Lessons learned: sounding pipes must be free of debris or cargo – SAFETY4SEA

In its series of hatch cover incidents, the Swedish Club provides lessons learned from an incident where water entered Hold 1 of a bulk carrier, causing water damage.

The Incident

A bulk carrier had a full cargo of zinc concentrate on board and was sailing from the west coast to the east coast of South America. As the ship passed Cape Horn, she experienced severe Beaufort Scale 9 weather with green seas covering cargo covers 1, 2 and 3. This continued for four days as the ship battled the waves. The ship had no weather route.

When the weather calmed down, the master asked the first officer to inspect the cargo holds. The chief mate discovered that water had entered cargo hold 1 and caused water damage. No water had seeped into the other holds. The chief officer also inspected the hatch coaming and the hatch cover of hold 1 and found a crack in the hatch coaming. The drain pipes from the non-return drain valves were also filled with debris and cargo.

probable cause

During unloading, the surveyor noted that the sounding pipes in the cargo holds were also clogged with debris. When the ship was alongside and the cargo hatch covers were removed, puddles of water were visible in Hold 1. It took several additional days to remove the wet cargo from the ship and most of the cargo was refused by the buyer.

Lessons learned

  • Sounding pipes should be free of debris or cargo, as they are important for sounding before loading and during the voyage.
  • It is important to know that zinc concentrate can liquefy if shipped with a moisture content above its Transportable Moisture Limit (TML) according to the IMSBC code. Puddles will obviously exceed the TML.
  • It should be a job for the PMS to check that the drain hoses and drain valves are not clogged and that the float (ball inside) moves freely.
  • Hatch covers and coaming steel structures are heavily loaded members. Their condition has a direct effect on the carrying capacity and safety of the vessel. Steel construction should always be inspected after an unusual loading case, and there should also be regular checks in accordance with the PMS.
  • When repairs are made, only classification society approved steel should be used. High tensile steel is commonly used for cargo hatches and coamings.
  • The classification society must be contacted before carrying out any structural steelwork repairs.
  • The weather route should be considered as it provides the ship with the ability to avoid severe weather, but also ensures that ships receive a new updated ETA to the port of discharge. This helps shipboard crew, shore personnel and cargo owners to plan accordingly