Hi Geoff,
I read with interest your comments on the difficulty of removing o/b for racing, on Parker 21s. My Parker 21, this is now my 3rd season, came with a fairly new Tohatsu 6hp, 4 stroke. This clamps on the original aft facing mounting plate with ease and it is possible to lift it out of the well, the prop just goes through the cut-out. However, for racing I decided that I didn't want all this weight on board at all, particularly at the stern! My solution was to fit a fairly small pivoting o/b mounting bracket to the transom, sufficiently far away (on the port side) so that it does not foul the rudder. On race night nights, my 6hp Tohatsu is ashore. I then use the 2.3 hp o/b off my tender to motor on and off the mooring whilst the sails are raised. During the race, the bracket pivots upwards so that the o/b is completely clear of the water. This also has the advantage that when we are cruising I effectively have two engines ready for action, if one fails to start. If you're interested I can send photos of the arrangement. The hardest part was having the courage to drill the first hole in the transom to mount the o/b/ bracket!
Best regards,
Peter