Question: In [Triangle](http://www.imdb.com/title/tt1187064/), at the start when Jess arrives at the boat for the "first" time, is this the start of the continuation of the ending scene?

It's known that the cruise ship and any surroundings after leaving it is in a time loop.

Though Jess remembers the ship and tells Greg, she makes no indication that she is in the time loop. So yes, the movie was meant to confuse the user. But seeing that, according to the number of dead Sallys on board, the time loop occurs more than 20 times.

So, the first time she entered the loop, the storm sent her into an alternate reality with the never-ending time loop? Is this what the movie was showing? I noticed there is a deadly Jess that was not really in the foreground that got shot in the head, and stabs Sally and Downey in one of the rooms. I cannot really place where she falls into the picture seeing that one of the previous Jess instances killed that Jess instead of letting her jump overboard.

So is there a separate timeline/reality?

Answer: 
Not the way I remember it. The way I see it Jess is in a kind of purgatory, as the end of the movie shows her as an abusive mother. She's trapped in the time loop, but seems to be gradually changing things. Perhaps when she has righted all her wrongs she can be free?
This is the first time I've seen Triangle so my answer may have flaws in it please correct me if I am wrong, here is my understanding of what has happened:

The abusive mother Jess was killed before the beginning of the film by a Jess that emerged from the future to protect her son from her rage. The future Jess tries to move away from the crime scene with her son but this results in the death of her son. She remembers there is a certain loop on a certain ship that can take her back to the time before her son's death. So she takes a taki to the harbour but by the time she reaches the harbour she loses her memory because of her trauma. She arrives at the harbour to meet her friends and sail with them, the boat gets flipped over by a storm , and an abandoned ship arrives on a collision course with the boat. Jess from a few hours before the amnesia is on the ship and she watches as they board. She have seen them die by a masked figure (not aware that the figure is her future self also before amnesia). She tries changing the course of events by stopping vetor from strangling her and by shooting the masked figure before he will kill her friends. But the result of this is an alternate course of actions happening concurrently with the results of the original course. The altered course alter the original events and the altered events restore the original course (Jess tries to change her past causing alternate future for Jess with the alternate Jess trying to change her past resulting in the original future of Jess). Either way, she believes that the loop repeats when everyone dies (although I believe it happens as a reaction to the time shock caused by Jess knocking her future self out / or killing her, and it is the time loop that causes this time shock), so Jess wears a mask and tries to kill everyone on board so that - as she thinks- the loop should repeat. She does kill everyone but fails to kill herself, getting knocked out or killed and falls into the sea, the Jess that falls - dead or alive- experiences both time shocks. Resulting in her returning to earlier this morning where she becomes the Jess that emerged from the future to kill the abusive mother Jess trying to protect her son.

So the abusive mother Jess is dead before the beginning of the film and never contributes in its events, and all the Jesses seen throughout the films are paradoxes without beginning or end with each one of them becoming or resulting into the other, an endless loop that she keeps trying to escape, but it is her attempts to escape that create an alternate loop which creates the original loop, all what is certain that both loops happened and that Jess is in torment, maybe its her destiny or its a punishment for nearly killing her son or whatever, and each time she gets a chance to break the loop represented by the taki driver but it is known that she will always waste it.