Guadalcanal Naval Battle (see above)
  • The last one was the Battle of Tassafaronga on 30th November 1942 (Fourth Battle of Savo Island)

It was that (in)famous that the US Navy named, in memoriam of the fallen, one of its escort carrier USS Savo Island in 1944.

Savo Island Solomons in the Iron Bottom Sound
Savo Island right in the middle of the Iron Bottom Sound – photo credit: Piensa & Geotermia

With so many battles, the island is surrounded by wrecks. Unfortunately for us, without a fancy submarine, most of the wrecks sank around Savo are unreachable.

Thanks to Paul Allen though, most of the wrecks around Savo have been identified and located. The mapping project of Iron Bottom Sound in 2015 positively identifed some of the Savo wrecks like the USS Vincennes at 1050m+ and the USS Astoria at 850m+. The project visited several of wrecks by submarine.

USS Astoria name on hull
Astoria name on hull – credit: Mapping Project Iron Bottom Sound

The middle of Iron Bottom Sound

A few wrecks can be found between Guadalcanal Island, Savo Island, and the Florida Islands, right in the middle. Most of these wrecks either sank due to damage or were purposely sank to avoid capture (heavily damaged of course). Most of them were re-discovered during a 1992 expedition led by Robert Ballard, including USS Monsen, USS George F. Elliott, and the USS Barton. But the most famous wreck he re-discovered is one for the technical divers. The USS Atlanta is a dive only for the very brave! Very few people actually have had the chance to dive it and we hope to be able to mount expeditions in the future.

technical diver exploring the shipwreck of USS Atlanta
GUE technical diver exploring the shipwreck of USS Atlanta (CL-51) – Credit: Return To The USS Atlanta: Defender of Guadalcanal (still from video – May 201)

Dive into something different with Master Liveaboards! Join us on Solomons Master on our WWII Wreck Week itinerary. As the name says, this itinerary will take you diving on some of the many WWII wrecks which are resting in the Iron Bottom Sound. You also have the chance to visit some land-based tours to visit the battlefields, Japanese caves, and several other magnificent WWII remnants.



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