When Jake saddles the horse there is no saddle pad when he goes to the barn for the saddle. When he is shown saddling horse a saddle pad is magically on the back of the horse.
Although romantic, the laws about marriage at sea are governed by the ships registry. Based upon the accents and uniforms, the ship is British. For British ships, marriages by captains at sea are invalid and were banned in 1919.
Hank says that when he was in the white prison they read one Bible verse a day and that he was in long enough to hear the book read twice. Given there are 31102 verses in the Bible that means he'd have had to spend over 170 years in prison to hear it twice.
When Jacob mounts the horse to go for a ride, the shot pans to show the horse corral in the background. Included as part of that corral is a loading ramp, which is only ever used to load horses into the back of a truck so as to transport them somewhere. But they don't have a truck. In that era, the only way to transport horses somewhere is to literally make them walk.
Loading chute for trucks. The first loading chute was developed in 1946.
On the ship near Egypt Alex asks if there is no plumbing at the Yellowstone ranch. Spencer verifies wordlessly, yet on multiple occasions sinks and faucets are shown at the Yellowstone ranch home.