troubelshooting

I would like to make a new device for the want, where I can ajust the want rod - mine is fixed and I can´t change it ( see the foto) I heard from a German sailor that the hammering against the hull would stop if I twisted the want af few deg. but i can´t .
Before I make a new device I would like to know how big the distance should be from where it pivots to where the horisontal pusrod connects ( on this one it is 35 mm)