Hi Colin.
You use the term “Rudder Slack” and it is associated with the “Survey” you have completed.
Piecing this together, could the survey be referring to rudder slop?
It is a term that refers to the time it takes for the rudder to actually move from the time that you initiate a rudder control movement. This often occurs with rudders controlled by a wheel in the cockpit. The cable or chain that transfers wheel movement to the rudder is “slack”. This translates to sloppy rudder control. Your fix is to inspect the control system and make adjustments to the cables as necessary. Also check that there is no damage to the control fixtures (the quadrant and blocks used to support the cables. They should all be sound (solidly affixed to the boat).
There is another possibility. You may want to have the surveyor clearly identify what he means by the language used. This second possibility could be that the rudder post bearings are worn, or that the internal structure of the rudder is compromised and the rudder post is loose inside the rudder shell.
These latter two possibilities are of greater concern and are also less likely.