The following terms and explanations are part of Penn State University's Naval ROTC Naval Science 302 course. Instructor LT David E. Fowler, USN has granted permission for its use on the Nitro Class AE web pages. If you are interested in viewing additional topics of Penn State University's Naval ROTC Naval Science courses, please visit their web site at the following URL: Naval Science 302: Navigation and Naval Operations II
Lifeguard station: If multiple ships are engaged in UNREP, a ship (usually the next customer) will be positioned approximately 1000 yards astern of the delivery and receiving ships. Man overboard is
a real danger during UNREP, so the function of the lifeguard ship is exactly as the name implies.
Waiting Station: After the previous customer is out of the way, we move up to the waiting station and this is where we begin the sequence of flaghoists and commence our approach.
UNREP course and speed: Generally dictated by the delivery ship if UNREP is a two ship event, or by the OTC for a group of ships. Usually chosen to provide the smoothest ride possible, unless it is vitally important that the force continue along a specific heading. Called ROMEO corpen and ROMEO speed.
Approach course and speed: Should be the same as ROMEO corpen with slightly higher speed, with minor adjustments as necessary to execute the approach. From the time we commence our approach until we are clear of the other ship after breakaway, DO NOT use rudder orders to maneuver the ship- only minor course changes are used. A key tool for use during the approach is the radian rule, which mathematically is
x (60/range) = angle off the bow (degrees)
And some good values to remember are, for a separation distance of 50
yards (150 feet):
1000 yards - 3 degrees
500 yards - 6 degrees
300 yards - 10 degrees
Once our bow is even with the other ship's stern, drop speed to ROMEO speed and glide into position. (of course, every ship is a little different and it takes a little experience to determine when to drop the speed).
Shot Line: The first thing to come across. After this comes the messenger, and the phone and distance line, which is used for sound powered phone communications between the two ships and for gauging distance. The line has a flag every twenty feet, and they are color coded in the sequence green-red-yellow-blue-white-green (I remember it as "Go rub your belly with grease"). This line is kept taut by linehandlers.
Tensioning the span-wire: The bridge of both ships must be alerted before this happens. This is a very important piece of information for the helmsman and the conning officer, since the force exerted by the tensioned span wire will tend to pull the two ships together, and the helmsman will have to compensate with the rudder to maintain the ship on ROMEO corpen.
Engage the rig: The choice of rig depends on the item to be transferred, be it food, fuel, ammunition, other cargo, or personnel.
Transfer supplies and/or fuel: Throughout this evolution, the conning officer must pay careful attention to the separation between the two ships. The delivery ship will maintain course and speed, and the conning officer on the receiving ship will make minor course corrections (half a degree at a time!) and speed changes to maintain position. An extremely competent helmsman is essential to success.
De-Tension the span-wire: Again, the helmsman and conning officer need to know this is happening.
"All Lines are Clear:" Once we know this, we increase our speed (but don't change course just yet!) and once our stern is clear of the delivery ship's bow we put the rudder over (if desired) and head on our way.
Breakaway/Emergency Breakaway: These are the same thing, except the emergency breakaway is done FASTER. We DO NOT cut lines or anything of that sort. (no axes are required for this evolution). Typically, we always end UNREP with an emergency breakaway for practice.