... and Depth
Multiple echoes
These are caused by the transmitted pulse being reflected several times
between the sea bed and the water surface before its energy is dispersed.
Such multiple reflection ... same
barometric pressure.
Isotherms
These are lines drawn on a weather map to connect areas of the same
temperature, and they may also be used to express the sea or air
temperatures.
29Speed ......
... use as a grease
cavity.
Double and treble sheave purchase blocks are of a similar construction to
the single sheave, except that a partition plate separates the sheaves. They
are used extensively ... RIGGING
STEEL WIRE ROPE
A steel wire rope is composed of three parts – wires, strands and the
heart. The heart is made of natural fibre, though recently synthetic fibre
has been used when resista...
... used to sleep in the
fo’c’sle head area, and the banging cables tended to keep them awake.
Hence they were lashed secure.
The more up-to-date thinking is that if the cable is lashed the chance
of ... secured when
the anchor is deployed.
Deck plate
Doubler
Underdeck frames
Hawse pipe (tubular
steel)
Bolster (steel)
‘D’
‘D’ represents the diameter of the
hawse pipe and is at least nine
times th...
... be secured at the head of the sheer legs and
the weight taken. Care should be taken to ensure that men brace themselves
against any movement of the shoes in the process of raising the legs
when ... tubular
steel. Wooden derricks, which generally lifted only up to 3 tonnes, have
largely been superseded.
At the heel of the derrick (Figure 5.1) either a single flange or a
double flange will be w...
... Once the slip and bottle screw
are released, the gripe can be passed back over the boat and the end
cleared. However, some gripes are interconnected to the trigger system,
and the men in the boat ... weak link securing which
will part after the painter becomes fully extended and the pressure
increases, causing the safe working load/breaking strain to be exceeded.
‘D’
ring
Service
release
De...
... Checks that
rudder indicator
shows maximum port
helm
Ease the wheel to Ease the wheel to Allows the wheel to Wheel eased to
port ten degrees port ten degrees, return towards the port ten degrees,
sir ... What are the main differences between the construction of
a flexible steel wire rope and a non-flexible steel wire
rope?
Ans. A flexible wire will have more wires per strand and a fibre
heart...
... the vessel may be expected
to roll somewhat slowly and independently of the waves. The vessel will
probably experience only moderate angles of roll, and the waves may be
expected to break near ... between the two vessels shall not
make the overtaking vessel a crossing vessel within the meaning of these
Rules or relieve her of the duty of keeping clear of the overtaken vessel
until she is ......
... Seamanship Techniques
Red
Green
Vessel less than 50 m in length
restricted in her ability to manoeuvre.
Green
Red, white, red,
all-round lights
shown where they
can best be seen.
Red
Range 2 miles
Head ... can
Green
Green
Conical
Spar
Pillar
Red
Green
Red
Red
Green
Preferred channel to starboard, red with green stripe, and
red light flashing 2 + 1 (group flashing).
Green
Red
Green
Green
R...
... derricks been lowered or removed?
(d) Where applicable, have portable pipes been removed
and have the remaining open ends been blanked off?
(e) Are rope messengers to hand for securing the helicopter
if ... considerable time to secure. In an emergency it may even prove
impossible to secure against water pressure on one side.
Regular and extensive maintenance is required on the clips to ensur...
... other, preventing the steering problems
experienced by the single screw vessel (see Figure 9. 9).
A distinct advantage of twin screws, apart from the increased speed
created, is that if the steering ... Side
This term refers to that side of the vessel exposed to the wind. Seas may
be seen to break over the weather side as opposed to the lee side, which
is the sheltered, favoured side of the...