'Lo All, Both, the Borg Warner Velvet Drive and Twin Disc 502 manuals say that it is permissible to free wheel the shafts under certain conditions, which essentially limit the boat to hull speed. The Twin Disc manual is on the Celestial, but if I remember correctly, it adds that the engine should be started and oil pressure in the transmission brought up at least once every 24 hours. Take care and be safe. Wayne M/V Celestial Albin43 Sundeck