Su Xunxian can help out with the sharks, but especially if he doesn't have something to feed them as distraction, it'll still be advisable that they row past them in a more expedient way.

Beyond that, he'll be doing his best to charm the crew (and yes that may well go well towards flirting if there are those who are susceptible) which he will later use to try and ease things until Jim is done with the negotiations, hopefully.