on most boats today there is one verticle "pole", the mast. one horizontal "pole" the boom. on older boats like scows and optimists the diagonal pole is called the sprit. there can also be a spinnaker pole which you clip onto the mast to hold out the spinnaker on a run or a reech. on a asymmetric boat the spinnie pole is pulled out when the spinnie is raised, you cann't and shouldn't clip it onto the mast.