Safety comes before racing. These obligations apply to boats, competitors and support persons alike.
1.1 Helping Those in Danger
If a person or vessel is in danger you give all the help you can, whatever it does to your race. You will not be penalized for anything you do to help, any means of propulsion may be used to do it (rule 42.3(g)), and you may ask for redress for the places you lost (rule 61.4).
1.2 Life-Saving Equipment and Personal Flotation Devices
Carry life-saving equipment adequate for everyone on board, with one item ready for immediate use, unless class rules provide otherwise. Each competitor decides whether a flotation device is needed for the conditions and is responsible for wearing one. When the race committee requires PFDs, that is rule rule 40.
Common situations
Capsized boat near you on a run
If a sailor is in the water and not managing, stop and help. Sort out the score afterwards: rule A9 gives the committee ways to give you a fair result.