To dream of oars represents your ability to persevere or get through an uncertain situation. An oar may reflect you having to do something the hard way to get through a negative situation. Slowly dealing with a problem at all.
To dream of losing oars may symbolize situations where you feel totally cut off or unable to do anything about your problems. You may feel stuck or stranded with uncertainty. Feeling that there is no way out or that escaping problems will be a very long process.