Lake Michigan coast guard requirements.
day & night signals: Flares count for each, if disposable need 3+. Must not be expired
Sound making device: built-in horn, portable air-horn, etc.
PFD: 1 wearable for each passenger plus one throwable. Throwable must be out of compartments & easily reachable when under power.
Fire Extinguisher: 1 B-1 type - must be charged & not expired
Ventilation: Proper fuel area ventilation (typically already done by boat manufacturer)
Electrical: All batteries must have BOTH posts covered. A battery under a compartment, but with uncovered posts is NOT acceptable.
Other recommended, but not required, items: Enough fuel, anchor + rope, VHF radio, GPS, compass, first aid kit, common sense
Keep in mind all the above apply whenever you are on federal water even if only 20' off shore, not just out of sight from the shore.