Factual error: When the people of Lilliput find Gulliver's boat, he picks up his cell phone and says he doesn't have any signal but has 11 messages and proceeds to listen to them. If you have no signal at all, you wouldn't be able to check your voice mail.
Plot hole: How does Horatio (a Lilliputian) get to Glumdaclitch's dollhouse, which is on the second floor of the house? Jack Black is twelve time smaller than the Brobdingnagian, and the Lilliputians are twelve times smaller than him. How did he get up the stairs? Getting to the second story of the dollhouse would be challenging enough.
Revealing mistake: On Gulliver's MacBook when he is plagiarizing , he has the wrong program active at the top (Finder for Macists), when he is typing on the keyboard. He also doesn't have a single word-processing application open, which can be viewed at the bottom.
Deliberate mistake: When Gulliver is first placed in the dungeon, he is attacked by a tiny seagull, however comparing the size of the bird with Gulliver's foot, it appears to be about the size of a fully-grown Lilliputian. This was obviously done deliberately as a correctly-sized seagull would be far too small for the joke to be effective.
Deliberate mistake: At the beginning of the end credits, the newspaper article just repeats itself. Plus, it has a weird shift of going from a first person account to a third person review of the original book (including mentioning George I was King of England at the time of the writing of the Travels).
Continuity mistake: At the end, when Darcy and Gulliver are about to kiss before being interrupted, Darcy is holding the report in her right hand. When Dan walks in, the report is in her left hand.
Continuity mistake: When Gulliver visits Darcy at night her red Luxo changes positions between shots.
Continuity mistake: Dan tells Gulliver he's now his boss, then lowers his left arm. From the opposite angle it's raised and holding his bag's strap.
Continuity mistake: After Gulliver plays Guitar Hero he points at himself with his right thumb. From the angle from behind it's his left thumb.
Continuity mistake: When Gulliver is talking to Darcy, his lanyard goes from being blank to having words between shots.
Answer: Obviously, it's just a deliberate error in a fantasy film that is full of plot-holes and errors. They certainly aren't anchor lines, as the ships are actively involved in a military engagement (surrounding Gulliver). Also, no navy flotilla of sailing ships would have lines hanging loose at the bow or stern, particularly going into a military engagement. Rather, the lines would be coiled and neatly stowed on deck. In this case, the deliberate error permits Gulliver to tow away the Blefuscudian ships in just a matter of moments (even though Blefuscu is over a half-mile away by water).
Charles Austin Miller