I remember someone collecting his new cat, taking the wrong turn, doing a U turn and catching his mast on a telagraph pole, snapping it (the mast not the pole - naturally.)

Something that hasn't been mentioned is, if the mast sits on the aft beam, not on a support, it needs to be very carefully padded between the beam and the mast. Because of the movement of the forward support and the flexability of the trailer, especially on bumpy roads, quite thick padding (carpet)can wear away very quickly, damaging both mast and beam.