Just had the 2 best results and most terrifying flights every so far with one just kinda leaving me with questions. I was asked to launch off a 56ft boat 4 miles off the coast of the island. what i have learned. absolutely no wind if i ever attempt again the boat rocks to much fine on the landing but take off nearly ran in the the boats side rail. Was asked for a basic architecture shot put the heli up with no problem turned the gps on and the heli just started "freaking out" cant really explain what was going on aside from it not holding position and just moving violently in the air. Air speeds were 14knot with gusts 18-20 was flying no gps for about 1/2 the flight before it decided to work(position hold). I put it up again after landing and swapping batteries launched with the gps on no problem. Finally was filming a runner at the local stadium just a simple fly over durring their 100m sprint. the heli wouldn't hold position for the start was drifting a lot more than i am used to or comfortable with. and after one flight i turned the gps on and the heli just flew straight back past its home point (come home was not switched on) i had to again turn the gps off an fight to keep it in control same as the house flight earlier today. I am curious os soem thing wrong with the gps after the boat flight which was yesterday (the gps was slow that day for picking up the heli in flight but when it was on it held no problem. but today i am having soo many problems with it am under the suspicion that is it busted and needs to be replaced. its 12:51 just got in from the stadium ill post the logs for for all the flights i have mentioned because these situations are worrying luckily i was able to keep my calm and land the heli with out incident but if the problem can be solved help would be much appreciated.