Question 1

In the example valve arrangement described in the ABS notice, how can a vessel ballast or de-ballast through the bypass route even without the ballast pump running?

Accepted Answer

By gravity — if valves on each side (e.g. V01 & V02, or V03 & V04) are opened simultaneously, water can flow through the bypass line by gravity alone, with some designs providing no alarm for this condition This is precisely why ABS's first recommendation is for crew to evaluate ALL possible bypass scenarios, explicitly including gravity-driven ballasting/deballasting, not just pump-driven scenarios — a purely pump-focused review would miss this route entirely.

Question 2

What is the core PSC deficiency being raised in ports under the Tokyo MoU concerning BWMS arrangements?

Accepted Answer

The piping arrangement may permit the ballast water management system to be bypassed during ballast uptake and discharge operations without activating an alarm The deficiency centres specifically on undetected bypass capability — valves that allow ballast water to be taken on or discharged without passing through, or being recorded as bypassing, the treatment system.

Question 3

Under Section 7.2 of the BWMS Code (Resolution MEPC.300(72)), what is required of any bypass or override fitted for ship/personnel safety in an emergency?

Accepted Answer

It must be connected to the BWMS so that any bypass activates an alarm, and the bypass event must be recorded both by the control/monitoring equipment and in the Ballast Water Record Book Section 7.2 explicitly requires that any bypass connected to and used in conjunction with the BWMS triggers an alarm and is recorded both electronically and in the Ballast Water Record Book — this is the dual-logging, dual-alarm requirement at the heart of the issue.