6. Local rules and municipal regulations.
These rules deal with the distinctive lights required for different vessels, signals, speed, rules governing the management of sailing and steam vessels under different conditions of weather and various relative positions of vessels. While they have very often been the subject of judicial interpretation in collision cases their application belongs to the subject of navigation rather than to that of admiralty law in the present work.
The statutory rules are of the highest importance and the mere fact of a breach of any of these is prima facie (but not conclusive) evidence of negligence. The infringing vessel must satisfy the court that its violation of law not only did not, but could not, contribute to the collision.
As was said by Chief Justice Fuller in Belden v. Chase, 150 U. S. 674:
They are not mere prudential regulations, but binding enactments, obligatory from the time that the necessity for precaution begins, and continuing so long as the means and opportunity to avoid the danger remains. Obviously they must be rigorously enforced in order to attain the object for which they were framed, which could not be secured if the masters of vessels were permitted to indulge their discretion in respect of obeying or departing from them. Nevertheless, it is true that there may be extreme cases where departure from their requirements is rendered necessary to avoid impending peril, but only to the extent that such danger demands.
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Obedience to the rules is not a fault even if a different course would have prevented the collision, and the necessity must be clear and the emergency sudden and alarming before the act of disobedience can be excused. Masters are bound to obey the rules and entitled to rely on the assumption that they will be obeyed, and should not be encouraged to treat the exceptions as subjects of solicitude rather than the rules.
It is true that where obedience to the rules will result in collision a navigator is justified in disobeying the rule. It was held in the Oregon, 158 U. S. 186, "that the judgment of a competent sailor in extremis cannot be impugned." Cases in which disregard of the rules has been upheld as justifiable by the courts have generally been cases in which the other vessel has already infringed a rule and a situation has arisen in which obedience to the rule could only result in collision. Such exceptions, however, as was said in the Albert Dumois, 177 U. S. 240, "are admitted with reluctance on the part of the courts, only when the adherence to such rules must almost necessarily result in a collision—such, for instance, as a manifestly wrong maneuver on the part of an approaching vessel." In the John Buddle, 5 Notes of Cas. 387, it was said:
All rules are framed for the benefit of ships navigating the seas, and no doubt circumstances will arise in which it would be perfect folly to attempt to carry them into execution, however so wisely framed. It is, at the same time, of the greatest possible importance to adhere as closely as possible to established rules and never to allow a deviation from them unless the circumstances which are alleged to have rendered such deviation necessary are most distinctly approved and established; otherwise, vessels would always be in doubt and go wrong.