Exploration of the YMS 359

On Saturday April 19th 2008 Scott Christopher, a Seattle area NAUI Technical Dive Instructor, and “Northwest Grateful Diver” Bob Bailey dove the wreck of the YMS 359. The YMS 359 was a YMS-1 Class Auxiliary Motor Minesweeper : Laid down September 12th, 1942 by Robert Jacob Inc., City Island, NY; Launched April 9th, 1943; Completed August 20th 1943.  It was struck from the Naval Register February 7th, 1947.  It was then sold January 6th, 1948.  The vessel was sunk in the middle of Lake Washington straight out from Carillon Point, Kirkland, WA at a depth of 200 feet.

The ship has the following specifications : Displacement 270 t.; Length 136'; Beam 24' 6"; Draft 8'; Speed 13 kts; Complement 50; Armament one single 3"/50 gun mount; Propulsion two 880 shp General Motors diesel engines, two shafts.

YMS359-Profile-2008-04-19.gifThe dive team descended to 190 feet and tied in a primary reel.  The ship was located within seconds. Then Scott Christopher carefully tied off the primary reel mid-ship and lead the teams exploration toward the bow section.  The wreck is in fair condition.  There are several side compartment panels that have been removed that will allow easy access for future penetration.  This wreck was easy to identify as the military numerical markings are still present on each side of the ship.  The Starboard side was explored from mid ship to the bow.  The team continued exploration around the bow, surveying the upper portion of the port side of the vessel.  The cabin structure is still clearly identifiable.

This wreck is covered with exploration line that was left, either by careless explorers or abandoned due to an emergency that arose.  Our dive team operations will plan a future expedition to this site in order to remove this unwanted and potentially deadly hazard.  Our goal is to restore this vessel to the original condition in which it sank.

Fifteen minutes in to the dive, the team turned and headed for the ascent line.  An object that looks like a bath tub, lying on its side, was located on the starboard side of the top deck.  Upon locating the ascent line, Scott Christopher gently removed the primary reel from the ship and the team started their ascent.  Bob Bailey called the decompression for this dive.

Ben Griner acted as a safety diver and met the primary dive team at 70 feet.  Ben made certain the primary team was squared away and surfaced to inform the captain for the day, Shaun Gardner, that everything was going according to plan below.  Ben rejoined the team at 50 feet. Ben experienced a primary light failure, so the team tightened formation for the remainder of the decompression.

The primary team spent 20 minutes on the wreck and 30 minutes decompressing.  Gas mixes used on this exploration were 18/45 for back gas, 50% and 100% for decompression.  The weather topside was 44 degrees, exactly the same as the water at 200 feet in Lake Washington.  Surface conditions were calm.  The team spent an additional three hours using a side scan sonar unit and located two additional potential targets for future dive operations.  A truly great day on (and beneath) Lake Washington.