(We aren't simply checking boxes!)
(One can't properly critique the job unless they have performed the job.)
Squat, do we really understand squat? It is doubtful one size fits all! What I’m referring to is ship squat calculations being applied to ATBs along with conventionally connected notch tugs and barges. During the 2014 Annual Tug & Barge Forum held at SUNY Maritime, I proposed a challenge to Marine Architects, Engineering Firms along with Faculty and Industry Experts in attendance to address this issue.
Obviously Bernoulli’s Principle is in play even with tugs and barges. However, the reactionary effects on the components are not the same as that applied to a ship due to the articulating or hinge action of the tug whether an ATB coupling system or conventional connection composed of wire rope or cordage creating the connection.
Those experienced with ATBs and large notch and deep notch units will acknowledge that the tug is most affected under squat conditions. When transiting with limited UKC (Under Keel Clearance) the stern of tugs are known to actually submerge making their aft deck become awash. Now the wildcard, the forward portion of the tug is connected or making actual contact with the barge and the stern of the tug has dropped due to either sinkage or bottom suction, but since the tug is now in an inclined attitude, is the thrust lifting the stern of the barge? Is the tug the weak link in this equation and responds to the squat affect to a greater factor? Since the tug is reacting at a greater scale, is the barge reacting, or reacting at a lesser percentage?
The challenge is still out there, considering all of the expert opinions that surfaced during the Patriots Deflate-Gate issue, there must be professionals willing to address this subject. A realistic calculation method is required and the findings will also need to be validated.
Some of the basic essentials for safe navigation appear to be going unrecognized therefore uncorrected. These affect electronic navigation including ECS, ECDIS, and RADAR as well as conventional course and bearing applications. The alignment of the navigation equipment being installed parallel with the centerline of the vessel is paramount. Modern radars have the ability to adjust the heading alignment thru a firmware interface. Many times I’ve observed installations with the Radar Heading Marker offset by a couple of degrees. Proper alignment of the radar heading is essential for transiting narrow channels, and avoiding allisions / collisions, especially during periods of reduced visibility. Crews have become desensitized to the basics due to over-dependence of AIS overlays on ECS and ECDIS displays. However, the same alignment issue is in play here, only worse. The gyro which provides the heading signal interfaced to all of the navigation electronics is in most cases askew, offset by a degree or more. The proper procedure starts with the installation of the foundation bracket for the gyro. The foundation bracket needs to be aligned with the centerline axis of the vessel, along with the slotted mounting holes on the base of the gyro allowing for finer adjustment of the housing. Then comes the Latitude compensator adjustment, the newer gyros handle this process internally with firmware thru a GPS input. The older units use either a potentiometer based adjustment or a mount based physical Latitude Corrector which slews the entire gyro housing on the foundation. The latter is found to be the one most misunderstood and set incorrectly.
First let’s address the gyro, assuming that a known and constant error has been recorded. With the vessel secure alongside a pier and the gyro running, loosen the foundation bolts slewing the housing until the error has been zeroed. I recommend utilizing a Sharpie and outline the original position of the bolt heads, also take care when tightening the bolts not to further slew the housing. Some of the newest models have a digital interface allowing the heading data output to be easily adjusted.
Next, verify preferably on a range that the gyro is aligned and the error is zero.
Second is the radar(s), note that the display paints by sweeping clockwise. This means that the left edge of a target is a reliable reference where the right edge of the target could be elongated. Considering this, while underway and holding a steady heading, steer towards a buoy a couple of miles away, if possible. Standing as far aft as possible and sighting the buoy in the center of the middle wheelhouse window, adjust the radar heading line to intersect with the buoy. If you are transiting thru slack current conditions with no set, and the heading and course over ground vectors aren’t on top of each other, and depending on company policies where “happy fingers” aren’t welcome regarding the adjustment of this equipment, consider requesting a technician to assist in correcting these input errors. AIS is generating a GPS over the ground solution based on your and the other vessel’s GPS generated COG, and isn’t applying the interactions of currents into the calculation. A properly aligned and tuned radar and visual assessment with your eyes thru the windows are to be trusted. Avoid ECS enhanced collisions due to misaligned electronics and potential AIS errors.
(International rules of the road meeting arrangements are a statement, not a request.)
Effective 2016 ECDIS became mandatory for many vessels. Additionally the implementation of Virtual Aids To Navigation (AIS Imaginary Buoys) to possibly replace real buoys is being considered. Do those generating this “guidance” really have any idea on how to navigate a vessel? Did they grow up with game consoles, and are now making critical maritime industry decisions based on video games experienced as kids and in college? There isn’t a reboot button or cheat code to enter in order to win this game.
Navigation, piloting, and handling of ships, tugs and barges is real life, it isn’t a game. Yes, I embrace all of the new technologies, AIS overlays and Virtual ATONs are wonderful gadgets, but they aren’t real. An AIS has a glitch and the target shifts or disappears, this can be the result of many factors. The over reliance on these devices is of considerable concern.
Installed on the bridges of vessels is the most outstanding 3D interface device currently known to man. This state of the art system has an exceptional reliability record, and doesn’t require an uninterrupted power source, code word WINDOW!
Utilize and rely on your “Mark 1 Eyeball” along with those windows!
(Maintain practical navigation skills.)
Currently the dependence on GPS & GLOSNASS continuously generating accurate location fixes has driven a nail into Dead Reckoning: the DR is dead!
If you are one of the many recent deck officers that has only known ECDIS, ECS Chart Plotters, and AIS overlays, "Don’t Get Caught With Your Batteries Down". Otherwise, there is a very strong possibility you will be lost!
Electronic Charting Systems
NOAA Current Predictions
NOAA Tide Predictions
Carrollton Gage (Trend & Forecast)
River Gages (All)
US Army Corps of Engineers
Dick's Towboat Gallery
Tug Boat Information
Ship Building History
This page of links was compiled at the request of fellow tug Captains.
Links verified 23 July 2020
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Philadelphia (Click Accept to enter site)
New Orleans (Regional)
San Francisco (Regional)
Mile 846 Ohio River, slipping fifteen into John T. Meyers Lock. Photo credit: Capt Cecil Duncan
Mile 327 Ohio River, Ironton - Russell Bridge. Photo credit: Capt Cecil Duncan
Tight Squeeze in a Private Canal. Photo Credit: Capt Mike Berry