Lots of ways, Anima, or Magus Siters can bomb it, as can decently built up characters.

Here is the recommendations assuming you haven't trained much.
1.Use Hastega, generally a Tidus move, before you can attack it this move comes in handy as it gives you a lot of turns.
2.Quick Hits again are very important, they get you a bunch more turns.
3.You get about 8 turns for each character, with the above moves that should be 11-12 with an extra hit or 3 for Tidus. Total of about 37 hits.
4.Bahamut's overdrive should do at least 20,000 (this is a low guess), spend a turn using this at the very end to finish it.
5.During your other 36 turns you need to deal 120,000 (maybe I should call it 28 turns or something cause for a lot you can't attack at the start.
6.28 turns to deal 120,000
7.Average of 4,285 per turn average needed.
8.Overdrives are useful, Wakka's Attack Reels should do 16,000+, Tidus's should do 8,000 (this is all assuming untrained characters, and assuming Tidus doesn't have blitz ace), Lulu should do maybe 8,000+.
9.Use 3 turns to do 3 overdrives and you might do about 24,000.
10.116,000 life left, 25 turns.
11.For the next 9 turns with Lulu double cast her best spell, for maybe 6,000 a turn. Wakka attacks for say 3,000. And if you have nothing better Rikku can toss gems for around 3,500.
12.12,500*9=112,500 Sin should have 116,000-112,500=4,500.
13.Last turn you can kill it easy but bomb it with Bahamut for 20,000.
14.Sin has -15,500 life left. This was all assuming you have untrained characters so you'll probably do better than this, for the last maybe 4 turns when it's close to the ship Tidus can come in for Rikku and use quick hit, this should add maybe 15,000 to the total damage here. Auron should be able to attack for more than Wakka so that could be another 10,000. At this point we're doing 40,000 more damage than Sin's life.