NAVIGATION RULES AND VESSEL DRAFT

Well, nobody said the Navigation Rules were easy to remember.  That’s why it is important to familiarize yourself with the Rules and keep a copy onboard.  Sometimes, through a combination of hazy memory, misconceptions or just plain misinformation, we end up “remembering” Nav Rules that actually don’t exist.

One such imaginary Rule goes something like this: “deep draft vessels have the right-of-way over shallow draft vessels.”  That misconception goes on further to assert that “offshore in the ocean, there is no ‘deep draft’ preference since the ocean is deep enough for everyone.”  Sorry, wrong on all counts!

The fact is, the Navigation Rules provide for “deep draft” vessels in two areas.  Rule 18 specifies the “responsibilities between vessels.”  It prescribes a “pecking order” of priority, based on the various types of vessels and their activities.  With very few exceptions, it states that all vessels “shall avoid impeding the safe passage of a vessel constrained by her draft.”               

You may be surprised that Rule 18 only applies to vessels operating under International Rules.  That’s right, not Inland, but offshore in the ocean, where most people think there is “enough deep water for everyone.”  An example of a “vessel constrained by her draft” under the Rules is a “super tanker” which can have a draft in excess of seventy feet.

As deep draft vessels approach entrances to ports around the world, they are still operating under International Rules, and are confined to areas deep enough for their draft.  Quite simply, they stay in the deep water out of necessity.  In such cases, shallower draft vessels (30’, 40’, etc.) must keep out of the way of vessels constrained by their draft.

There is no such “general” provision under the Inland Rules.  In inland waters, ALL vessels are eventually constrained by their draft.  As a towing and salvage captain, I have pulled such vessels off the beach, out of a marsh or off a shoal.  The Inland Rules do not address draft constraints in the same “general” way as the International Rules.  To do so would require hundreds of rules, given the varied depths and situations in inland waters.

Where the Inland Rules do address the draft issue is in “narrow channel” situations.  Inland Rule 9 states that “a vessel of less than 20 meters (+/- 65’) in length or a sailing vessel, shall not impede the passage of any vessel that can only navigate within a narrow channel or fairway.”  A “fairway” is generally meant to be the area of the “buoyed” channel, plus the area of the adjacent waters that are navigable by all but the deeper draft vessels.

What Rule 9 amounts to is that smaller vessels (under +/- 65’) and sailing vessels, neither of which have the draft constraints of large commercial vessels, must “give way” to vessels confined to the channel or fairway.   The Rules for “open water” concentrate more on the type of vessel and its activity, while the “narrow channel” Rule focuses on a vessel’s inability to leave the channel without going aground.    The provisions of Rule 9 also apply under the International Rules.

The next time you are discussing the Nav Rules with anyone, pick up a Rules book and make sure you have the facts. It is easy to do!

Until next time, I wish you clear skies, fair winds, and calm seas!