Ships crossing the strait expected a moderate ebb tide but didn't experience it. The tide condition was very unusual.

The steamer ‘Wakanui’ had a severe buffeting and was delayed for Wellington by a squally southerly. When they passed Cape Terawhiti at 4:00am on the 13th there was an abnormal current running.

When the 'Patena' left for Nelson from Wellington at 6pm on the 12th, weather was thick with a moderate southerly gale and the land was wholly obscured.

The steamer 'Blenheim' and the 'Opawa' were carried many miles northward on the ngiht of the 12th by an extraordinary current.

Steamer SS Penguin was bound from Picton to Wellington and struck abreast of the outfall of the Karori Stream, on what was believed to be Thoms Rock, close to Cape Terawhiti. It occurred at 9:45pm on the 12th and tore a hole in the hull of the ship.

There were 105 persons on board (64 passengers and a crew of 41).

As the steamer had entered Cook Strait at 7:50pm the weather was fairly clear but halfway across the straits it became very thick. It became a wild and stormy night resulting in poor visibility and one could not see very far out to sea. There was a strong southerly wind and a heavy dangerous sea running.

The steamer sank at 10:52pm on the 12th. There were 75 casualties including 17 woman and 14 children.

One of the boats with women and children in it was smashed against the side of the ship and the people thrown into sea. Shortly after that the second boat was lowered down and it capsized. The lifeboats had a rough time in the swirling, treacherous sea. One of the rafts was completely overturned three times during the wild and stormy night, the other was overturned four times.

At the scene of the wreck, at daylight on the 13th, the weather was so thick that one could not see far out to sea. The sea was running very high, there was heavy southerly weather and the weather was very cloudy and misty.

The Court of Inquiry into the loss of the Penguin found that the cause of the casualty was the presence of an exceptionally strong flood tide, coupled with the breach of Article 16 of the Regulations for Preventing Collisions at Sea by the master of the vessel, and with his failure under the existing circumstances to put to sea when he had run a course of 18 miles. The casualty was contributed to by the default of the master in not putting his vessel's head to sea sooner.