A Master Guide to Hatch Cover Maintenance - Eric Murdoch [2002, PDF]

A Master Guide to Hatch Cover Maintenance

Year: 2002
Language: english
Author: Eric Murdoch
Genre: Guide
Publisher: Charles Taylor & Co. Limited
Format: PDF
Quality: eBook
Pages count: 30
Description: It is generally accepted that leaking hatch covers are a principal cause of cargo wetting.
Hatches leak for a variety of reasons, but mainly because of poor maintenance or failure to close
them properly. Leaking or badly maintained hatch covers can lead to more serious consequences
than wet cargo – flooding, accelerated corrosion or even loss of the ship. These problems are
addressed in the guide.
During investigation and discussion we have found a degree of confusion throughout the industry
as to whether hatches are constructed to be watertight or weathertight. A watertight hatch cover
is a cover designed to prevent the passage of water in either direction under a head of water for
which the surrounding structure is designed. A weathertight cover, is a cover designed to prevent
the passage of water into the ship in any sea condition. Hatch covers are constructed to be
weathertight, which means that, in any transient condition, water will not penetrate into the ship
through the covers or the double drainage system. However, it is apparent that minor leakage into
a cargo hold during a hatch cover test is often erroneously considered to be within a weathertight
standard; in practice, no leakage is the requirement. For this reason, we include guidance on
procedures for conducting leak detection tests on hatch covers.
From our research we have the impression that many mariners think hatches are robust,
monolithic structures, thereby failing to appreciate the small tolerances on panel alignment
and gasket compression.
For example, 4mm wear on the steel-to-steel contact is sufficient to damage rubber sealing
gaskets beyond repair; 5mm sag along the cross-joint can cause a large gap between the
compression bar and gasket.
It is better to think of hatches as complex, finely-made structures, to be handled with care.
It is the aim of this guide to explain the key issues of hatch cover security and to steer mariners
towards active maintenance. It is less expensive to keep hatch covers weathertight by regular
maintenance and attention to detail, than to pay claims for wet-damaged cargo. It is crucial for safety
at sea and protection of the environment to maintain hatch cover weathertightness and strength.
This guide concerns steel hatch covers fitted with cleats, compression bars and gaskets.
Eric Murdoch
Director of Loss Prevention
Charles Taylor & Co. Limited
1st January 2002