When rotating hard-to-turn shafts by means of straps, pipe wrenches, chain hoists, or any other means, you could be deflecting the shaft. This can cause significant alignment and repeatability problems to occur, making the task of collecting accurate alignment readings almost impossible. The problem is easy to overcome, though. Simply switch your ROTALIGN ULTRA to Multipoint or Static measurement mode instead of using Continuous Sweep mode. Your readings will be taken while the shafts are stationary and with no external forces applied.
Between the two measurement modes, multipoint will be the measurement mode of choice. The jerky, starting/stopping motion you will most likely be experiencing will make it very difficult to stop at the specific angles needed for static mode.