Below the harbour

The survey team intended to record damage to the old harbour wall during a single dive. As the first diver crossed the harbour bed, disturbed silt clouded the water and hid sections of the stonework. Water loosened the adhesive on the numbered tags, allowing them to drift away from the cracks they identified. A strong current bowed the measuring tape outwards instead of letting it rest against the wall. Although the divers reported their observations through helmet microphones, noise from the support boat's engine drowned out several words. The underwater camera's battery ran out before the final section could be photographed.

Describe what made the harbour-wall survey difficult to complete. You may include brief quotations in your response.