[when i go on the water with the k-drive my pc crashes]

(first off sorry for the bad english) 

so like the title says when i go on the water with the k-drive in fortuna my pc crashes and i have to restart the pc. if i dont go in the water everything is fine but the moment i do my pc freezes.

i only experiens it when i enter the water. all normal missions are fine. it is making fortuna almost unplayeble.

any help would be appreciated

 

if needed these are my specs

GTX 970

i7 4790

32gb ram