Apwc must be operated in a reasonable and prudent manner. it is illegal to:
a) weave your pwc through congested waterway traffic.
b) swerve at the last possible moment in order to avoid collision (as in spraying another person or vessel, or playing "chicken").
c) jump the wake of another vessel unreasonably or unnecessarily close to that vessel or when visibility is obstructed.

A PWC must be operated in a reasonable and prudent manner. It is illegal to all the three mentioned points.

Explanation:

Weaving a PWC through congested waterway traffic may lead to fatal accidents due to narrow water path ways or some kind of obstruction. One must look for the clear waterway traffic to weave.

One should not operate in a manner that requires swerving at the last possible moment to avoid collision as doing so, again, may result in fatal accidents. It is always better for the operator to play safe while weaving a PWC as there is a very low chance of survival if, unfortunately, one meets with water accidents.

Again, it is never a good idea to jump the wake of another vessel unreasonably or unnecessarily close to that vessel or when visibility is obstructed as the visibility might be just an illusion which may result in unknowingly welcomed fatal accidents.  

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answer; no longer than a reasonable period of time;