Redondo, Palos Verdes & San Pedro · United States · Wreck
Caissons
Half-demolished concrete breakwater caisson at 49 m (160 ft)
The Caissons are ferro-cement breakwater sections built for Santa Monica and towed out and sunk south of Point Fermin in 1935 instead. Two have been found; Caisson #2, the deeper, lies at 49 m (160 ft) and was half destroyed by depth charges in 1942, leaving many nooks and crannies. It is a technical dive, not a recreational one.
Also known as Caisson #2.
Where it is and how deep
33.6571° N, 118.2682° WApproximate position — the dashed circle shows where the site lies; your operator's briefing has the mooring.
The dive
Caisson #2 sits at 49 m (160 ft) south of Point Fermin, well past recreational depth, so this is a planned technical dive. Each caisson was built as three connected semi-circles of concrete, 34 m (111 ft) long, 11 m (36 ft) high and 11 m (35 ft) wide, and Caisson #2 keeps only one and a half of them. A structure rising nearly 12 m (40 ft) off the bottom is unusual on a coast where most wrecks are broken up and low.
The depth charges left many nooks and crannies across the broken concrete, and small entry points lead into the inside sections. Growth is minimal and there is little silt or sand in the bottom of the cylinders. Going inside calls for overhead training, and gas and decompression are planned for the depth before the descent, because time on the bottom at 49 m is short.
The wreck
- Vessel
- Caisson #2 (Santa Monica breakwater crib)
- Type
- Ferro-cement breakwater crib
- Length
- 34 m (112 ft)
- Sunk
- 1935
- Cause
- Intentionally sunk for disposal after the breakwater work ended
- Lies
- At 43–49 m south of Point Fermin, half blown apart by depth charges
In 1931 Santa Monica voted to build a breakwater in front of its pier from concrete caissons made in Long Beach. The first was towed into place in 1933, but the sandy bottom scoured under it and it cracked and collapsed. On 27 May 1935 the remaining caissons were towed out to sea and sunk, and two of them have been found. On 14 February 1942 the destroyer USS Gilmer took one for an enemy submarine and dropped eight depth charges, blowing up half of it.
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 | Good | Good | Good | Good | Fair | Fair | Fair | Fair | Fair | Good |
Season follows Redondo, Palos Verdes & San Pedro: The squid run at Veteran's Park, mid-December to early March, falls in the coldest water of the year; August is the warmest month at about 19 °C.
Know before you go
- At 49 m (160 ft) the dive needs technical training, gas planning and decompression.
- Broken concrete and small entry points into the interior; only enter with overhead training and keep clear of sharp edges.
Dive videos
Tech Diving on the Caissons - 07/20/18 - Orange County Underwater Explorers - GUE · David Watson on YouTube
Questions divers ask
How deep are the Caissons off San Pedro?+
Caisson #2 lies at 49 m (160 ft), beyond recreational limits, so it is a technical dive.
Sources
- Caisson #2 (San Pedro, 160 fsw) — Wrecked in my rEvo
- Caissons — California Wreck Divers
- USS Gilmer sonar contact with caisson, 14 Feb 1942 (ub88.org) — ub88.org
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