SeaRescue isn't an official craft - not yet, at least - it's an offshoot of SeaCraft, and consisted mainly of very good swimmers who were enormously concerned with the well-being of their fellows, and the well-being of their enemies.
Though every SeaCrafter could rescue a drowning swimmer, and was trained in basic healing techniques such as for poison thorns, hypothermia, and care for general sea-related infirmaties, the Rescuers took a more thorough course, which included, but was not limited to Rescue breathing, and a form of CPR, although "cardio pulmonary resuscitation" means nothing on present-day Pern.
SeaRescue has been seen as a hybrid between SeaCraft, HealerCraft, and perhaps HarperCraft, as people-skills are a must-have.
Many young SeaCrafters have made it their goal to become Rescuers, but few attain the high standards, set by the CraftMasters.
Return to Sennet Seahold.
Note: I am fully aware that SeaRescue does not exist on Anne McCaffrey's Pern. It is a "craft" that comes from my own imagination. My rationale: If lifeguards can come to be on Earth, then SeaRescue can come to be on Pern. It would've happened eventually, whether it made it into a book or not.