Final answer:
The first safety precaution for boating in stormy weather is ensuring everyone on board is wearing USCG-approved Personal Flotation Devices.
Step-by-step explanation:
The safety precaution that should be taken first by a boat operator when boating in stormy weather is to make sure all aboard are wearing USCG-approved PFDs (Personal Flotation Devices). In stormy conditions, the risk of capsizing or passengers falling overboard is increased, and having PFDs on can be critical for survival.
Once everyone is wearing a PFD, additional steps such as closing hatches to prevent swamping and broadcasting a 'MAYDAY' if necessary, can be taken. It's also essential for boat operators to be aware of weather conditions before departing and to avoid boating in storms if possible.