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CARNIVAL TRIUMPH Tow on AIS
|Author||Topic: CARNIVAL TRIUMPH Tow on AIS|
posted 02-14-2013 09:56 PM ET (US)
I have been watching the tow-in of the cruise ship CARNIVAL TRIUMPH on the AIS tracking website VESSELFINDER.COM. It is quite interesting to watch the progress. The main towing boat appears to the ROLAND A FALGOUT, assisted by MOBILE POINT, LISA COOPER, and HAWK (all identified by their AIS transponders.
They are closing on the Alabama Cruise Ship Terminal. It will be interesting to watch the maneuvers around the dock.
[A sidebar discussion has been deleted from this thread--jimh.]
|Tom W Clark||
posted 02-14-2013 10:14 PM ET (US)
I find it interesting that www.marinetraffic.com shows sixteen different CARNIVAL ships but the CARNIVAL TRIUMPH is not among them.
posted 02-14-2013 11:23 PM ET (US)
It looks like Mobile is not covered in their network of receivers.
posted 02-15-2013 09:27 AM ET (US)
Here is a screen capture from VESSELFINDER.COM as the CARNIVAL TRIUMPH approached the passenger terminal last night in Mobile, Alabama. The wealth of information about vessel position, course, and speed that is available on self-organized information-sharing networks of AIS receivers is quite amazing.
posted 02-15-2013 10:22 AM ET (US)
The television news nabobs kept talking about the problem of navigating the ship in the channel because of the width of the channel, which they kept insisting was 400-feet, and the beam of the ship, which they reported as various dimensions; I seem to recall that "115-feet" was a popularly cited dimension. At no time was any concern expressed for the draft of the ship and the depth of the channel. It was as if this dimension were of no importance.
From what I can find, the beam of the ship is 36-meters and the draft is 8.3-meters, or 118-feet and 27.2-feet.
Using PolarNavy's fine chart plotter, POLAR VIEW NS, I downloaded all the latest official NOAA cartography for the area. The depth of the ship channel was not shown on the chart area, but appears in a tabulation. Here is the table:
The Alabama Cruise Ship Terminal is located in the portion of the channel called the Pinto Island Reach. A survey shows the least depth is 34-feet.
We had the nattering news nabobs continually worrying about navigating the channel because of the 400-foot width that would leave the ship with 282-feet of clearance, while below the ship there would be only about 6-feet of clearance from the bottom. Also, no mention of the state of the tide was made. The tidal range at Mobile is not very large. According to one source
as CARNIVAL TRIUMPH approached the dock the tide was rising to about a one-foot high tide.
As for the ship channel width, I did not see any notation on the charts, nor did I find it in the U.S. Coastal Pilot 5. Cf.:
I don't know where the figure of 400-feet came from, but the newsies all seemed to be using it. The chart and Coastal Pilot seem to be mum on the minimum width of the channel at any certain spot. In any case, one would have to assume the channel was sufficiently wide to permit two ships to pass without collision or grounding, so the notion that one ship could make way up the channel does not seem like too much of a concern. A news nabob said the ship had to navigate the channel "without any rudder." I don't know that anyone has determined that the ship had no rudder control. It appeared that the rudder was amidships, as the ship seemed to be able to be towed in a straight line. Even if a ship loses power, there typically is a means provided to move the rudder by application of manual power. It might take hundreds of cranks on a handle to move the rudder a tiny amount, but usually it can be done without any power assist.
One television news channel reported that navigation of the channel at night was normally not permitted. I could not find any mention of such a restriction in the Coastal Pilot.
One woman "anchor" kept insisting the vessel was "inching along." At that time the AIS showed the speed was around 4.3-knots. That is a speed of 310,632-inches-per-hour. Yes, that is really "inching along."
Problems occur on all ships. Perhaps the highest standard of ship maintenance would be presumed for the Cunard line ship QUEEN MARY 2. The QM2 has had a fire in their engine room. They have also had an explosion in their electrical plant that caused them to go adrift. This was the topic of a prior discussion in this forum. See
posted 02-15-2013 12:02 PM ET (US)
I did see one instance of what I presume was AIS track data being used. I do not recall which network employed it. They had a still image showing an aerial map view perspective of the Mobile Bay and Gulf of Mexico area. A white track line on the graphic was said to show the vessel course track. A presenter, part of the network staff, used some further graphic device to doodle a new line atop the graphic, more or less retracing the existing line, as he narrated events related to the tow, particularly the instance when a tow line was believed to have parted. Other than this, I did not see any use of AIS track data in the coverage.
Due to its size, the CARNIVAL TRIUMPH broadcast of its position via AIS was mandatory under the international rules. I was surprised to see that at least four of the vessels assisting were also transmitting AIS data. I don't think they all were in the mandatory category for AIS broadcast. I do find this whole AIS system to very interesting, and it is a source of great information at certain times.
posted 02-15-2013 01:28 PM ET (US)
On some further investigation regarding the notion of vessel movement after dark in the Mobile Ship Channel, I found that the Mobile Bay Harbormaster has control over vessel movement in the area where the CARNIVAL TRIUMPH was docked. The Coastal Pilot says, regarding the harbor regulations in the area around the Alabama State Docks:
I tried to reach the harbormaster, but the telephone number listed in the Coastal Pilot did not permit me to speak to anyone. It was answered with an automatic response that required I enter an extension. Not having any further information on extensions, I tried a few, like "0" or "100", and the harbormaster line then hung up on my call.
Next, I contacted a pilot on duty as suggested by the Alabama State Port Authority website and a telephone number given there. A fellow answered my call. I asked him if vessel movement at night was permitted. He said it would be unusual to move a vessel of the size of the CARNIVAL TRIUMPH at night.
In that regard, I believe it would be accurate to say that the arrival and docking of a vessel the size of the CARNIVAL TRIUMPH at night would be unusual.
The state port authority website acknowledged the arrival rather prosaically;
posted 02-15-2013 02:11 PM ET (US)
It is also worth nothing that in terms of beam, the CARNIVAL TRIUMPH was not the widest ship to arrive, even on the particular day. The port listing shows three vessels of wider beam are in port right now, one having a beam of 182-feet. In terms of length, in port we also have a 958-foot vessel.
It was frequently remarked that the CARNIVAL TRIUMPH was "the largest vessel ever to come to the port," but this seems hard to comprehend when on the particular day it arrived there were already vessels longer and wider in port. Perhaps the gross tonnage of the CARNIVAL TRIUMPH may greater, but certainly not its length or width. Longer and wider vessels were already in the port.
The vessel YUMETAMOU in the Port of Mobile Alabama today is both longer and wider than the CARNIVAL TRIUMPH, and has a deeper draft (10.1-meter or 33.1-feet). This sounds to me like she is bigger, at least in terms of width, length, and draft in navigating the channel. The cruise ship has a taller vertical draft.
posted 02-15-2013 07:41 PM ET (US)
Seems to me it would be impossible for a ship of greater beam, length and draft to displace less tonnage than a ship that has less of each dimension. Perhaps it would be just possible if the stern and bow of the longer, wider and deeper vessel had extreme rakes.
posted 02-16-2013 01:16 AM ET (US)
The tonnage is not weight but a measure of usable interior space.
posted 02-16-2013 09:53 AM ET (US)
I was incorrectly thinking of tonnage as another term for displacement or weight. As you observed, the Alabama Docks serves vessels of greater length, beam, and draft than the Triumph. Height above the water of the Triumph is probably much more than the Docks have handled before.
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