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Four Mile Barges
Topography: Two large upright steel barges situated on a flat substrate of sand and small rocks.

Puget Sound marine life rating: 3

Puget Sound structure rating: 3

Diving depth: 90 feet

Highlight: Two massive steel barges that are frequented by schooling vermilion rockfish.

Skill level: Advanced

GPS coordinates: N47° 38.403’  W122° 25.631’

Access by boat: These barges are almost directly west of Four Mile Rock. Four Mile Rock is a couple miles southeast of West Point and is easily distinguished by the large green navigation marker on top of the rock. These massive barges are located a ways offshore but relatively easy to find with a depth sounder. I circle the GPS coordinates and wait for my depth sounder to reveal a 20 foot jump in the GPS coordinates are for the bow of the eastern-most barge.
Shore access: None

Dive profile: These steel barges are very large - about 150 feet in length from bow to stern and maybe 40 feet wide. They both sit upright and intact in about 90 feet of water with their decks about 20 feet above the substrate. The two barges rest somewhat parallel to one another. The western barge rests with her bow pointed south while the eastern barge lies with her bow pointed northeast.  The barges are only about 30 feet apart at the south end.  I can usually see the white glow of the giant plumose anemones clinging to the western barge from the end of the eastern barge if visibility is halfway decent..

I do not stray far from the barges as the substrate in this area is relatively flat and featureless. I am careful to note my anchor’s position relative to the barges so I know where to find the ascent line at the end of the dive. I can usually circumnavigate both barges before running low on no-deco time if I am breathing Nitrox.

The barges were covered in derelict fishing nets the last time I visited this site. I am always careful to stay clear of the nets. I carry two knives and a set of shears as insurance.  Some of the steel decking has rusted away in places so you can get a glimpse of the interior of the barges. Most of the deck area on the barges is flat and featureless.  I therefore spend most of my dives examining the sides and base of the barges, which is where the majority of the marine life conjugates.

My preferred gas mix: EAN 36

Current observations:

Current Station: Admiralty Inlet
Slack Corrections: None

I have never noted a strong current at this site, but I only dive this site at or around slack on low to moderate exchanges (less than 2.2 knots maximum current at Admiralty Inlet).

Facilities: None

Boat Launch:

Don Armini boat ramp (West Seattle). Approximately 4 miles from dive site.


Depth: This is a deep dive with a relatively square dive profile that requires careful management of air supply and no-deco time.

Free ascent: A free ascent from 65 feet (the tops of barges) is necessary if the anchor line is not acquired at the end of the dive.

Snagging hazards: Derelict fishing nets blanket parts of this wreck. Snagging hazards inherent to a steel wreck also exist.

Exposed location: This site is far from shore and offers no protection from wind or weather.

Boat traffic: Heavy boat traffic frequents this area, especially during boating season. Shilshole and Elliot Bay marinas are nearby.

Fishing boats: Four Mile Rock is a popular fishing area during salmon season.

Navigation: Proper compass operation may be effected by the iron in these steel wrecks.

Marine life: I am always impressed with the marine life I find at this site. The massive structure of the barges offers refuge for a number of creatures not normally found in the immediate area. I normally encounter small schools of red vermilion rockfish loitering about barges. Joining the vermilion rockfish are quillback, copper and brown rockfish, small lingcod, and painted and kelp greenlings.

The sand flats immediately surrounding the barges often host unusual and colorful creatures. I sometimes find beautiful sand rose anemones and elegant giant nudibranchs.

Plumose anemones and metridium add brilliant color to the otherwise drab wreck. Some anemones have figured out how to attach themselves to the nets, which creates quite an interesting spectacle.