From USRowing: Due to the change in construction of many oars from fixed to adjustable handles, the USRowing Safety Committee is no longer recommending using oars as an emergency flotation device. The USRowing Safety Video has been edited to remove all mention or depiction of oars being used in a water rescue, and we are removing it from all of our publications. Please be cognizant of this when showing the old version of the safety video, and if you have a USRowing safety poster in your boathouse, please cross out the word 'oar' as a flotation device under the 'Rowers and Coxswains' section.
The fixed handles were, typically, glued into the shaft and would hold air. The adjustable handles are not airtight because of the potential opening where the handle and the shaft meet. The oars made from carbon fiber will eventually sink if all of the air has escaped from the shaft.
If you are using fixed handle or wood oars, USRowing would like to emphasize that an oar is not considered a flotation device such as a Personal Flotation Device (PFD), only an emergency flotation device, like a seat cushion. All launches should have PFD's for everyone under the coaches' supervision and for the occupants of the launch. USRowing also strongly recommends that coaches wear a PFD when operating a coaching launch.