Both media and research focus has been put on
the risk posed by sunken ships off the Swedish coast. One especially media
friendly collection of wrecks are the wrecks on the Swedish Exclusive Economic
Zone (EEZ) off the island and lighthouse Måseskär (west of Orust on the Swedish
west coast). After World War II German ships were sunk there by the allies, the
ships were filled with German ammunition and chemical weapons. The number of
ships, the amount of ammunition, what type of chemical weapons and so on is
unclear. After reading reports from the latest investigations on site (Swedish
Maritime Administration, 2015) it is clear that it is bad. However, the claims
made over the last 20-30 years by journalists about the number of ships and
amount of mustard gas is most probably exaggerated and a result of unreliable
secondary sources. But let us not focus on those issues because the problems
are real no matter what.
The work localizing and learning more about the
wrecks off Sweden is an intriguing mix
of diving, ROVs, archive searches, risk analysis and classic detective work. It
thus includes an important, challenging and close cooperation between
researchers and practitioners. It is from 2016 decided that the (new) agency Swedish
Agency for Marine and Water Management (SwAM or HaV in Swedish) is responsible
for the coordination of the work and late 2016 the first wrecks will be
investigated for oil and emptied if oil is found. The first wreck to be drilled
for oil is the Thetis in the Skagerrak. The SwAM is also aiming for IMO to ban
fishing around the ammunition ships off
Måseskär on the Swedish EEZ.
The list of
the most prioritized wrecks (the emergency to-do list) also include ships in
other positions than off the Swedish west coast. One is just of my home island
where I and many others often passes over it on the fairway to and from
Stockholm. It is the cargo ship Harburg, she collided February 16, 1957 with
the tanker Tinny. Harburg sank fast and 10 men were killed. Tinny of 16450 DWT,
loaded with gasoline, was on her way to Stockholm and hit Harburg amidships and
probably caused the boiler to explode and tare the ship up from inside. The
collision pushed Harburg down under Tinnys keel. Harburg sits on approximately
30-37 m depth about 180 meters from shore. The ship is broken just in front of
the first cargo hold with the bow lying flat on the ground and the aft part of
the angle from the bottom. Harburg has previously leaked oil.
An
interesting side story to this investigation is that neither fishermen nor fish are
stupid ;-)
While on
site the Swedish Maritime Administration used both side scan sonars and ROVs to
investigate the wrecks. What was evident from the sonar data was that the
waters are often used as fishing ground for bottom trawling. From the tracks it
is clear that the fishermen knows the positions of all the wrecks and to a good
job dragging the trawl in-between as shown on the picture below.
 |
| Tracks from bottom trawling. (C) the Swedish Maritime Administration, 2015. |
However,
also the fish seems to have grasped the important aspects of the situation and spend
their time cramped together just around the wrecks. This is evident from the ROV
reports as there was problems getting any shots of the wrecks and cargo onboard
as a result of all the fish. (Sadly the Swedish Maritime Administration does
not publish the pictures with the fish, the focus on the wreck. However, you
can find fish also on those pictures as shown below.) I suspect that the fish
has analyzed the fishermen's activity and now make sure to spend their time
where they are out of reach for the trawlers...
 |
ROV and side scan sonar pictures. Note the weapons on the ROV pictures and around the ships on the sonar picture, but also the fish on the top left picture. (C) the Swedish Maritime Administration, 2015.
|
Reference
Swedish Maritime Administration, 2015. Miljörisker sjunkna
vrak II, Undersökningsmetoder och miljöaspekter [Environmental risks from
sunken wrecks II, Investigation and environmental aspects]. Dnr:
1399-14-01942-15. Swedish Maritime Administration
