Maybe sabotage with something like this?: https://www.vice.com/en/article/xgy4q7/mysterious-sea-drone-surfaces-in-crimea https://www.vice.com/en/article/xgy4q7/

Maybe sabotage with something like this?: https://www.vice.com/en/article/xgy4q7/mysterious-sea-drone-surfaces-in-crimea https://www.vice.com/en/article/xgy4q7/mysterious-sea-drone-...