The squall is coming.
White squall "goofs"
Continuity
The underpants when Dr. Sheldon administers the shot.
The orange juice is not sloshing in the galley while rest of ship is pitching during the storm that sinks the ship.
When Gil is telling the story of his brother's death after his nightmare, his face alternates between being sweaty and dry between shots.
When Dean is thrown off the boat when the sails are up, there are no vomit stains on his shirt while he is in the water; however, the vomit stains return after he is back on deck.
In numerous scenes the sky changes from cloudy to blue in different shots.
About 5 minutes into the film when Charles Gieg (Scott Wolf) readies to board a bus, there are three Marines in the background. Between a short cut, two of them change position.
Crew or equipment visible
When Gil is forced to climb the sails, the wind blowshis shirt and you can see his wireless microphone pack on his back.
Errors in geography
At the beginning of the film their is an establishing shot of Charles Gieg's (Scott Wolf) house which we are told is in Connecticut. The trees are full of Spanish moss which typically is not found north of Virginia and has never been found north of Delaware.
Factual errors
During the sinking of the schooner the radio in the background is describing the final moments before the launching of Freedom 7, the spacecraft carrying Shepard - on May 5, 1961. However, the schooner sank three days previously on May 2, 1961, and the survivors were rescued on May 3.
In the scene when the boys are discussing the hearing Etham Embry's character says the ship went over because she was gybed. The term 'gybe' would never have been used on the 'Albatross' as you only gybe dinghies or yachts. On a square-rigger you would wear ship.
One of the Dutch schoolgirls are actual speaking Danish and not Dutch. In the role-list it shows that a lot of the actors are from Denmark. The languages are not even close to each other.
During the inquiry into the sinking one of the prosecutors tells the skipper the national weather service does not recognize white squalls.
The national weather service was not created until 1970, prior to that it was the US weather bureau.
Miscellaneous
When the Cubans have boarded the Albatross, they threaten to take Lapchick with them because he does not have his passport. As this is happening, Dean yells "if he's Cuban, Castro wears a dress", which doesn't match what he's actually mouthing. The scene was obviously dubbed, possibly for the MPAA or the director simply liked the other line better.
Anachronisms
According to the timelines shown on screen, the story starts in 1960 and ends in 1961. However, in one of the scenes on the ship, in the background you can hear JFK's speech about the Cuban Missile Crisis from October 1962.
In the scene where the Albatross comes across the Cuban Military Patrol Ship, electronics on the Cuban ship, most notably the Radar System, weren't available in the configuration seen in the early 1960s.
When the boat is in port to pick up the female students, there is a post-1960s vehicle driving on a nearby road.
At night in the lifeboat, the survivors see Alan Shepherd's Freedom 7 flight moving across the field of stars. Shepherd's lift-off was at 9:34am (Eastern Time) and lasted 15 minutes.
When the jitney first arrives at the Albatross to drop off the crew, a 1980 Pontiac Phoenix is in full view.
Q, no coincidences, right?