that is really hard to say given wind, sea, load including any water, temp. One would suggest that you take a windy day, loaded it with about 9/10 full load including yourself and put 1 gan in the fuel tamk and motor into the wind and waves. Have a hand held GPS with trip log and extra fuel. You will then know.
The other question is - how big of seas can a RIB take? Better than no boat.
What is the biggest seas that you have been in with your dinghy?
Me, about 3 feet in my 8 foot Portland Pudgy.