Technically, a shipwreck is a vessel that sank accidentally. And, since the sinking of the Yukon happened “accidentally on purpose” one might argue that the vessel is not an authentic shipwreck. What’s more, it’s outfitted with “fake” propellers and guns. But ask any diver that’s explored the Yukon and there’s no denying — the thrill of diving here is quite real. The dive site Yukon is a gem of Southern California diving.

California Diving News
But let’s take a step back and tell the whole story. The Yukon sinking was the culmination of a multi-year effort of dozens of movers and shakers in the diving and tourism industries and over a hundred ordinary folks in diving as well as the San Diego Ocean Foundation. Unable to obtain a ship from the decommissioned U.S. Naval fleet, the group went to Canada to obtain a suitable vessel. What they came up with exceeded the expectations of many — the 366 foot-long Canadian destroyer escort Yukon. At considerable cost, mostly from private donations, the ship was cleaned and made “diver-safe” and prepared for sinking. This painstaking process took several years and lots of man-hours, with much of the work performed by volunteers. With holes cut in her hull and throughout the ship for easy diver entry and egress, and explosives set for her final demise, she was towed out to a well-surveyed location 1.85 miles off Mission Beach for sinking on July 14, 2000. But Mother Nature intervened. High winds and waves came up the night before and in the wee hours of the morning, waters sloshed into the carefully hewn holes in her side and she succumbed to the ocean, sinking hard on her port side. So now you know.
It is remarkable what nature and the ocean can do in just a few years. A thin layer of marine life growth enveloped the ship almost immediately. Shortly thereafter more substantial encrusting animals moved in and crabs, other invertebrates and fish followed including schooling fish and scorpion fish on the hull along with painted greenlings, cabezon and others. Predators like halibut and lingcod inhabit the sand and nook and crannies near the bottom. 
Perhaps the most interesting marine life is the fluffy white football-sized Metridium farcimen anemones that dot the wreck and in some places blanket the hull and superstructure. Much smaller are the Corynactis californica anemones forming a carpet patchwork of warm colors along most of the ship. The mantle covering the wheelhouse creates a great photo opp around what use to be the portholes.
The entire ship is exciting to explore but two spots are favorite of many — the “propellers” and the forward “guns.” The props look odd because they are not normal propulsion propellers but rather training devices that were used dockside to teach Canadian sailors on proper operation of the ship’s engines while still dockside. They are covered with beautiful corynactis anemones and nudibranchs are common here. The forward guns look real enough but the barrels were replaced before sinking with dummy pipes to simulate the guns. 
As previously mentioned, several large holes were cut into the hull prior to sinking making penetration possible — but only with proper training. Never, ever enter an overhead environment without proper training and equipment. Bring a light to gaze into the cavernous hull. One can drop down into the hull and look out the gaping holes but be aware that even in just a moderate swell there will be a strong surge “suction” in and then a powerful force of water spitting you out. Judge the power by observing the small kelp sprigs as they are pulled in and out.
This is an advanced dive, with the shallowest portion of the wreck at about 60 feet, with bottom depth just over 100 feet. Most of the wreck can be explored at depths of about 80-85 feet. Currents are usually moderate but can come up suddenly and with gusto. Several permanent mooring buoy lines are attached to the wreck. Plan to descend and ascend using the lines or you risk being blown off the site by strong currents. And always carry signaling devices just in case.
The Yukon is just one of several spots to explore in the area off Mission Beach, now referred to as “Wreck Alley.” Charter boats visiting the area will often dive the Yukon first and then progressively move to the shallower sites like the Ruby E wreck and the NOSC Tower wreckage. 
At-A-Glance 
Location: 1.85 miles off Mission Beach, San Diego, in an area known as “Wreck Alley.”
Access: Boat.
Depth: 60-102 feet.
Skill: Advanced to technical if planning wreck penetration.
Visibility: Varies widely, but averages 15-25 feet or greater.
Photography: Excellent macro and wide-angle opps.
Hunting: Not prohibited by law, but generally frowned upon.
Conditions: Expect moderate to strong currents.
California Diving News