Special Operations.Com
Wonsan
Mine Clearance -- Underwater Demolition Team (UDT)
Activities off Wonsan, October 1950
Overview
Having failed to defend adequately against the Inchon
Invasion in mid-September 1950, the North Koreans
were not to be caught twice in that kind of trap.
Their Soviet supporters had provided thousands of
sea mines, plus technical advisors, and these began
to show their effectiveness in late September as several
U.S. and South Korean Navy ships struck mines off
the Korean east coast, with some vessels being sunk.
However, much worse was to come as the small available
minesweeping force began to clear Wonsan's approaches
in preparation for the forthcoming landings.
Mines were expected off Wonsan, and clearance operations
began on 10 October, ten days before the planned amphibious
assault. The first two days' work was encouraging,
with the minesweepers receiving assistance from helicopter
spotters, Underwater Demolition Team (UDT) personnel
and experiments in detonating mines with bombs dropped
by carrier planes. Then, on 12 October things quickly
went sour as USS Pirate (AM-275) and USS Pledge
(AM-277) hit mines and sank, with the Wonsan shore
batteries joining in to increase the misery. With
two precious ships gone, the practice of safe minesweeping
became essential, slowing progress considerably.
However, clearance activities were still on schedule,
when on 18 November, magnetic mines were discovered
the hard way as South Korean YMS-516 was destroyed
while conducting a check sweep off the invasion beaches.
That forced a postponement of landings from 20 to
26 October, while putting the surviving minesweepers
and the UDT members to a great deal more hard work,
work that continued around Wonsan through October
and well into November.
Fortunately for the UN forces, the situation ashore
was so favorable that the delay was no more than embarrassing.
The U.S. Navy, though, immediately recognizing how
a major disaster could easily have resulted, began
an urgent effort to enlarge and improve its counter-mine
capabilities. The Wonsan lesson, received at the hands
of a minor power using relatively inexpensive means,
were taken to heart by contemporary Navy policy makers.
They must never be forgotten by those whose missions
include the application of power from the sea.
Photo
Gallery
Seaman Robert H. Larking helps Seaman Raymond A.
Margozswitz into a rubber
suit on board USS Diachenko (APD-123).
The Underwater Demolition Team "Frogmen"
were preparing to destroy a North Korean minefield
in Wonsan Harbor, 26 October 1950. Photographed by
C.K. Rose, of Combat Photo Unit Two.
Underwater Demolition Team members pass
a rubber boat from the deck of USS Diachenko
(APD-123) to a waiting LCVP, 26 October 1950. They
are en route to clear mines from Wonsan harbor, North
Korea. Photographed by C.K. Rose, of Combat Photo
Unit Two.
Underwater Demolition Team swimmers
leave USS Diachenko (APD-123) to clear
mines from Wonsan harbor, North Korea, 26 October
1950. Photographed by C.K. Rose, of Combat Photo Unit
Two.
Underwater Demolition Teams One and Three board
a rubber boat from a USS Diachenko (APD-123)
LCVP, 26 October 1950. They are en route to clear
mines from Wonsan harbor, North Korea. Photographed
by C.K. Rose, of Combat Photo Unit Two.
Lieutenant Dan F. Chandler briefs
Underwater Demolition Team members on a Wonsan
beach, 26 October 1950. The "Frogmen" were
there to destroy a North Korean minefield. Photographed
by C.K. Rose, of Combat Photo Unit Two. Note rubber
swimming gear and inflatable boat.
Underwater Demolition Team "Frogmen" swim
ashore from a LCVP in Wonsan harbor, while on
a mission to destroy a North Korean minefield, 26
October 1950. Photographed by C.K. Rose, of Combat
Photo Unit Two.
Underwater Demolition Team personnel paddle
their rubber boat through Wonsan harbor, en route
to explode North Korean mines, 25 October 1950. Photographed
by C.K. Rose, of Combat Photo Unit Two.
Underwater Demolition Team personnel paddle
ashore at Wonsan, while on a mission to destroy
a North Korean minefield, 26 October 1950. Photographed
by C.K. Rose, of Combat Photo Unit Two.
Underwater Demolition Team members pull
a 300-pound rubber boat ashore at Wonsan, where
they destroyed a North Korean minefield, 26 October
1950.
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