More than 3 so you can pick but I send this out to all crew in advance in addition to asking health questions in advance...and then safety breifing on boat before departure, this months Boat US magazine has an article on this. I take a lot of college kids out hence the social media point

Captains Briefing (SLOW IS PRO)
1) Life Jackets-where are they? Life Boat. Tie a life jacket to back railing
2) Emergency equipment-VHF (Channel 16) flares, fire extinguishers. VISAR is rescue team.
3) Man Overboard Drill-Shout, Throw & Point. Don’t take you eyes of the person in the water. CONSTANT EYE CONTACT. Throw the life ring in and the life jacket in.
4) Always count heads…can you count to “10” or however many people we have on board
5) Securing safety railings at all times…holding yourself in back.
6) One hand for you one for the boat (3 points of contact at ALL times)…when we moor or dock or leave mooring if you aren’t doing anything for the boat stay seated and if it doesn’t involve the boat or boat safety don’t talk to me. Use hand rails at all times. Don’t carry something onto the boat or dinghy. 1st person cross and then hand gear.
7) Tank water is for bathing ONLY
8) Head (toilet) operation & red-light location…if it doesn’t come out of you it doesn’t go down the toilet
9) Stay hydrated-if you aren’t peeing you aren’t drinking enough
10) No night swimming-Rule of 3 wherever you go. Use noodles when open snorkeling for visability
11) Mooring-3 people up front. 1 on port line and 1 on starboard and one in middle with boat hook. Lines need go under rail and through eyehook and then brought back and tied. Manning the boat hook to pick up the mooring painter eye hook. Communicate with captain. DO NOT GET BETWEEN BOAT and anything HARD...no human fenders.
12) Docking-people on lines and people on fenders. Hold fender line at right height. Don’t use your body or any other part between boat and dock. Don’t push off the dock hard and fast and don’t pull a rope hard and fast. If I need you to snug a line wrap around cleat once and hold. Simple Cleat hitch knot….
13) Fire-Get everyone up and out.
14) Gas line – Light and breaker. If gas on one person must stay with oven/burner.
15) Everyone is a lookout for boats and anything else
16) Dinghy-stay on sides and not in front. Shift lever. One person hold dinghy rope (painter) tight while others boarding. Dinghy needs to be tied down on elevator. Dinghy kill switch. Dinghy tilt engine. Colored bags on dinghy
17) If you stay below while moving and you get seasick you will be a boating buzzkill. Stay ahead of any potential seasickness
18) Get enough sleep…if you need eyemask bring it. No ear plugs
19) Social media-be smart about being dumb. It is forever. Switch off data on phone
20) Questions…ask ask ask…don’t be shy and don’t wait. If there is something I should know let me know….if you need something let me know.