Goofs

At 25:50 we see the sunset just to the right of Queen Mary's wake. Poirot and Hastings are at that time sailing toward America while accompanying the young banker and the £ 1 million bond box. Sunsets usually take place in the west, so the ship must be heading the opposite way, from America to Europe, during the 13-second shot of the wake and the sunset.

Hastings describes the Queen Mary as "weighing" 80,000 tons. Tonnage in ships is a measure of enclosed volume, not weight.

A ship that is underway does not have the slow rolling motion shown.

When Mr Shaw drops his cup you see it break twice. However, it is also shown in slow motion, indicating this is a stylistic decision not intended to be taken literally.

The liberty bonds with the $50 denomination and an image of Thomas Jefferson were square in shape, not oblong as shown in the film. Also it would take 20,000 bonds as shown to make up the $1 million; the case is clearly not big enough to hold that much paper.

Upon Poirot's return to England on board the Queen Mary, there is a brief shot of Southampton docks. To the right of the terminal and behind, are many cars and vehicles that are obviously from the 60's or 70's, not from the 1930's when this series is placed.