Wreck Discovery - Read the SCUBA article

Transcription

Wreck Discovery - Read the SCUBA article
LEARNINGCURVE
Wreck discovery
Wrecks come in every shape and size, but all have certain principal features.
Charter skipper Bob Anderson sheds some light on the machinery you are
likely to see, painting a picture of what can be found on a typical wreck
he sea does strange things to time. As
soon as a ship slips below the waves
her history is paused and a new future
starts governed by the salty water and
other destructive forces of nature.
The coast of the UK is littered with
wrecks: Ian Whittaker’s book Off Scotland
charts the position of every recorded wreck
in Scottish waters as a black dot on a white
sheet of paper. The coastline can clearly be
traced from this information alone. Wrecks
are the very raison d’être for many who
dive, yet they are strangely misunderstood.
In my mind, much of this confusion arises
because people complicate wrecks more
than necessary.
The way to understand and interpret a
wreck lies in simplifying the structures
common to all vessels and having an
understanding of their role in the ship. Most
divers jump off a boat to get to a wreck, so
a simple glance around before you jump can
help. There is a wealth of information about
most sites that can be soaked up before
entering the water so, in many ways, a
wreck dive should be a confirmation of
T
50
what is already known rather than a voyage
into the unknown. Underpinning everything
is a simplicity of function that really brings
things alive.
Three-castle steamships
A good starting place is the classic
steamship. The Sound of Mull has several
firm favourites and the Shuna and the
Hispania rank as among the best in the UK.
Usually with a tonnage of around 1,200 and
about 80m long, these ships were built to
carry a bulk cargo, commonly coal, in a
number of cavernous holds. On top of the
hull were three castles (a term inherited
from old sailing ships): the forecastle or
fo’c’sle at the bow, the bridge and engine
room in the middle, and the poop at the
stern. Underneath lie the engine spaces and
cargo holds, which take up the majority of
the space on the ship.
A hull has a design speed at which it will
efficiently cruise through the water, which is
a function of waterline length. Yachts and
warships tend to be long and sleek in order
to maximise speed, while steamships favour
a more bulbous, bellied hull to maximise
internal cargo carrying capacity. The bows of
both the Hispania and the Shuna in the
Sound of Mull are bluff, flat-nosed affairs
that flow to the full beam of the ship swiftly
with little hydrodynamic grace. Yet at the
stern, these ships have a beautiful curve that
is a characteristic snapshot of their age, a
shape that has all but gone from modern
ship design.
Dropping over the stern rail of a ship and
down to the prop and rudder always
conveys a good sense of scale. There is
nothing quite like seeing the blades of a
massive prop to make you feel small.
RAbove: Rising up the bow of a classic
steamship, Norway's Helga Ferdinand
However these often, large lumps of
valuable non-ferrous metal are easily
removed and so many are simply not there.
The Shuna, luckily, has a ferrous prop and so
it remains.
UBelow: The typical layout
of a three castle steamship
The bow and anchors
The front island, or fo’c’sle, is a legacy from
fighting ships of old where there literally
was a castle at the bow that allowed archers
to fire down on the enemy. This part of the
ship slowly evolved into the bosun’s stores
below deck and the anchor winch topside.
The Shuna’s crew attempted to run the
ship up the beach and hold her there on the
anchors. Sadly they failed and the ship
slipped back down the slope to where she
ILLUSTRATED MARINE ENCYCLOPAEDIA 1890, PAASCH, H
lies today. The evidence for this story is there
today as the rusty remains of the anchor
chains can just be made out in the silt at the
bottom of the bow and the anchors are not
housed in their normal positions.
Ships’ anchors are generally stowed in the
sides of the hull at the bow. The chain goes
through the hawse pipe, from the outside
of the hull to the deck, running over thick
rubbing plates to the anchor windlass. From
the winch it will run over a gypsy (which is a
shaped ‘wheel’ that raises the chain as it
turns) before running down a spurling pipe
down into a chain locker where it is stowed.
The main remains of the modern wreck of
Lunokhods in Shetland is a bow section that
has snapped off from the rest of the ship g
51
LEARNINGCURVE
RAbove: A diver is
dwarfed by the massive
iron blades of the Shuna
g but,
despite the modern details, it shows
that the principles of anchor stowage have
remained unchanged.
The bosun’s stores in the bow are usually
in a compartment just below the anchorhandling area and frequently hold
interesting arrays of ship parts or other
stores. In both the steamships in Lerwick
harbour, the stores still have the remains of
blocks wires, ropes and other tackle slowly
rusting away.
I always like to swim off a wreck at the
g
SBelow: The stern of the Hispania is a
flow of beautiful lines
RAbove: The Lunokhods is a modern ship but
the principles remain the same: a diver
illuminates the anchor winch while a rope drum
to the left tidies away the warps while at sea
RAbove: The bows of the Glen Isla sail out of the depths – there is no better feeling
than slowly rising up the bow of a classic steamship
52
g
LEARNINGCURVE
g bow
before turning and looking back.
There is often a panorama to soak in that
gives a full sense of the ship and her
character.
The cargo and holds
Within the hull lies the cargo. Coal is the
most common find, as it is a bulk
commodity needing to be moved in large
quantities over considerable distances. The
Shuna has holds full to the top, still fully
laden even on the seabed.
Of far more interest is a ship with a good
variety of mixed goods such as the Breda.
Twelve divers can happily scratch around the
holds like hens in a pen, searching for some
RAbove: Exploring the coal
in the holds of the Shuna
of its vast array of goodies, each wrapped in
their own smoky cloud of silt.
Salvage plays a part in what you see of
the holds, as the manifest was often the
most valuable component of a ship. The SS
Buitenzorg, which lies deep in the mouth of
the Sound of Mull, was salvaged and the
hatches from the holds were ripped open,
releasing the bundles of raw latex rubber
which then slowly floated to the surface.
The bundles could take hours to reach the
surface, by which time the tide had taken g
SBelow: A naked hermit
RAbove: A squat
crab runs across a pile of
white bathroom tiles
lobster has made his
home from gas mask
eyepieces fallen from
their rubber mask
SBelow: Bicycle tyres slowly rot in the
hold of the Breda
RAbove: An anemone
has found a home on a
tube of rubber glue
55
LEARNINGCURVE
g
them miles from the site: many locals will
tell the tales of setting off in hot pursuit.
The bridge
The middle castle on our idealised steamship
is the bridge atop the main accommodation
area. It is well worth visiting the SS Great
Britain in Bristol where there is a bridge from
one side of the ship to the other that forms
a raised platform for command, which
shows the origin of the term very well.
This is one area that has changed beyond
recognition over the years. In times past
there would have been a single sailor
steering a ship by compass at a solitary
wheel, whereas modern ships can have a
bank of complicated electronics forming a
wall of monitors that the skipper does well
to see over.
On wrecks, the bridge draws divers in with
the glitter of brass. Many of the favoured
items for salvage are grounded in this area,
from compass binnacles to the ship’s wheel
and other brass bounties. The steering
binnacle from the Glen Isla, for example, has
been recovered and is now in the Shetland
museum; the feet are formed from three
dolphins, a popular theme of the time.
Many ships had a wooden bridge on top
of a steel accommodation block so often
the only indication is the solitary helm
posting and the central boss of the wheel, a
lonely sentinel on the roof of the wreck.
In many ways, it is the crew area below
the bridge that holds most interest. The
stubs of table legs emerge from the mud,
debris such as drawer fronts and other bric-
SBelow: Exploring
the triple expansion
steam engine of the
Glen Isla
a-brac rise tantalisingly out from the ooze.
Behind the mess, is usually a bathroom area
with tiled floors, sinks and baths with taps
hanging from the walls. If there ever is to be
a touch of humanity on a wreck, it lies here.
The engine room
The engine room is one of the few places
you can see the technology of the day
stopped and frozen in time. Admittedly all
the parts are corroding and slowly falling
apart but these are not sterile museum
surroundings: with care you can wriggle
among the exposed con rods, trace the
SBelow: A steam
SBelow: Swimming
engine before time
and salt take a toll
between the boilers
of the steamship
Gwladmena.
ILLUSTRATED MARINE ENCYCLOPAEDIA 1890, PAASCH, H
pipework and, if you are lucky, see the
engineer’s spanners sitting next to the vice
on a workbench. There is a Fred Dibnah
within us all that can see the aesthetic, if
not mechanical beauty in a place where
form truly follows function.
The Shuna has an often-overlooked
engine room that many manage to miss,
in the less than glowing viz that shrouds
the wreck. Yet this is a gem of an engine,
all the parts laid as they were in service
with room to shine a torch around corners.
Further north, the Glen Isla stands out even
more: all the components are visible from g
57
LEARNINGCURVE
TBelow: Though slightly
reshuffled by the ravages of
time, all the major organs of
the Gwladmena are on show
from the engine in the front
to the two boilers behind
PRight: Shetland is eclipsed
by some of the wrecks in the
colder Norwegian waters.
Here a diver peeks into the
open hatch of a steamship
engine room
UBelow right:
Auxilliary steering wheel
at the stern of
Norway's DS Tyrifjord
g
the boilers to the engine, pipework, valves
and engineer’s cabin.
The stern
In the past, the aft castle was the poop deck
from which the boat would have been
helmed. However this function has moved
forward to the bridge over time, as the tiller
has given way to a wheel. Yet the area often
still holds some form of emergency auxiliary
steering above the rudder shaft.
The picture of the Breda that I like the
best shows her from the stern steaming
through what I imagine to be the Suez
canal. I picture a salt worn Dutch seaman
pausing for a cigarette over the stern rail
before throwing the stub into the ship’s
wash with a rasping cough and the slow
drawl of a man too long from land and too
battleworn to go home. The stern is very
characteristic on the Breda and it is easy to
58
59