Chuuk Lagoon · Micronesia · Wreck
San Francisco Maru
Type 93 torpedoes still stowed in the holds
Photo: montereydiver · CC BY 2.0
A 117-metre navy transport bombed in the February 1944 raids and now upright with her deck cargo where it was carried: trucks and tanks are still on deck. The forward mast reaches up to 27 metres, but the stern lies at 64 and the seabed at 70, which puts this ship past recreational limits for almost all of its length.
Also known as Soko Maru.
Where it is and how deep
7.3623° N, 151.9010° EApproximate position — the dashed circle shows where the site lies; your operator's briefing has the mooring.
The dive
The mast tops at 27 metres are the shallowest thing here and everything else is below them, so the dive gets planned from the bottom up rather than the other way round. The hull sits upright, 117 metres long and 15.5 across, with the stern down at 64 metres and the sand at 70. The deck cargo is still aboard: trucks and tanks stand on deck where they were loaded.
Below decks she was carrying a munitions manifest - mines, torpedoes, bombs, artillery and aircraft engines - and Type 93 torpedoes are documented in her holds. Bottom time at 64 metres is short and the decompression obligation long, so a dive here covers a fraction of the ship rather than its length. Six 500-kilogram bombs from Essex and Yorktown aircraft put her here on 16-17 February 1944.
The wreck
- Vessel
- San Francisco Maru
- Type
- Navy transport and freighter
- Length
- 117 m (384 ft)
- Built
- 1919
- Sunk
- 1944
- Cause
- Hit by six 500 kg bombs from Essex and Yorktown carrier aircraft in Operation Hailstone
- Lies
- Upright, stern at about 64 m and the seabed at 70 m
San Francisco Maru, also carried as Soko Maru, was launched at the Kawasaki shipyard in Kobe on 1 March 1919 and commissioned a fortnight later on 14 March. As a 5,831-ton navy transport and freighter she was at Truk in February 1944 when carrier bombers from Essex and Yorktown attacked, and six 500-kilogram bomb hits sent her down stern-first. Jacques-Yves Cousteau located the wreck in 1969 and identified her from the ship's bell found on site.
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 |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Prime | Prime | Prime | Good | Good | Fair | Fair | Fair | Fair | Good | Good | Prime |
Season follows Chuuk Lagoon: December to April is the dry season, driest from January to March; June to September brings the heaviest rain.
Photos from San Francisco Maru
montereydiver · CC BY 2.0
montereydiver · CC BY 2.0
Apiquet · CC BY-SA 3.0
Dive videos
Diving the wreck of SAN FRANCISCO MARU - Truk Lagoon · Rod Macdonald on YouTube
WWII Tanks at 210ft | The Million Dollar Wreck – San Francisco Maru · Señor Scuba on YouTube
Questions divers ask
Is the San Francisco Maru a technical dive?+
Yes. The forward mast starts at 27 metres, the stern lies at about 64 and the wreck rests on a 70-metre seabed, so bottom time is short and the decompression obligation is significant. Mixed gas and technical certification are expected before an operator will run the dive.
Sources
- San Francisco Maru — Wikipedia (German)
- Operation Hailstone — Wikipedia
- Chuuk — Wikivoyage
- Type 93 torpedo — Wikipedia
- San Francisco Maru — ScubaGo
Photo credits
- A Type 95 tank standing on the deck of the San Francisco Maru wreck by montereydiver, CC BY 2.0, via Wikimedia Commons
- Close-up of a coral-covered Type 95 tank on the San Francisco Maru by montereydiver, CC BY 2.0, via Wikimedia Commons
- Looking up at mines stacked inside the San Francisco Maru's hold by montereydiver, CC BY 2.0, via Wikimedia Commons
- A naval mine and artillery shells inside the San Francisco Maru by Apiquet, CC BY-SA 3.0, via Wikimedia Commons
In The Logbook
- What is decompression sickness (the bends)?Body & health · 18 min read
- How a rebreather works, and what it buys youGear & kit · 8 min read
- Why is 1.4 bar the oxygen limit in diving?Body & health · 13 min read
- How long to wait before flying after divingBody & health · 8 min read
- How long does a tank of air last?Gear & kit · 9 min read
- Deep wreck diving: where recreational stopsWrecks · 8 min read
- How a dive computer calculates no-stop timeBody & health · 10 min read
- Air, nitrox or trimix: which gas, and when?Gear & kit · 15 min read
- WWII wrecks you can dive, by theatreWrecks · 7 min read
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