You don't say, but I'm assuming your cruising plans in a 30ft boat are coastal and maybe working up to a 3 day offshore passages.
I expect this will anger some, but Jibes list is absolutely right for 1985 (when I had a Sabre 30). It's not the list I'd choose for someone getting started today.
Bell (not required on less than 65ft and generally useless since you can't hear a bell from more than 100 feet over engine noise)
Horn (required and better than a bell - but still hard to hear over engine noise from any distance.)
Paper chart navigation is dangerously inaccurate and error prone compared to GPS with an up to date electronic chart. "Dead" reckoning is well named. When I started cruising in 1979 in Maine fogs, I had to do this stuff but judging leeway and current set was mostly guess. Math errors were common. If your regular chartplotter dies have a spare electronic system or
two (Ipad or smartphone with waterproof cover). Put a chart program on your wife's phone too. And remember with any electronic chart, you MUST zoom in to check that your course doesn't cross some hazard that isn't displayed when zoomed out.
VHF Radio - yes but carry a couple of spare handhelds.
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I prioritize safety based on my level of worry:
Man overboard - Should be everyone's biggest fear. My rules: Out of harbor, no one leaves the cockpit without a lifejacket. At night, you also must wear a safety tether if leaving the cockpit. Carry a Lifesling and both you and your wife practice in normal seas. First time guests are shown how to use the "Man overboard" button on the chartplotter.
Dead battery - the most frequent serious problem. With no battery, very little on the boat will work. Have two batteries and only set to "Both" in an emergency. I also have a spare 3rd battery under a berth with a set of car jumper cables sealed in plastic. It's a Group 27 AGM that only needs a top up charge once a year. Even if you never use this for yourself, I assure you that you will take it in the dinghy to rescue others.
Collision avoidance: A collision with a commercial ship is the next biggest worry. Install an AIS transponder. The smaller you are (e.g. 30ft) the harder it is for a large ship to see you on radar or by eye and your slower speed makes it harder for you to get out of the way. Carry a really big flashlight that will scare a bored bridge watch. I like this one:
http://store.marinebeam.com/marinebeam-ultra-long-range-cree-rlt-illuminator/
Fire: Fire extinguishers, stove fireblanket, propane solonoid. Correct fuse/breaker and wire size for every circuit including engine start. Tighten every connection holding a battery cable big enough to make a fire starting spark (that's most connections).
Sinking: Emergency big bilge pump (2000 GPH but 3800GPH is better) with 1 1/8" or larger hose. Mount higher than normal bilge pump so it stays dry most of the time. Clean bilge to avoid clogged strainer. Leak control plug ("Stay Afloat" is my favorite). ABYC approved seacocks and double hose clamps. Below waterline hose replaced every 10 years.
Distress signalling: VHF radio, cell phone. If going more than 5 miles offshore an EPIRB or PLB or Delorme Inreach (if you can only have one, I'd get the Inreach but you have to keep it charged)
Engine Failure: Set of tools. Six spare fuel filters. Keep fuel tank clean (add microbicide at every fuel fill up). Have spare raw water impeller and gasket. Know how to install it. Wide silicone tape for hose repair.
Steering failure: Emergency steering plan (not feasible on some boats)
Anchor drag: 2nd anchor and rode that can be deployed in 5 minutes. Extra rode: Oversize (5/8" or 3/4" for 30ft) long (300ft) piece of extra line that can also be used as tow rope or extra rode.
Rig: Nipper pliers to cut cotter pins plus punch and hand sledge to drive out turnbuckle pins if dismasted, hacksaw with many spare blades. Sharp knives some serrated (and always carry a knife when on a boat). Spare shackles, spare low stretch rope as long as halyard (can be used as halyard, genoa sheet, or stay), stainless wire, 1/8" amsteel rope or similiar, sail repair tape, needles, waxed whipping twine and sail thread.
Dingy: Unless you are in mid ocean, help will respond to your distress call within a few hours. You don't need to survive in a liferaft for a month. A standard inflatable dinghy will keep you afloat. (help reached the Titanic just a few hours after sinking).
Of course this list is very personal. Part of the fun of outfitting a boat is learning what people choose and then deciding if you agree.
Fair winds
Carl