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Four Mile Rock Barges


Well marked on nautical charts since the early 70’s, the Four Mile Rock Barges lie near the 100’ depth line about a quarter mile offshore from Four Mile Rock. Situated just below the Magnolia Bluffs in Seattle, this advanced boat dive was recently in the news as a possible source of “burping oil” seeping into Elliott Bay.

The coast guard investigated the wrecks, and divers found no sign of seeping oil. Indeed, on my recent dive to these two barges, it is apparent that these are both bulk carriers, which have no storage tanks to even hold any seeping oil. An old report suggests that a barge sunk at this location in a collision with the Astorian in 1926, but it is apparent from the condition of the wrecks (which are very good) that they are much more recent (perhaps the older barge is buried below them).   Approximate GPS coordinates are:  47°  38.4' N   122°  25.7' W, but its easy to find on a depth sounder.


The barges lie roughly parallel to each other, with about 50 feet between the sides. The barges themselves are about 200 feet long, 50 feet wide and perhaps as tall as 20 feet off of the bottom. The deepest part of the wreck would be the stern of deeper barge, which is just over 100 feet deep at the mud line. The shallower of the two barges lies in only 75 feet of water.


Both barges are draped with layers of abandoned fishing nets, still killing, year after year. Care must be taken, as the fishing nets, along with some cave line left over from training exercises, poses an entanglement hazard for divers visiting this site. This is a good site for wreck training, as well as for those more advanced recreational divers that are comfortable with the 80-100 foot depths. However, there is a lot of commercial shipping and boat traffic in the area, so fly a dive flag and pay attention to the current.


We spotted several species of rockfish and greenlings around the wreck, which is covered with large metridium anemones, as well as the usual sea stars, nudibranchs and other local invertebrates. My dive buddy, Craig Miller, proved to be an excellent model during our dive, posing for several pictures. As an added bonus, he was diving his KISS rebreather, so I didn’t have to “wait” to take his photos….no bubbles. Very cool!

The large stabilizing fins on the stern of the barges make a great “Cavern” swim through. These are fun to carefully cruise through, parting the schools of rock fish while using careful fin techniques to make sure your buddy doesn’t swim through a silt-out! All in all, a pleasant dive within sight of downtown Seattle.