Advanced seabed surveys underpin safety at Perth SailGP

A comprehensive 3D survey of the seabed off Fremantle was completed to enhance safety for competitors and event officials at the inaugural Perth Sail Grand Prix (SailGP). Using state-of-the-art mapping technologies, the Department of Transport and Major Infrastructure (DTMI) of the State of Western Australia produced seabed data at a level of detail not previously achieved for an aquatic event in the state.

Seabed assessment formed a key part of SailGP’s approval process, with DTMI evaluating potential safety risks both above and below the waterline before granting approval for the event at Bathers Beach on 17 and 18 January.

Drone-based Lidar survey

According to DTMI Maritime Coastal Information Director Jenny Bothma, the survey introduced a new approach to seabed investigations. Technicians combined conventional hydrographic sonar data, used to determine water depths, with high-resolution Lidar captured by drones to map above-water features, resulting in a more complete picture of the event environment.

The result was a very detailed 3D computer model of the racecourse and surrounding seabed showing known areas of concern including the location of the enduring underwater piles of the original Fremantle Long Jetty extending west from Bathers Beach and also the depth of water around the breakwaters at South Mole and Challenger Boat Harbour.

“The model is an invaluable resource for organizers to use to identify hazards and eliminate safety risks,”  Bothma said. “The new, very detailed data not only gives organizers greater confidence to safely manage this large international event, but it also provides valuable additional information for DTMI’s nautical chart for the area – boosting ongoing safe navigation by commercial and recreational craft.” 

Shipwreck locations

The survey also delivered enhanced detail on the locations of known shipwrecks off Bathers Beach, with this information already shared with the WA Museum.

DTMI worked closely with SailGP to ensure robust safety management plans were in place for both race days, as well as for all aspects of staging the event at Fremantle Fishing Boat Harbour (FFBH).

In its role as harbour manager, DTMI collaborated with event organizers to coordinate access to ticketed viewing areas at South Mole and Bathers Beach, allocate space for support vessels and racing craft, and manage the large crowds of visitors and locals who attended the event.

Explore DTMI’s 3D seabed model here. This interactive model, along with other bathymetry datasets, is available via DTMI’s WA Bathymetry Portal.