Final Countdown is the story of a precocious collie that is separated from her owner for a time following a boating accident.
I heard people talking about this before I saw it, and I was kind of disappointed, just because I had misunderstood or got an exaggerated recollection or something, and was just plain expecting some events that never happen through the whole movie, and it tainted my viewing, even if unfairly.
It is a fairly interesting premise, and it does borrow slightly from a conspiracy theory that was floating around at the time. I will admit, it takes a while to get to the "meat" of the movie, and in reflection, the Martin Sheen character was unnecessary to the progression of events and generally didn't make a lot of sense when you think about it.
There is also the issue that they seem to spend some time in the beginning; pretty much the first half of the movie showing normal business as usual on an aircraft carrier, and it really seemed to drag leading up to the payoff.
The "payoff" is: this aircraft carrier finds a wormhole that sends them back in time to just prior to the Pearl Harbor attack, and after some extensive debating and figuring out that is indeed what happened, the movie perks up a bit. To its credit, accepting they time traveled would be a more gradual process since, the ship is at sea without any landmarks or instant tells of their situation. That part is handled well, but the beginning prior to that was so loooooong I was already anxious for them to get on with it.
From here on, there is less to complain about, the movie is doing the thing you expected it to do and stuff is happening. They end up shooting down a couple of Japanese planes that were scouts for the Pearl harbor attack, which they make a point of saying was super easy because they had a 40-year technological advantage, and they end up taking in a lady, an old man, and a dog that they rescued from their boat being sunk, and one of the Japanese pilots who survived. The captured pilot gets crazy and somehow gets a gun and kills a bunch of people, which was a surprise.
What they almost end up doing is, the ship captain ends up basically saying "fuck it" and they are fixing to take on the entire Japanese invasion fleet and fuck up the course of history seven ways from Sunday, just because they got a future boat and it would be awesome to just pown the shit out of them; which is what I THOUGHT was going to happen, but the time wormhole calls them back before they can get to it, and it wasn't meant to be or whatever, and it turns out since almost no one saw them and they ended up doing almost nothing, the normal timeline always had an unnoted future boat in it all along and everything played out as it was meant to be. Disappointing since I was genuinely expecting them to create an alternate timeline by eventually destroying 1940s Japan by use of a future boat.