There's a tried-and-true method of raising spars (which has been in use for many centuries) called sheer legs. A bipod is created using two poles. These could be spinnaker poles, or a boom and spinnaker pole. The two sections are seized tightly together, and then spread at the base. The bases are then tied off (as in the bipod rig shown on page 557). The set of sheer legs are then used as a derrick to hoist the replacement spar.

In the replacement process, the base of the new spar must be securely tied at the base to keep it from kicking forward. Side shrouds are also rigged to keep the mast from wobbling side to side as it is raised.

Once the spar is set, the sheer legs are removed. They are then available for use as a main boom or mizzen mast.