HATCH COVERSCLAIMS v/s MAINTENANCE
P&I Loss Prevention Bulletin
Vol.53

July 2022

CONTENTS
1

INTRODUCTION …………………………………1

2 HISTORY OF HATCH COVERS ………………3
3

RULES & REGULATIONS …………………………7

4

HATCH COVERS ……………………………… 15

4-1 DESIGN ISSUES ………………………………… 15
4-2 RELATIVE MOVEMENTS & ACHIEVING TIGHTNESS … 15
4-3 KEY PARTS ……………………………………… 18① Hatch panels & Coaming plating ……………… 20② Packing rubbers …………………………………… 22③ Bearing pads………………………………………… 26④ Locators ……………………………………………… 28⑤ Stoppers ……………………………………………… 29⑥ Securing systems ………………………………… 30⑦ Drain systems ……………………………………… 33⑧ Compression bars ………………………………… 35⑨ Operating systems ………………………………… 36

5

MARINE TAPE:
A BLESSING OR A CURSE ? …………… 39

6

EVIDENCE IN CASE OF CLAIMS ……… 42

7

HATCH COVER TESTING ………………… 43

8

MAIN PROBLEMS FOUND………………… 44
Common mistakes …………………………………… 44
Weather tightness mistakes ………………………… 45
Mechanical mistakes ………………………………… 45
Hydraulic mistakes …………………………………… 45

9CONCLUSION …………………………………… 46

Chap.

01

INTRODUCTION

A recent study and claims analysis carried out by the Japan P&I club over a 5 year period between 2016PY and 2020PY shows that out of the 161 claims that were reported,
76% consisted of wetting damage to grain, steel and ore cargoes.

In 74 cases (46%), the sea water damage was caused by leaking hatch covers. This once
again shows that hatch covers continue to generate seawater induced claims and that improperly maintained and leaky hatch covers have a high claim potential.
Grain

54

Steel

40

Ore

28

Others22

Fertilizer

9

Plywood, Timber, etc.

4

Reefer

2

Log

2

0

10

20

30

40

50

60

Graph 1 Number of Sea Water Damage on Bulk Carrier,General Cargo Vessel 2016PY-2020PY

When water susceptible cargo comes in contact with seawater during an ocean passage,
it is most likely that a claim for wetting damage will be filed against the ship by the cargo owners/receivers.

These claims generally consist of a financial compensation for the damaged cargo, but
indirect consequences associated with wetting damage claims, such as extra work for1

legal staﬀ, survey costs, delays, sorting and reconditioning of the damaged cargo, unscheduled repairs to hatch covers, reputation damage, disruption of the ship’s operational schedule, travel costs for superintendents, … can be significant as well.

Whenever a claim for damage to 3rd party property is introduced, it is incumbent on
the club to defend the owners’ interests and successful settling will mainly depend on
proving that the hatch covers were well maintained and that the shipowner and Master
exercised due diligence to ensure that the hatch covers were in good condition at theoutset of the voyage. It is sad to see that many of the claims filed for wetting damage
could have been successfully defended and settled if only the owners and crew would
have carried out basic hatch cover maintenance in line with good industry practice. The
seas and oceans are a hostile environment and rigours of an ocean voyage should never
be underestimated. Hatch covers are designed to withstand the perils of the sea but only
when they are well maintained, they will be able to keep water out and cargoes dry.

Despite awareness campaigns in the past, hatch covers remain a major driver for wetting
damage claims. Water infiltration may not only be a safety issue for the vessel and crew
on board, but it also scuttles the business model of carrying goods by sea and should be
avoided at all times.

The importance of correct hatch cover operation, maintenance and repairs cannot beemphasized enough. This loss prevention article, written by industry leading expert Mr.
Walter Vervloesem (FNI) of IMCS bv (Belgium), will highlight key issues that should
be well understood and observed in order to reduce exposure to ingress, wetting damage
claims and to allow the club to defend your interest with success.

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Chap.

02

HISTORY OF
HATCH COVERS

Since ancient times, diﬀerent kinds of floating objects have been used for transporting
goods over water. Initially trees, rafts and canoes were used, but gradually, and with theindustrial revolutions over the last centuries, we have seen an evolution and transition
from floating objects to wooden ships and more recently to steel vessels.

Over the last decades a wide variety of specialized and sophisticated ships appeared on
the maritime scene in order to satisfy demand of world trade or to carry out specific marine tasks and operations.
The most commonly seen ships nowadays can be categorized as follows: container
ships, bulk carriers, tankers, roll-on roll-oﬀ vessels, passenger/cruise vessels, oﬀshore
vessels, fishing vessels, speciality vessels, high-speed craft and dredgers.
Roughly 80-90% of the world trade is being done by a total of 119,999 cargo ships ofwhich 28,647 ships (23.8%) consist of dry cargo vessels, i.e. general cargo ships andbulk carriers, which represent 38.2% of the gross tonnage of the worlds’ fleet.
Ratio of cargo vessels in the world trade

Ratio of general cargo/bulk carriers

OthersOthersCargo vessels

Dry cargo vessels

80〜90％

23.8％

119,999 vessels

28,647 vessels / 119,999 vessels

3

Typically water sensitive cargoes like grain, steel, fertilizer, ores etc are transported on
dry cargo vessels. In order to allow a swift intake and facilitate easy discharge of theabove commodities, these vessels are equipped with hatch covers.

In case large amounts of water should penetrate the ship’s hatch covers, both ship and crew
could be in danger but limited water ingress would normally not cause a safety problem
for the ship.
However, from a cargo quality point of view, even small amounts of water can ruin a cargo
and cause commercial havoc. In general, one can say that the Class and statutory rules andassociated inspections will mainly look to the safety of the vessel and crew. The industry(charterers, shippers, receivers, underwriters,…) will take statutory and class compliancefor granted and will focus more on the commercial aspects of carrying goods by sea.

Whilst decades ago, only a few types of hatch covers were made, a wide variety of hatch
covers were being developed to accommodate the requirements of specific ships, trades
and cargoes. Nowadays, the most commonly seen types of hatch covers for general cargoships, handysize, panamax and capesize bulk carriers consist of folding hatch covers (general cargo & handysize) and side rolling hatch covers (panamax & capesize). For container
vessels we generally see that lift-away type pontoons are installed.

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Ultimately it will be the shipowner who will decide, in concertation and dialogue with the
shipyard, classification society, flag administration, customers,… which hatch cover type will
suit the client’s business model best and eventually hatch covers that are right for the ship,trade and cargo will be developed around a number of key parameters. Items that may influence the design are amongst others size of hatches, carriage of deck cargoes, strength requirements, available crew for preparing hatches to go to sea, opening/closing methods,……

Hatch cover designs have evolved from vary basic and relatively lightweight designs tohuge, heavy and moving pieces of equipment. Hatch covers are generally referred to as
heavy-duty shipboard equipment and this is generally associated with material that canwithstand rough handling and does not need constant care and maintenance. However,this is not true as modern hatch covers are high-tech equipment for which very small tolerances should be observed. Their maintenance is type-specific and their operation should be5considered a risk. Therefore, having a good understanding of how hatch covers work, andhow to maintain and operate them is very important.

Cargo should not only be carried and delivered in time and in good condition but should
also be transported in an environmental friendly manner. In view of the size and weight of
hatch covers, many types are still operated by hydraulic systems which, in case of failure
and associated spillage, have a pollution potential.

Only the combination of proper inspection, correct operation and regular maintenance ofhatch covers will ensure that the goods loaded onboard ships can be transported in linewith good industry standards.

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Chap.

03 RULES & REGULATIONS
In view of their impact on the safety of the ship and crew, hatch covers should comply
with diﬀerent rules and regulations imposed by Class, Flagstate (statutory) and Industry.
As already pointed out in Chapter 2, Class will be working together with owners andshipyards during the development, design and manufacturing process and supervise installation of the hatch covers on board. Furthermore, the vast experience and knowledge
from Class, reflected by the Class rules, will generally ensure that hatch covers can be
type approved and, once installed, be in compliance with ruling regulations.

Throughout the in-service life of the ship, Class will carry out regular inspections toensure that the approved design of the hatch covers has not been altered, modified orchanged and that the hatch covers are still fit for duty. This could be the case when (temporary) repairs to the hatch covers were carried out by the crew after they suﬀered damage or when the crew thinks that so-called “improvements” should be made to facilitate
or enhance operations, closing, sealing or securing.

Most shipboard staﬀ are not aware of the fact that such modifications cannot be madewithout the consent of Class (and/or flag state) who previously approved the hatch cover
design. Failing to bring repairs or modifications to the attention of the Classification society might result in Class being withdrawn (even post-factum in case of an incident).

In many cases, flag states will delegate their responsibility for inspections to Classification societies which will then be allowed to act as a “recognised organisation” and carryout tests and inspections required by the conventions to which the flag state is signatory
party.

7

Conventions that are ratified by the flag state have to be included in the flag state’s maritime law and as such they will become statutory instruments. Finally, and besides theClass and statutory requirements, which are both aimed to guarantee the ship’s seaworthiness, there are also requirements that are imposed by industry players such as charterers, P&I clubs, transport insurers, vetting organisations,….

Industry requirements are based on the fact that a ship, once inspected and certified by
the Class and flag state, will be compliant with Class and statutory rules and therefore
technically fit and able to sail.

Extra requirements imposed by the industry will be focussing more on the commercial and quality aspects ofthe trade and might include requirements related to fumigation, ventilation, ultrasonic testing of hatch covers,
cargo, cleanliness, ….

Whilst safety of the ship is paramount, claims will seldom be introduced on grounds of unseaworthiness of thevessel but rather on non-compliance with the industry

Photograph 1
Hatch pontoon, fallen into

requirements or commercial related issues (cargoworthi-

cargo hold on bulldozer

ness) such as leaking hatch covers (and wetting damage
to cargo), condensation damage, delays for opening/closing hatch covers, stevedore
damages,…..

Under the terms and conditions of a charter party, owners will be required to provide aseaworthy ship. A seaworthy ship is a ship that is technically fit (re-structure, certification, performance,…), cargoworthy (suitable to lift and transport the intended cargo) and
fit to undertake the forthcoming voyage (incl. bunkers, crew, provisions, spare parts,…).

Practically speaking, and in case of cargo damage as a result from water ingress via

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improperly maintained hatch covers, it will be concluded that the hatch covers were notsuch that the cargo could be transported without risk for damage and that therefore theship was not seaworthy from a cargo carrying point of view. Such a verdict will usually
be made after inspection and testing of the hatch covers and when it is proven that thehatch covers were indeed not in good condition at the outset of the voyage. In such acase, owners will be blamed of not having exercised due diligence.

International convention on loadlines (ICLL):
With regards to the ship’s hatch covers, the ICLL is first and foremost the most important convention. Loadlines and draft marks are normally used to determine how muchcargo has been loaded which, from a commercial point of view (charter party andfreight) is very important.

However, from a Loadline convention point of view, not the cargo loaded, but the freeboard (the part of the ship that is out of the water for a specific draft) is of paramountimportance as it determines the ship’s reserve buoyancy and safety. The more freeboard,the more reserve buoyancy the ship will have and the safer the ship will be. This is why
the Loadline convention clearly states that “The load line shall never be submerged at
any time when the ship puts to sea, during the voyage or on arrival”l (Art. 12).

Under the Loadline convention, openings that are above the waterline are required to be
weathertight. This actually means that water that is coming from the weatherside (suchas green seas, sprays, rain,…) should not penetrate into the ship via these openings. If
this should happen, water, and therefore weight (each m³ of sea water weighs 1.025 ton),would be added to the ship which will cause the ship to be deeper in the water with lessfreeboard as a result. In order to prevent wateringress and be considered weathertight,
the ICLL requires the closures of these weathertight openings to be structurally soundand strong, tight and well secured.

9

“Weathertight means that in any sea conditions water will not penetrate into the ship“(Reg. 3-12). (from the weatherside)

As the ship’ hatches are huge openings, which, in case of failure or leakage can admit
substantial amounts of water to the ship’s holds, it is clear that every eﬀort should bemade to ensure that hatch covers are tight and will remain tight during the voyage.

Weathertight should not be confused with “watertight” as watertight means that “water
will not pass through the sealing arrangements from both directions across the seal undera head of water” (in both directions). Therefore, a closure between two compartments
below the waterline should normally be watertight. Watertight compartments are resistant to water pressure, as is the case during a major water ingress. Thanks to the “watertight” closure, the leakage will not spread, and the vessel will stay afloat.

As the Loadline convention is a statutory instrument, overloading the ship (and therefore
willingly reducing the ship’s freeboard and reserve buoyancy), is not allowed and constitutes an infringement against the maritime law of the flagstate.

Finally, the Loadline convention requires that “The means of securing weathertightness
shall be to the satisfaction of the administration” and “The arrangements shall ensure

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that the tightness can be maintained in any sea condition and for this purpose tests fortightness shall be required at the initial survey and may be required at periodical surveys
and at annual inspections or at more frequent intervals” (Reg. 16-4)

As ICLL compliant hatch covers should prevent water entry, they have to be strong, tightand well secured. Whilst tests are merely carried out to ensure that the sealing arrangements are in order, it is clear that apart from testing, a visual inspection should be carried out as well in order to determine that the hatch cover related structure and securing
arrangements are in order. A satisfactory test alone is not a substitute for a careful visualinspection of the hatch covers and in order to confirm that hatch covers are weathertight,
and will remain weathertight throughout the voyage, both a test and a visual inspection
are necessary.

Other conventions and regulations
Whilst the ICLL is the most important hatch cover related convention, other importantconventions apply to hatch covers as well. It is beyond the scope of this article to highlight all possible hatch cover related rules and regulations but some important hatch cover related conventional issues are listed below:| SOLAS |Owners responsibility of maintaining the ship, exemption for fixed fire fighting, carriage of dangerous cargoes (IMDG – dangerous when wet), pesticides (fumigation), ISM (risk, accidents, damage to property), specific safety measures for bulk
carriers.

| MARPOL |Pollution from hydraulic oil, grease,…

11

| MLC |Safe working, familiarization & training| The Code of Safe Working Practice for Merchant Seafarers (COSWP) |Hatch cover safety guidance.

Hatch cover type approval
It should be noted that hatch covers are designed and type approved by the classificationsociety. Such a type approval confirms that the hatch covers, when properly maintained,
are in conformity with the ICLL, applicable rules and regulations and therefore able towithstand the rigours of an ocean voyage.

In case of damage, any repairs, other than day-to-day maintenance, that might have an
impact on the hatch cover design and approval criteria, should brought to the attentionof the Classification society and/or flag state as this will allow studying of the intended
repairs or modifications and determine if the earlier given type approval is not aﬀected.
Also Class will be able to advise on correct repair requirements, welding methods andtechniques. In case lashing terminal points (stoppers, D-rings,…) are welded on thehatch covers or coaming, it is best to call in the advice of Class. Not doing so may jeopardize the vessel’s Classification status.

Commercial and charter party issues
Under the Hague-Visby rules, Article III, the carrier shall comply with the below 3 main
issues when signing a contract of carriage:

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The carrier shall be bound before and at the beginning of the voyage to exercise due diligencegto:（a）Make the ship seaworthy;（b）Properly man, equip and supply the ship;（c）Make the holds, refrigerating and cool chambers, and all other parts ofthe ship in which goods are carried, fit and safe for their reception, carriage and preservation.

From a hatch cover point of view, it is considered evident (and required) that hatch covers are in a good condition and in compliance with Class and statutory requirements (seeitem a)) whenever a charter party or contract of aﬀreightment is signed. However, withregards to supplies (item b)), necessary spare parts for the hatch covers (which can beconsidered as critical equipment) should be placed on board. This is important to maintain weathertightness during the voyage in case hatch cover parts should become damaged. Furthermore, under part c), hatch covers will have to be inspected and maintained
so that the cargo loaded in the holds will not suﬀer wetting damage.

In order to prove that due diligence was exercised (i.e. by doing everything that is practically possible and reasonable to ensure that the hatch covers are fit and in order for theforthcoming voyage) owners will have to document actions taken to ensure that hatch
covers are in good condition.

Quite often a satisfactory ultrasonic or hose test will be considered as suﬃcient proof
that the hatch covers are in order. However, the main issue is not if hatch covers can passa test (there are plenty ways or “tricks” to pass a test, even if the hatch covers are not ingood condition), but if the hatch covers are weathertight and will remain weathertightduring the voyage in order to preserve the cargo and avoid water ingress. As pointed out
above, this also requires a thorough visual inspection to confirm that the sealing capacity of the hatch covers, as proven by a satisfactory test, can be maintained throughout thevoyage. During such a visual inspection, all parts that contribute in maintaining a tight13

seal (e.g. bearing pads, locators, stoppers, cleats, drains,…) should be inspected in accordance with manufacturer’s instructions and good industry practice.

Unfortunately, till today, and despite of what is mentioned above, we often see that charterers, shippers etc are requesting surveyors to carry out ultrasonic (or hose) tests in order to confirm that the hatch covers are in order (to start loading operations, take a vessel“on-hire”,…). Such an instruction – carrying out a hose or ultrasonic test alone – will
indicate that the hatch covers are not leaking at time of the test, but will not give information on whether or not due diligence has been carried out and if the necessary hatch
cover parts are in a good condition to ensure that tightness can and will be maintained
during the voyage. Considering a satisfactory hatch cover test in port alone as suﬃcient
proof that hatch covers are weathertight and will remain weathertight during the voyage
is dangerous and might give a false sense of security.

It should be noted that hatch covers are designed and type approved to withstand therigours of an ocean voyage and face the ordinary perils of the sea. Only when conditions
that are beyond the design (approval) criteria are met with, i. e. extreme heavy weather,
freak waves etc, it is accepted that some water might enter into the ship, but not to suchan extent that the safety of the ship and crew would be at stake. However, as stated before, even small amounts of incoming water may ruin a cargo and so it is possible thatwater susceptible cargo might suﬀer wetting damage.

In case of a claim being filed for wetting damage, owners and ship’s crew should ensurethat the hatch covers are able to withstand detailed scrutiny (visual inspection) and passa hose or ultrasonic test. This will make it clear that the wetting damage claimed is not
the result from improperly maintained hatch covers and can therefore only be the resultof extreme weather conditions being met with during the voyage. In such a case, thewetting damage can be referred to as “Act of God”/“Perils of the sea”, which will allow
redirecting of the claim towards the cargo underwriters.

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Chap.

04

HATCH COVERS
4 1 DESIGN ISSUES

Designing hatch covers that are in compliance with the required rules and regulations andat the same time meet with the shipowners expectations (type and size of vessel, maintenance requirements and repair possibilities, carriage of cargo on hatch covers, budget, …)
is a diﬃcult and challenging task and in many cases compromises will have to be made,however, always by keeping in mind that “weathertightness can be maintained in any sea
condition” (ICLL (reg. 16(4)), so that the safety of the ship and crew is not at stake.

With owners’ requirements in mind, designers and manufacturers will then consider issues like type and construction (open web type, double skin, corrugated, flat topped/peaktopped), required stowage space, sealing type and systems, type of operation, weight,
securing mechanisms, …

Once a suitable design has been defined, the plans will be submitted to the Classificationsociety and/or administration who will study and eventually approve the design.

4 2 RELATIVE MOVEMENTS & ACHIEVING TIGHTNESS
A ship is often compared with a steel box. Although a steel box is quite rigid, the box
becomes flexible once the cover (deck) is removed or when large openings are cut into
the deck (hatchways).

15

In order to prevent water ingress in the holds, and to keep the cargo dry, holds have to
be covered up with hatch covers which are required to be weathertight. Furthermore,
and in order to withstand the forces acting on the hatch covers due to weather conditions(weatherload) and twisting and flexing of the hull whilst the ship is on passage, and by
taking into consideration that carriage of deck cargoes may be required, hatch covers
need to be strong.

Whilst at sea, the strong and rigid hatch covers will not move in unison with the flexible
hull of the ship and hence relative movements will occur which will enhance the risk forwater ingress.
Typically, these relative movements, which are the result from weatherloads, ice pressure, flexing, hogging, sagging, twisting and a combination thereof when the ship is atsea, will take place in way of the packing rubber and compression bar interface (hatch
cover & coaming and between adjacent panels).

Figure.1 Illustrating relative movements between panels. (Courtesy MacGregor)

It is therefore important to identify/determine the relative movements and to installcounter measures that will prevent ingress. By installing a soft and flexible packing rub-16

P&I Loss Prevention Bulletin

Vol.53ber in the hatch covers, the resilience of the rubber will compensate for these relative
movements and preclude water ingress. However, there may be situations where thepacking rubber alone will not be able to keep water out. This would be the case when
the packing rubber’s design compression (see later in this article) would not be suﬃcient
to compensate for excessive relative movements at a given moment as might be the caseduring hurricanes or impact of freak waves etc..

Even in such extreme cases, and according to the ICLL, the weathertight integrity should
not be impaired and water should not enter into the ship’s hold. Therefore, and in orderto achieve compliance, manufacturers will install drain systems i.e. drain channel above
the packing rubber/compression bar interface in cross joints to evacuate water from theinterpanel void space ("A" - Figure 2) as soon as possible and a drain channel ("B" Figure 2) underneath the packing rubber/compression bar interface which will evacuate
incoming water that passes through the rubber/compression bar interface and prevent
water from falling into the hold.

Obviously, and when the ship is facing heavy weather, it cannot be avoided that some of
the water that collects in the drain channels is spilled over the edge of the drain channel andfalls in the hold on the cargo stowed underneath, leading to wetting damage to the cargowith subsequent claims as a result.

Photograph 2
Water spilled over the edge of the drain channel and fell on the cargo stowed underneath.

17Whilst the rubber packing and drains are of key importance in keeping water out, it is
the hatch cover steel plating that will keep most of the water out and therefore assessing
the condition and structural integrity of the panel (and coaming) plating is very important as well.

①
Steel to steel contact

A②
Rubber seal③

B

Figure.2 Showing the 3 safety barriers in hatch cover design,i.e. the steel hatch plating ① , the sealing system ② and the drain channel ③

In summary, we can now say that designers and manufacturers will install 3 safety barriers in order to reduce the risk of water ingress to acceptable level (see Figure 2).

4 3 KEY PARTS
With hatch covers being equipment that can weigh up to 100 MT or even more and spanvery large openings, it is clear that hatch covers will only meet with expectations andwork well when they are correctly made, installed, maintained and operated.

Apart from the fact that the hatch panel (and coaming) plating, packing rubbers anddrain systems will keep the water out, relative movements during the voyage will require

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additional equipment and key parts that will keep the panels in place, prevent the distortion of the panel geometry and secure the panels to the ship. As per the ICLL requirements, “The arrangements shall ensure that the tightness can be maintained in any sea
condition”and “The load line shall never be submerged at any time when the ship puts
to sea, during the voyage or on arrival” (Art. 12). In other words, no water shall enter
into the holds. This means that during an inspection in port (where it is usual for inspections to be carried out), one should not only be focussing on whether or not the hatch
covers are able to pass a tightness test, but also on judging if the condition of the hatch
cover parts as found during the inspection will allow to maintain tightness (and keep thepanels in the required sealing position) when the ship is at sea. This further clarifies thatcarrying out a test of the hatch cover sealing arrangements alone is not suﬃcient andwhy a visual inspection is paramount when weathertightness has to be confirmed.

Hatch covers are complex and delicate pieces of engineering which work against verysmall tolerances and clearances which are all in the range of millimeters. In view of thesize and shape of hatch covers, such small tolerances are diﬃcult to check or confirm
with the naked eye and therefore measuring equipment such as tapered feeler gauges,

Photograph 3 Using feeler gauges, yardsticks and depth gauges during an inspection

19depth gauges, calipers, piano wire (or laser), yardstick etc…. should be in the inspector’s
toolbox.

① Hatch panels & Coaming plating
Hatch panels (panels and stiﬀeners) and coaming plating (side plating, coaming table
and coaming stays) keep most of the water out and have to be able to withstand the impact of waves, weather and cargo loads and as such their structural integrity needs to beassessed at regular intervals. Furthermore, many load bearing parts such as bearing pads,
stoppers, locators, cleats, trackways etc… welded onto the hatch panel and coaming table make assessment of the structural integrity of the panels and coaming table a priority
item. Inspection should focus on the following items:●

Advanced corrosion

Advanced corrosion will affect thestrength of the structural members
and plating. Preventing the eﬀects
from corrosion starts with good
maintenance and proper (and timely) painting. Besides being a cosmetic issue, painting is an eﬃcient
way to counter the devastatingeﬀect of exposure to weather conditions and abrasive cargoes. Visualinspection and thickness measurements will confirm that the plating
is still suﬃciently thick and strong.

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Photograph 4
Advanced corrosion to hatch panels

●Physical damage

Physical damage (cracks, holes,
deformations) as a result fromstresses (caused by twisting,hogging/sagging, coaming deflection, overloading/improper weightspreading, improper adjustment/alignment of the panels) but also
stevedore damages may aﬀect thehatch coverʼs structural integrity.

Photograph 5
Stevedore damage to hatch panels

Therefore, hatch covers should be
inspected for damage after loading
and discharge operations and thecause of cracks and deformations
should be investigated.

●

Temporary repairs

Temporary repairs or shipboard
made lashing terminal points suchas stoppers and D-rings. Exposureof hatch cover and coaming structure to heat may cause thermal
deﬂections and improperly made repairs may aﬀect type approval andnot be in accordance with requirements or good industry practice.

Photograph 6
Welding D-rings on hatch covers

21●

Presence of rust streaks and leakage traces.

Whilst the external hatch coaming
plating is prone to the same damages as the hatch top plating (corrosion, cracks, deformations…), theinner hatch coaming may show thewhich is prima facie evidence thatwater has been inﬁltrating throughthe hatch covers.
Photograph 7
Evidence of leakage traces on innerhatch coaming plating② Packing rubbers
Packing rubbers are fitted in retaining channels that are part of the hatch panel and constitute importance reference material when it comes to hatch panel adjustment. Packing
rubbers should be flexible part and provide suﬃcient resilience to compensate for the
relative movements between the panels and panels and coaming.

Whilst often considered to be just “a piece of rubber” packing rubbers have to remain
flexible and be able to withstand exposure to heat, cold, sunlight, cargo (abrasive/chemicals, …), chlorides, etc. as long as possible during their in-service life. On condition thatthe hatch covers and packing rubbers are well maintained, rubbers will normally age
slowly and at a steady pace and easily remain in good shape for a 5 year period.

Various types and designs of rubber packing are available. Part of these designs are theso-called ordinary/box type rubber packings which act on a raised steel compression bar,whilst the other type is the “sliding profile” seal which act on a flat steel mating surface.

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Types of rubber packings

Flex seal
sea
Photograph ８

CA
CAT
AT
T sealSpongeponge seal
sea

Flex seal, CAT seal and sponge seal

Packing rubbers are designed with a certain design compression (see photographs below) which is generally in the range of 8-20mm. This design compression correspondswith a certain reaction force (line compression) which allows the packing rubber to respond properly and quickly to relative movements in order to keep and maintain a tightseal.

Figure 3 Showing packing rubber specs as per the manufacturerʼs manual

It is important that the packing rubber is compressed to its correct design compression
since over compression will lead to damage and permanent set of the rubber, whilst
insuﬃcient compression will cause the seal to lose contact with the compression bar inless severe weather conditions and allow for water entry.

In order to check if a box-type packing rubber is overcompressed and permanent set excessive, and without a manual being available, the following rule of thumb can be used.

23

Design compression = 25% of the nominal thickness of the packing rubber
Discard criteria= 50% of the design compression

70
Design compression: 10mm
（25% of thickness）
Discard criteria: 5mm（50%of design compression）

Rubber size：
70mm × 40mm
Design compression：
40 25% of thickness = 10mm
Discard criteria：
50% of design compression = 5mm

So for a 70x40mm packing rubber with a design compression of 10mm, 5mm of permanent set will be the limit for replacement. In case of the normal type of CAT seal, around shaped profile, instead of the triangular one, indicates that the packing rubber isnearing the end of its in-service life.
Packing rubbers are normally correctly compressed up to their design by the weight ofthe panel and not by overtightening the cleats!

Photograph 9 Overcompressed CAT seal

Although often considered to be good practice, crew should refrain from “lubricating”
packing rubber with grease like substances such as petroleum jelly, ordinary grease etc

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P&I Loss Prevention Bulletin

Vol.53