Expedition Update: M-24 Midget Sub – May 2017

On Saturday 13 May 2017, after waiting for weeks for a suitable weather window, team divers Matt Carter and Steve Trewavas commenced the first project dive of the extended expedition. Assisted by able surface crew on the boat, ANZEC members Peter Fields and David Strike the team were greeted by flat seas and still winds. Visibility from the surface was tremendous and the water azure blue. The current was noticeable on decent, and diver propulsion vehicles (DPV) enabled the dive team to locate the wreck which was within 4m of the shot line. Visibility on the bottom was in the region of 6-8m noticeably worse than during the decent (30m).
At a depth of 56m, Matt commenced mapping the wreck utilising his Suex DPV and the attached camera mount and lighting system. At the completion of the mapping runs several photos were taken utilising the Hugyfot Camera System to document the current state of the wreck.


Figure 1. The M24 Japanese Midget Submarine at 56 metres, note the abundant fish life. Photo Steve Trewavas.


The wreck was then photographed in its entirety to supply the Agisoft Photoscan Software with the best opportunity to merge the photos and video into a 3D photogrammetry model. The dive was turned at the 40-minute mark, and the divers spent an additional 70 minutes decompressing from depth to the surface.


Figure 2. Matt Carter at the centre of the submarine illuminating the conning tower. Photo Steve Trewavas.



Figure 3. Matt Carter at the bow of the submarine showing the remains of the upper torpedo tube. Photo Steve Trewavas.


June 1st will mark the 75th anniversary of the sinking of the sub and it is in remarkable condition for having been submerged for so long. The major features of the wreck including the torpedo tubes, conning tower and propellers were readily recognisable to the team during the survey.

As an archaeological site of international significance, a No-Entry Protected Zone of 500 metres radius has been enforced around the site since its discovery in 2006. As our project is a strictly non-disturbance archaeological survey of the wreck site a permit was issued by the NSW Heritage Division, Office of Environment and Heritage (OEH). Once completed, all information from the survey will be provided to OEH to aid them in managing and interpreting this fascinating wreck site.



Figure 4. From left, David Strike, Peter Fields and Matt Carter fly Explorers Club Flag 192. Photo Steve Trewavas.


About Author


Steve is an immediate prior National Director of the Cave Divers Association of Australia (CDAA)and a previous CDAA Training Director. He is an avid Photographer both above and below water. He is a technical rebreather diver with a keen interest in documenting our unique global environment. His most recent endavours have been focused on leading expeditions to the caves and aquatic environment of south central China. He has undertaken two flag expeditions - Cocklebiddy cave and he is currently a team member on a flag expedition to document the M24 Japanese mini submarine.

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