This case about the building of two ships addressed the issue of concurrent delay drawing on authorities in the construction context.

The court rejected the ship-builder’s argument that it should be entitled to an extension of time where an employer‑caused event occurs where it is itself already in delay by reason of its own default. This contention does not fit with the requirement to prove causation in fact. It would be insufficient to show that notional or theoretical delay had occurred. The relevant extension of time clause indicated that delay had to be “occasioned by or resulting from” the employer-caused event.  

The court also adopted a working definition of concurrency being “a period of project overrun which is caused by two or more effective causes of delay which are of approximately equal causative potency”. Concurrency would only lead to an extension of time if two events caused delays to the progress of the works and the delaying effect of the two events is felt at the same time. Proof of delay must still be shown to the actual progress of the works.

The ship-builder relied on an argument that it was not necessary to justify an extension of time to show that the employer-caused event was an operative cause to the delay of the progress of the works. The court held that this did not reflect English law which requires causation in fact. Further, the court held that under English law an apportionment approach would not be appropriate.