What is the problem with the Tsimtsum that causes it to sink

We can infer the ship sank due to a problem with the engines, which resulted in an explosion.

Something was wrong with the engines, he said. Did something go wrong with the fixing of them? I don't know. I don't think anyone will ever know. The answer is a mystery lying at the bottom of thousands of feet of water.

I think there was an explosion. But I can't be sure. It happened while I was sleeping. It woke me up. The ship was no luxury liner.