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General Duties of the QMOW, Continued
Using All
It is important to use all methods available to fix the ship’s position.
Available Means The navigator is required by instruction to fix the ship’s position by all
to Determine
Position
available means. You as the QMOW must make every effort to
accomplish this. In actual situations, you will often use a combination
of methods to determine the ship’s position. If transiting along a
coastline and visual or radar fixes are available, use them! In the
following list you’ll find methods of fixing the ship’s position listed by
accuracy, from the most accurate to the least accurate:
A visual fix on three objects 120° apart
A visual fix on two objects 90° apart
An electronic fix by GPS in the encrypted mode
A visual bearing and radar range on one object
A radar fix using three range arcs on objects 120° apart
A radar fix using two range arcs on objects 90° apart
An electronic fix by the AN/SRN 12 SATNAV
An electronic fix by LORAN
Approaching
Land
When approaching land from the open ocean, the QMOW must start
checking to see if radar fixes can be obtained. At about 25 nm, the
shoreline will start to become distinct. If sharp points of the shoreline
are available, radar fixes should be obtained. Radar fixes are used in
addition to whatever means are currently in place. In other words, if
fixes were being determined by GPS, you would continue to plot GPS
and also plot radar. As the ship progresses toward land, visual fixes
would be added. This process continues until the ship enters restricted
waters and the navigation detail takes over the watch.
During all of this activity, you must continue to maintain the DR plot.
As you learned in chapter 8, the DR plot must never be neglected while
you perform other tasks. In obtaining a fix, you are actually updating
the DR plot. You’ll find that as a ship draws closer to land, changing
course often becomes necessary due to shipping traffic. This makes
keeping your DR plot up to date even tougher. On the open ocean, the
QMOW’s ability is not taxed often; however, the watch becomes very
busy when approaching land. Always make an effort to be prepared.
Make sure that you have the next chart available and that your books
and logs are up to date. If at any time, you are unsure of the ship’s
position, do not hesitate to contact your LPO or assistant navigator for
guidance.
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