Some upcoming events that come to mind:
- IROS 2018 - Madrid
- ROSCon 2018 - Madrid (?) - I think it is not confirmed yet
- Breaking the Surface - Biograd na Moru, Croatia
- Maritime RobotX - Hawaii, US
I don’t know how it could work to organize something like a workshop alongside any of these events (I think in Breaking the Surface it can be still proposed to organize a workshop session), if there is an interest from more people an workshop, it could still be done. All these events will happen from October to December of 2018.