The following information is from The Maple Sugar Book by Helen and Scott Nearing. Sap was lugged by hand originally, from tree to boiling place. The next step in carrying sap was to let a team of horses or oxen do the work. On level ground a low-hung wagon or a sled was fitted up with a tub, and thus the sap was moved to the sugar house . But most sugar bushes are hilly.
Some sugar bushes are so steep, rough, and rocky that a wagon is a great disadvantage.
Therefore a sap sled was built. Sometimes it was a single bobsled, fitted with a tongue.