It was a bad day for the engineers on the John 1 yesterday.
It is a tough slog going through the Gulf of St Lawrence in a spring of heavy ice conditions if you don't know how to manage the engineroom in ice conditions or the SW system is not designed for recirculating to the seabay.
The Gulf is particularly bad because the ice carries a lot of snow or is slushy which makes for headaches when it gets in the seabay.
The vents get plugged if they aren't kept shovelled clear on deck, the seabay pumps slush out on deck with the air and it freezes eventually blocking the vent. The seabay slowly fills with air, then the SW pumps get airlocked and down goes the plant. Or, if the engineers allow the seabay temperatures to drop which is the kiss of death, you have to keep the seabay temperatures at 22-25*C to keep it clear of slush. Once they get plugged and the strainers are full the only way to clear it is to shut the valves, open up the strainer and shovel it out into the bilges. I have been told there was a lot of water in the ER so that is one possibility.
Until the TSB releases their report or other info comes out, it will not be known for sure what has happened.
But here is the ice chart for today and there is certainly a lot of ice out there: