Overview
Bay Marine Works provided marine support for a geotechnical investigation project in the Drury estuary as part of works for Fulton Hogan. The project required core drilling in a tidal estuary that drains completely at low tide, featuring a rocky seabed and restricted access beneath the State Highway 1 bridge.

Challenges

• Highly tidal estuary with narrow working windows
• Uneven and rocky substrate
• Low clearance and limited access under SH1 bridge
• Need for stable drilling operations in variable conditions

Solution
Bay Marine Works worked with Topdrill NZ to plan and execute a safe, efficient marine setup using Webster, a portable 10m x 3.5m drilling barge. The barge was craned into position from a purpose-built loading pad, ballasted for stability, and aligned over reinforced moonpools to accommodate drilling.
Using Mary S, a smaller flat-bottom vessel, the team manoeuvred the barge into place at high tide and secured it with hydraulic spud legs and mooring blocks. At the second drill site beneath SH1, the crew conducted precise manoeuvres between bridge piers, accounting for mast height and tidal depth to ensure safe clearance and stable operation.

Outcome
Both drill sites were successfully completed within strict tidal windows and challenging access conditions. The project demonstrated Bay Marine Works’ capability in executing safe, precise, and adaptable marine operations in complex estuarine environments.