Bikini Atoll · Marshall Islands · Wreck · Artificial reef
USS Arkansas
A 1911 battleship, inverted at 55 m by an atomic shock wave
Photo: exit78 · Public domain
USS Arkansas was moored 230 m from the Baker underwater detonation, close enough that the shock crushed the starboard side of her hull and rolled the battleship over onto her port side. She lies inverted in about 55 m of water on the floor of Bikini lagoon, where the ship now works as an artificial reef, and she is a staged-decompression dive from the moment you leave the surface.
Also known as USS Arkansas (BB-33), BB-33.
Where it is and how deep
No published position for this site — the map shows Bikini Atoll and its other sites; operators know the mooring.
The dive
Arkansas lies inverted in about 55 m of water at the bottom of the lagoon, which puts the whole ship below recreational depth and makes the descent the least interesting part of the dive. The upturned hull is what you meet first and it is continuous over roughly 171 m, with the deck, the superstructure and the armament underneath it where the ship rolled onto them. Nothing is where a plan would put it.
Bottom time is the constraint rather than the wreck. Charters run Bikini as a technical destination with a deco-bar for the staged stops, so a single visit covers one part of the hull and the rest waits for another dive. The lagoon holds 27 to 29 °C all year with visibility over 30 m, and the ship has been down since 1946: it now acts as an artificial reef, and National Park Service divers surveyed and documented it in 1989 and 1990.
The wreck
- Vessel
- USS Arkansas
- Type
- Battleship
- Length
- 171 m (561 ft)
- Built
- 1911
- Sunk
- 1946
- Cause
- Hull crushed and the ship rolled over by the Baker underwater nuclear blast 230 m away
- Lies
- Inverted in about 55 m on the floor of Bikini lagoon, acting as an artificial reef
Arkansas was launched on 14 January 1911 and commissioned on 17 September 1912, and by 1946 she was expendable enough to be anchored 230 m from the Baker aim point. The shock of the underwater shot was transmitted directly to the hulls of the target fleet, and Arkansas, the closest ship in the target fleet to the bomb, appeared to have been crushed as if by a tremendous hammer blow from below; the wave rolled her onto her port side and she sank on 25 July 1946. National Park Service divers returned to survey and document the wreck in 1989 and 1990.
Marine life and season
The sources we used don't single out particular species here.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Fair | Fair | Fair | Good | Good | Good | Good | Good | Good | Good | Good | Fair |
Season follows Bikini Atoll: Charters run in the calmer Apr-Nov window; remote crossing logistics and permit scheduling limit trips outside this period. Residual radiation is monitored and considered low for dive visits.
Dive videos
USS Arkansas (BB-33) at Bikini Atoll · FinnborgBraga on YouTube
Diving the USS Arkansas 070524 · Didier Follain-Grisell on YouTube
Questions divers ask
How deep is the USS Arkansas wreck?+
The ship lies inverted in about 55 m of water on the floor of Bikini lagoon. That places the entire wreck outside recreational limits, so it is dived as a technical, staged-decompression profile with a deco-bar on the ascent.
Why does USS Arkansas lie upside down?+
She was only 230 m from the Baker underwater detonation on 25 July 1946. The shock wave crushed the starboard side of her hull and rolled the battleship over onto her port side, and she went to the bottom of the lagoon inverted.
Sources
- USS Arkansas (BB-33) — Wikipedia
- Operation Crossroads — Wikipedia
- Bikini Atoll — Wikipedia
Photo credits
- Sunken hull of the capsized USS Arkansas battleship seen underwater at Bikini Atoll by exit78, Public domain, via Openverse
- Line diagram of the capsized USS Arkansas hull sketched by NPS divers by National Park Service, Jerry Livingston and Larry Nordby, Public domain, via Wikimedia Commons
In The Logbook
- Why is 1.4 bar the oxygen limit in diving?Body & health · 13 min read
- Air, nitrox or trimix: which gas, and when?Gear & kit · 15 min read
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