Which test methods are accepted?

Three methods are recognised: hose test (water jet at minimum 2 bar, 1.5 m distance, 100 mm nozzle), ultrasonic test (an ultrasonic transmitter inside the closed hatch + a receiver outside detects gaps), and chalk test (chalk on packing rubber + close hatch + open and inspect transfer pattern). Hose and ultrasonic are quantitative; chalk is qualitative and used as a condition-monitoring tool, not for class approval.

Why does this matter?

Weathertight hatch covers are the primary barrier between sea water and the cargo hold. Failure causes cargo damage claims (heated steel, wet grain, mould-affected timber) which run to seven-figure sums on a single voyage, and in extreme weather can cause progressive flooding. Marine insurance and P&I cover routinely scrutinise hatch-cover survey condition before settling cargo claims.

How often must hatch covers be tested?

IACS UR S26 requires a hatch-cover examination at every annual class survey including a check of the operating gear. A water-tightness test is required at intermediate and renewal special surveys (i.e. every 2.5 years on average). Owners often test at every loading port for sensitive cargoes (grain, project cargo, steel coils) regardless of class schedule.

What is the role of the cargo securing manual?

The cargo securing manual (CSS Code, IMO Resolution A.714(17)) details the hatch-cover load capacity, sequence for closing, locking arrangements, and weight limits for cargo on top of the covers. PSC inspectors check for loaded cargo on hatch covers exceeding the rated point load — a common deficiency on ageing bulkers.

Hatch cover testing

IACS Unified Requirement S26 and the International Convention on Load Lines 1966 (with the 1988 Protocol) require hatch covers to be weathertight and structurally sound. Three test methods are accepted by class — hose test, ultrasonic test, and chalk test. Each has different sensitivity and is used at different points in the survey cycle.

Hose test

· Water jet directed at the joint between hatch cover and coaming, hatch panels, and side seams.
· Minimum pressure 2 bar at the nozzle (pressure gauge required); 1.0–1.5 m distance from the joint; 100 mm nozzle diameter.
· Inside person watches for water ingress at the rubber packing, locator pins, cleats, side cleats, and quick-acting closing devices.
· Cannot be used at sub-zero temperatures (water freezes); ultrasonic test substitutes.

Ultrasonic test

· Ultrasonic transmitter (~40 kHz) placed inside the closed hatch.
· Receiver wand swept over every joint, packing rubber, and weather shield from outside.
· Gap detection threshold typically 1-2 dB above ambient; equipment must be calibrated and the operator class-approved.
· Quantitative leak-rate measurement; preferred method for grain, project cargo, and condition assessment.
· Standards: ISO 17840 + class society approval scheme (e.g. DNV CMP, LR ShipRight).

Chalk test

· Chalk applied to the packing rubber along its full circumference.
· Hatch closed and locked under normal cleating force.
· Re-opened; inspected for chalk transfer to the compression bar — a continuous transfer mark indicates correct compression; gaps indicate poor packing condition.
· Qualitative only; used as a routine maintenance check by the deck crew rather than class evidence.
· Performed at port stays before sensitive cargoes; recorded in the deck log.

Inspection points

Packing rubber — set, hardness (target 70±5 Shore A), continuity, no gouges, no permanent deformation.
Compression bar — straight, no corrosion, no bend; clean of paint or debris.
Locator pins, cleats, quick-acting devices — operate freely, no seizure, lubricated, locking pins in place.
Hatch panel structure — UTM gauging at intermediate/renewal survey; deflection ≤6 mm under load (IACS UR S21).
Drain channels — clear, valves operate; non-return flap in place.
Coaming — corrosion limit per IACS Common Structural Rules (CSR-BC), typically 25% original thickness.

Common findings

· Packing rubber compressed flat (no rebound) — replace.
· Cleats with seized threads, cannot reach correct torque — overhaul.
· Deformed or wasted compression bar — straighten or renew.
· Drain holes clogged or non-return flap missing — clear and replace.
· Locator pins worn, hatch panel sits at angle — renew pins/bushings.
· Coaming top wasting near scupper — class consultation required.

Sources: IACS Unified Requirement S26 (Strength and weathertightness of hatch covers and coamings of cargo holds and tanktops); International Convention on Load Lines 1966 (as modified by the 1988 Protocol); IMO Resolution A.714(17) (CSS Code); ISO 17840 (ultrasonic testing for hatch cover weathertightness). See also scantlings, Load Line Certificate, IACS classification.

Last verified 4 months ago