Method and apparatus in a system in connection with the spinnaker pole (8) or similar of a sailing boat, in which system a control line (12, 13) is attached to both guys (6, 7) of the sail (4). The control lines (12, 13) are arranged to run through the pole (8) and to move a piston (20) and the piston (20) is connected to means, with the aid of which the length of the pole (8) can be altered or the pole can be lowered to a lower position at its outer end. The piston (20) is preferably moved by the lines running around pulleys (23) and attached to the moving part (17) of the telescopic pole.