INQUEST: A joint inquest is underway in Gladstone into the sinking of FV Cassandra (pictured) and FV Dianne.
INQUEST: A joint inquest is underway in Gladstone into the sinking of FV Cassandra (pictured) and FV Dianne.

VESSEL SINKING INQUEST: Architect reveals how ship sunk

A NAVY architect gave evidence into the joint inquest of two sunken fishing vessels and possible causes of how a 17m commercial trawler capsized, taking its skipper and deckhand to the depths.

The ongoing inquest held at the Coroners Court at Gladstone continues to shed new light into the tragic sinking of fishing vessels, Cassandra off the Fraser Coast on April 4, 2016, and Dianne off Seventeen Seventy on October 16, 2017.

Skipper Matthew Neil Roberts, 61, and crewman David Barry Chivers, 36, remain missing and it's suspected they also died in the sinking of Cassandra.

During the inquest several issues have been raised as to the management of the vessel's Safety Management System, crew training and advice, the securing of loose items on board, the placement of the life raft and a refit of the onboard rigging.

Among the several to give evidence was Australian Maritime Safety Authority navy architect Douglas Matchett, who provided insight into the possible causes of Cassandra's capsize.

Mr Matchett said based on the investigation into the capsize and the findings among the wreck, one of the possibilities was that a net on the starboard side became snagged in a hook-up.

According to the AMSA website, 'one of the most dangerous situations you can experience on a trawler is getting hooked-up'.

The court was told a hook-up can be anything a net can become caught on.

Mr Matchett said it was possible once Cassandra was caught in the hook-up, the vessel started to lean towards the side.

He described to the court a "righting turn", which is a vessel's way of compensating when pulled to one side.

Mr Matchett said it was possible Cassandra then turned to the portside.

He said sometimes the righting turn could be greater than the initial turn, causing a capsize.

Mr Matchett said it was also possible the capsize was caused

Previous evidence given by other witnesses at the inquest revealed that the trawler nets had been partly wound up at the time the vessel was discovered.

One of the nets was also partly torn.

Coroner David O'Connell said based on that evidence it could be concluded that the crew "tried to free" the net from the snag, causing the weight to shift to the portside, causing the vessel to capsize.

The inquest will continue today.