Just after 1am on October 13, Commander Ivan Ivanov and his crew received a mayday call.
A Malta-flagged ship, the Chelsea 3, was in distress and sinking in the Black Sea, 40 kilometres from the Bulgarian port of Varna.
The vessel had been hit by a drone that had blown an enormous hole in its side, and it was taking on water.
Within minutes, Commander Ivanov's crew were heading out to sea to try and reach it.
"The weather was extremely bad. The sea was stormy, with a very strong wind, and the visibility was very low," Commander Ivanov told the ABC.
The Black Sea has become a deadly theatre of battle as merchant ships carrying things like grain, chemicals and oil are increasingly caught in the crossfire of Russia's war in Ukraine.
Both countries have ports on the Black Sea and have been hitting ships going to and from each other's docks since Moscow's full-scale invasion began.
But in the last few months, the attacks have taken on a whole new dimension, and sailors have become collateral damage.
At least 38 have been killed since June, making the Black Sea the deadliest waterway in the world, even surpassing the Strait of Hormuz.
When the crew arrived, the Chelsea 3 was already listing to the left hard and the choppy…