You’re not alone. A big thanks to BoatUS for helping to explain the difference and why they are important!
A “safety recall” involves a safety problem that relates to a boat or associated equipment that is less than 10 years old. The recall must pertain to a violation of federal safety regulations or “a defect that creates a substantial risk of personal injury to the public.”
A “Product Correction Bulletin” and “Service Advisory” generally involve the same thing: an issue that doesn’t pose an imminent threat to life and limb but can be dangerous. Repairs are generally at no cost to the boat owner.
To read more, and learn about other types of notices, see the complete article by BoatUS here: BoatUS: Recalls, Bulletins and Advisories Explained