You do not get a fine on the water, at the dock, at the ramp. You will only get a fine in court or if you plead guilty and you will THEN pay a fine.
A LEO can not fine you, they can only give you a summons. You will then appear in court or plead out.
As far as taking your gear, they will do that to hold as evidence. The LEO has no power to keep it permanently, only to hold for evidence. What eventually happend to the gear will also be decided by the court.