RedactedNarrative: Two paddle boarders were out on SUPs when one individual fell overboard.  The other attempted to rescue him putting himself into difficulty.  A nearby boat pulled one individual out of the water who required no medical treatment but failed to locate the second after he slipped under the water.  The second victim was quickly located in 8-10 feet of water.  Attempts to resuscitate failed.  PFDs were attached to each SUP and were worn.