No, you should still charge them at 2.65A. Because the cells is in series, and each cell must not be charged any harder than 1C, unless otherwise is specified.
In series, all cells will have a current equally high as the main current in to the battery.
If you put packs in parallel however, then you can multiply the charge current as you did.

Those batteries seems ok for the suggested setup at first glance, not knowing more details about your prop, drive type or hull.
3s for a 3200Kv is a good place to start with for a smaller, high reving boat. Unless your propeller is ridicilously large, I think you will be within the safe limits for amp draw. The rule of thumb (for a little larger boats) is that the prop should spin at 30 000 rpm.
A 3200 Kv motor with a 3S battery will spin at approx 28000 rpm, under load, and 35000 at idle. So Ithink that thats a good place to start with.