The keel of a modern sailboat does provide "righting moment" to help keep the boat upright, but it's also used to provide hydrodynamic lift in opposition to the sails so that the boat can sail somewhat upwind. These two goals have to be balanced against each other and against performance in the context of mass and friction.
I suppose though a drone has more flexibility in design parameters by not having people and people-related supplies on board.
As long as it not fills with water, I'd say it will right it self.
On a traditional boat the sails can dig down in the water and needs to be released rather quickly, and you don't want the hatch to be open, but neither of this seems to be a problem here.
Theoretically, a sailing sensor drone could even be constructed as a submarine, sailing on the surface in regular conditions but able to dive into the currents if conditions get too harsh. It would not be able to maneuver or communicate while submerged, but it could resurface on a timer, or use sensor data to identify to make an educated guess. (This could also qualify as a piracy countermeasure, should the drones get targeted for parts)
I would think this would be a perfect application of a deep, full keel (which offers the maximum stability and self-correction, but in a manned sailboat tends to be too deep to bring into certain places which is why so many sailboats don't have full keels.)
That said, I don't know much about sailing other than it being on my bucket list of things to learn so I've been reading up on it, and I've been actively searching for a good simulator that works on gnu/linux... (anyone know of one?)
I suppose though a drone has more flexibility in design parameters by not having people and people-related supplies on board.