The Ruby E is adorned with colorful marine life, but alas, the grand old lady is beginning to show her age. After all, she’s been serving as an artificial reef since 1989. And she was no spring chicken when she was sent to the bottom, having been built in 1934. She had first seen service as a U.S. Coast Guard cutter under the name Cyane. Her later occupation was that of a salvage vessel under the name Ruby E. Eventually too old and obsolete for further service above the water she became a perfect candidate as an artificial reef. Today her superstructure is showing signs of crumbling, so now’s the time to go see this old gal while she’s still in full grandeur.

California Diving News
The Ruby E was the second vessel intentionally sunk off Mission Beach, in what is now known as San Diego’s “Wreck Alley.” The kelp cutter El Rey was the first, sunk in 1987. The famous 366-foot Yukon joined them in 2000.
Shallower and smaller (165-feet in length) than the Yukon, the Ruby E can be explored thoroughly in just one dive, yet it will stimulate you in a way to keep you coming back for more. And because it is a shallower dive, it is the perfect dive as a follow-up to the deeper Yukon.
The sinking in 1989 was flawless — almost. She just refused to submit to the sea. With multiple gaping hatchways left open for easier diver exploration, valves were open to the sea and the Ruby E was expected sink quickly. By mid-afternoon it was obvious she was not going to go without a fight. Pumps were brought in to fill the ship and by later afternoon, stern first, with a hiss and gulp, she was on the 85 foot deep bottom sitting nearly upright with the top of her wheelhouse just 50 feet down. 
The marine life takeover was almost immediate. Within just a couple of years a patchwork of colorful fingertip-sized corynactis anthozoans decorated most of the hull. Stars, nudibranchs, crabs, and other invertebrates followed suit. Small fish like gobies moved in, as did their predators — cabezon and scorpionfish. And finally groups of blacksmith, perch and schooling fish found a home moving about the upper structures. 
A yellow buoy usually marks the wreck. On descent down it is most tempting to start your dive around the superstructure, which is one of the most interesting parts of the ship. But I suggest you start deep and work your way shallower. In the shadow of the wreck in the sand you will likely find sheep crabs and halibut. At the stern, if the shifting sands allow, you can look over the two bronze propellers, now forever still.
Moving to the back deck you will find open hatchways leading to the cargo holds. Bring a dive light to take a peek. Internal exploration, however, is not recommended as the decaying steel has left behind a great deal of silt and sharp metal edges. 
Moving forward you’ll find yourself at the hatchway to the engine room. Within the engine room are the two massive engine blocks still in place.
 
The wheelhouse is a favorite spot for exploration. Light streams through the many portholes and cavities now rotted into the bulkheads. As much as it is tempting to enter the superstructure, do so at your own risk. The wreck is no longer stable.
Divers abide by an agreement not to hunt on the wreck, but that does not stop hook and line fishers, so be sure to bring a sharp knife or other cutting tool in case you meet up with monofilament entanglements. While exploring the Ruby E it’s almost as important is to bring a dive light for poking around and an underwater camera to document the beauty that comes with age. 
At-A-Glance 
Location: Approximately 2 miles off the Mission Beach Jetty. 
GPS N32°46.035′, W117°16.612′. Usually marked with a yellow buoy.
Skill level: All with good visibility. Only the most experienced, properly trained and equipped divers should attempt penetration.
Diving depths: 85 feet to the bottom, 50 feet to the top. 75 feet average dive depth.
Visibility: 5 to 40 feet, averaging 15 to 20.
Access: Boat only. Many dive charter boats out of Mission Bay serve Wreck Alley and there is a boat launch ramp for private boats.
Hunting: Gentlemen’s agreement to not hunt here.
Photography: Excellent macro with lots of small animals. Wide angle is good but depends on water clarity. 
California Diving News