Page 301 - Ship Construction.DJ Eyres 6Ed

Ch25-H8070.fm Page 290 Wednesday, October 18, 2006 7:00 AM

25
Cargo Access, Handling and Restraint

vessels in which palletized cargo is carried. าเท่านั้น---

งานห้องสมุด ศูนย์ฝกพาณิชย์นาวี
To speed cargo handling and storage in modern ships apart from changes in
ship design (Chapter 3), the introduction of mechanically handled hatch
covers (Chapter 19) and improved lifting devices (Chapter 24), various
patented or specially manufactured items may be brought into the shipyard
and fitted to the ship by the shipbuilder. Some notable items which fall into
this category are described in this chapter. These primarily relate to cargo
--- ใช้เพื่อการศึกษ
access handling and restraint in ro-ro ships, container ships, car carriers and

ึ
Stern and Bow Doors

Ro-ro vessels may be fitted with stern doors of the hinge down or hinge up
type which if large are articulated. Bow doors are either of the visor type or
of the side hinged type (‘barn door’ type). These are situated above the
freeboard deck and where the bow doors lead to a complete or long for-
ward enclosed superstructure Lloyd’s require an inner door to be fitted
which is part of the collision bulkhead. This would also be in keeping with
the SOLAS requirements for passenger ships where the collision bulkhead
is to be extended weathertight to the deck next above the bulkhead deck,
but need not be fitted directly above that bulkhead. A sloping weather
tight vehicle ramp may be fitted in some ships to form the collision bulk-
head above the freeboard deck and the inner door is omitted. This ramp
may extend forward of the specified limit for the collision bulkhead above
a height of more than 2.3 m above the bulkhead deck, i.e. above the
height of a conventional tween deck space. Stern and bow door strengths
are equivalent to the strength of the surrounding structure and where
they give access to enclosed superstructures they are required to close
weathertight.
Stern doors and bow visors can be mechanically raised and lowered with
wire rope and purchase arrangements but in general they and the side
hinged bow doors are hydraulically opened and closed (see Figure 25.1).
These weathertight doors are gasketted and cleated.