Greyhound is a 2020 American war film directed by Aaron Schneider and starring Tom Hanks, who also wrote the screenplay.

In February 1942, Allied convoy HX-25, consisting of 37 merchant and troop ships en route for Liverpool, enters the "Black Pit", the Mid-Atlantic gap, where they will be out of range of protective air cover.

Three days into the "Black Pit", high-frequency direction finding intercepts a German transmission and Greyhound identifies a U-boat heading towards the convoy.

That evening, the 'grey wolf' U-boat torpedoes an oil tanker and escapes Greyhound by using an underwater decoy device called a pillenwerfer, "pill-thrower", so that depth charges are wasted.

Dicky receives minor damage due to the close range, and Greyhound is hit on its port side by the U-boat's deck gun.

Although worried about compromising the remaining defenders, Krause chooses to break radio silence; he orders transmission of a single word "help" to the Admiralty.

A Catalina deployed by British RAF Coastal Command arrives and Greyhound fires to mark the location of the second U-boat, allowing the flying boat to drop its depth charges and sink it.

In the film, this aspect is omitted and instead an inclusion of a scene is added where Krause proposes to Evelyn to come with him to a beach, though he accepts her hesitant refusal as the war is going on.

Producers took numerous 3D scans of the restored ship's exterior at Halifax, Nova Scotia to create the CGI version of the corvette.

The website's critics consensus reads: "Greyhound's characters aren't as robust as its action sequences, but this fast-paced World War II thriller benefits from its efficiently economical approach.

[23] Writing for the Chicago Tribune, Michael Phillips gave the film three out of four and said: "Like the canine, [Greyhound is] trim, narrow of scope, and it runs efficiently and well despite a barrage of on-screen time stamps and vessel identification markers".

[24] David Ehrlich of IndieWire gave the film a "C−" and wrote: "A terse and streamlined dad movie that's shorter than a Sunday afternoon nap and just as exciting, Greyhound bobs across the screen like a nuanced character study that's been entombed in a 2,000-ton iron casket and set adrift over the Atlantic.

The film offers a handful of brief hints at the tortured hero who Forester invented for his book ... but the whole thing is far too preoccupied with staying afloat to profile the guy at the helm in any meaningful way.