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ContinuousWave: Small Boat Electrical
Electronic Boat Watching
|Author||Topic: Electronic Boat Watching|
posted 05-20-2012 09:28 AM ET (US)
There was a beautiful day last week with just perfect weather. I was at work, and decided it was time to take a long walk at lunch--I need the exercise after being cooped up all Winter. I set off for a walk, but I brought along my VHF Marine Band hand-held radio and set it to scan the commercial channels. I was about three blocks into my walk when the squelch broke on the radio on Channel 12 and I heard this call:
I have always wanted to see how a big freighter turns around in the turning basin of the Rouge River, and this was a perfect opportunity. I walked back to work and jumped in my car. I drove over to the Dix Avenue bridge, which is just downstream of the turning basin on the Rouge. I parked the car and walked over to the bridge. There was the 806-foot HON. JAMES L OBERSTAR just beginning to back out of the slip at the Severstal Steel dock:
The OBERSTAR continued to back, working her stern to Port and backing until she was close to the far bank of the river. Since she had just off-loaded her cargo, her draft was reduced to about 19-feet. The most recent survey of the turning basin shows the depth is 19-feet--she must be right off the bottom.
With her stern about as far off into the turning basin as possible, the 806-foot OBERSTAR began to swing her bow toward me, using her bow thruster on the Port side.
Eventually, the bow came around, and the OBERSTAR began to put on some forward turns on her propeller, slowing gaining speed toward the bridge, and coming right at me.
Using propeller thrust, her rudder, and her bow and stern thrusters the OBERSTAR lined up for the passage through the bridge. The OBERSTAR has a 75-foot beam and the bridge has a 125-foot horizontal clearance.
As the OBERSTAR passed through the bridge opening we were separated by only about 50-feet. Her bridge was just a few feet away
I've worked in downtown Detroit for 35 years, but this was the first time I happened to catch a big freighter turning in the Rouge River turning basin.
posted 05-20-2012 10:51 AM ET (US)
Quite some boat handling, all under single engine (I assume) and bow thruster. Is that a right hand prop helping work the stern to port? In the fifth picture it appears that a shot of bow thruster was applied to swing the bow to port, a correction I assume.
posted 05-20-2012 11:13 AM ET (US)
Do they offer cabins on these freighters to cruise?
posted 05-20-2012 11:41 AM ET (US)
In the fifth picture I believe the propeller is making turns for forward and the rudder is over for a turn to the Starboard, that is, to make the stern swing to Port. The bow thruster is on to push the bow to Port, to counteract the rudder trying to turn to Starboard. In this way OBERSTAR swings her stern to Port and keeps the bow aligned for the bridge. By the way, the total time covered by the pictures is almost an hour. These big boats move slowly in these tight situations.
Most of the Great Lakes classic freighters have a guest cabin. It is usually reserved for special guests of the ship owner. It is very hard to get aboard a Great Lakes freighter and stay in those cabins. It usually requires some sort of special "in" or connection with the shipping line. On occasion a cabin is donated to a fund-raising auction, and you can buy a chance or bid on the cabin.
posted 12-30-2012 10:07 AM ET (US)
One morning in the late Fall, I happened to check the AIS data for the Detroit River, and I noticed the vessel KAYE E. BARKER was coming down. As she often calls on the Rouge River, I thought it might be worth a quick trip downtown to watch her come up the narrow river. When the timing looked right, I assembled my portable AIS field station, and headed for the Jefferson Avenue bridge over the Rouge River.
About 25-minutes later I arrived, but the BARKER was no where in sight. I fired up the AIS rig to see where she was. The BARKER had already come through this point in the river and was now about a mile upstream, approaching the bridge at Dix Avenue. I was about to head in that direction when the bells went on for the Jefferson Avenue bridge, the guard crossing arms came down, and the bridge began to open. I looked again at the AIS display to see what was the cause. It was the vessel PETER R. CRESSWELL coming up the river, but in a rather unusual manner: she was backing up the river in reverse, assisted by a tug!
The approach of the CRESSWELL in reverse was more interesting than my original goal, so this trip turned out fortuitously. I got some interesting pictures of the big laker coming up the Rouge backwards.
As the CRESSWELL was making her way slowly past the bridge, I began to hear the distinctive minor chord of a train whistle, which seemed to be approaching from the southwest. The next obstacle in the river is a railroad bridge, just a short distance upstream. The bridge was still down, and I began to wonder if that train was headed for the bridge. A moment later the train appeared, and began crossing the river on the bridge. The CRESSWELL was not very far away, and this was turning into a rather interesting close call.
The train made it across and the railroad bridge opened in time, but I was surprised at the close coordination. I would have expected the railroad bridge to have opened sooner than it did. Too bad I didn't have my VHF Marine Band radio with me to listen in on that conversation.
As the CRESSWELL went past me on the bridge, I was just 40-feet away from her, and I yelled over to the mate on deck to inquire where they were heading. He replied they were going around the next bend in the river to the St. Marys Cement dock. This explained a few things.
Earlier in the morning I had seen the CRESSWELL (on AIS, that is) loitering in the Detroit River below the entrance to the Rouge River. Apparently she was waiting for the KAYE E. BARKER to arrive to let her go up the river first. Once the CRESSWELL would be at the St. Marys Cement dock she would extend so far into the river at that bend that it would block passage for a large ship like the BARKER. I presume the two captains arranged this on radio, otherwise there would have been a big problem.
I don't know if the CRESSWELL normally comes to the St. Mary Cement dock like this, by backing up the river. I suppose she could come in normally and then go up to the turning basin. However, with the BARKER already in that area for her unloading, there may not have been room to turn--another complexity of this evolution.
The next surprise for me was to discover a second tug, made up to the bow of the CRESSWELL and providing guidance and perhaps a set of brakes, if needed. Hiring two tugs to come to the dock must add a bit to the expense of loading or unloading here for the CRESSWELL. In contrast, the BARKER would come in and leave unassisted. I suspect the CRESSWELL would be able to leave the river without help of a tug, too.
This is how I spent a late Fall morning doing some vicarious boating. Although the skies were gray, the weather was quite mild, and it would have been entirely practicable to launch my own boat and go for a short ride. I think the temperature was in the 50-degree region. Without AIS this would have all gone on without my notice. It is very interesting to see how much ship activity goes on in the Rouge River when monitoring by AIS.
posted 12-30-2012 11:15 AM ET (US)
I just have to observe the following: Imagine how busy those waterways were in Detroit's heyday - with millions more people and factories operating at peak capacity. I bet those captains were forced to do similar ballet dances all the time. That would certainly be interesting to see!
posted 12-30-2012 01:41 PM ET (US)
Dave--One big difference from the 1960's to today would be the big plumes of black smoke coming from all the ships' stacks.
Also, I neglected to mention the excellent presentation on my AIS display of the CRESSWELL when making sternway. The icon of the ship was drawn correctly, showing her bow pointing downstream, and the plotted vector representing course and speed was drawn astern. This is possible because on these larger vessels with Class-A AIS there is a separate heading sensor that shows ship's heading, while the GPS provides data about Course Over Ground and Speed Over Ground.
posted 12-30-2012 02:03 PM ET (US)
The horizontal clearances of the bridges of the Rouge River are not particularly generous:
Railroad bascule bridge = 125-feet
The beam of the CRESSWELL is 75-feet, 10.5-inch. This means if the ship is precisely on centerline, it will have about 24-feet of clearance each side, except on the Oakwood Boulevard Bridge, where it will be down to about 21-feet, each side. Scaling that to an 8-foot wide small boat, the proportionate clearance would be just over 2-feet each side. However, your 8-foot beam boat will now be 75-feet long. That makes things more difficult. Oh, and, forgot to say, do it in reverse.
Also, I notice the draft mark on the CRESSWELL is at 25-feet at the stern. The chart says the minimum depth in the channel is 19-feet. The Master of the CRESSWELL must know something about the recent dredgings, or maybe they just come in there rubbing the bottom. When a large ship is so close to the bottom, it is said that maneuvering becomes difficult and unpredictable.
posted 12-31-2012 07:57 PM ET (US)
I took the photographs (above) of the CRESSWELL on November 15, 2012. I did not get around to writing the article using them until yesterday. Ironically, after I posted the article, I happened to check on AIS for any vessel movement in the Rouge River, and to my surprise there was the PETER R CRESSWELL once again at the dock of St Marys Cement. But even more interesting was another freighter, the HERBERT C. JACKSON, was coming up the river and appeared to be planning to go past the moored CRESSWELL.
By the time I got my AIS rig working and was able to record the data to a file (so I could play it back later), the pass had already begun. It looked to me like the CRESSWELL slipped her mooring at the dock temporarily, and backed up the river several hundred feet, still keeping her bow against the dock. This made enough room at the bend for the JACKSON to start to pass.
Then, as the JACKSON passed, the CRESSWELL pulled ahead while still against the dock, getting her stern out of the way. My screen capture below shows the maneuver at about the midpoint, where the CRESSWELL is moving forward but still alongside the dock.
One of the problems of these really low speed maneuvers being shown on AIS is the correlation between vessel speed and rate of transmission updates. Vessels that are moving very slowly send their position reports at longer intervals, about once every ten seconds. If they are "at anchor" the rate drops to once every three minutes. If my AIS receiver happens to miss one of those transmissions, there can be a gap of three to six minutes before you see any movement of the vessel on AIS. On the replay of my data recording, the movement of the two ships is a bit jerky due to these infrequent updates. Also, I don't know what sort of signal strength I am getting--I might be on the threshold of reception, so a bit of fade or noise could make me lose a transmission. The transmissions are very shorts bursts.
posted 12-31-2012 08:40 PM ET (US)
It just occurred to me that in the close pass shown above (as a chart plot of AIS data), there could have been some tugs helping. The tugs do not all have AIS transponders, and they don't show up on the chart plotter.
posted 01-12-2013 10:11 AM ET (US)
Here is a view of the ore dock at the Ford Rouge Plant in an earlier era. We see three ships at the dock, and a lot of smoke coming out the stacks at the plant.
posted 01-22-2013 04:35 PM ET (US)
Very interesting. Thanks.
posted 01-25-2013 11:25 AM ET (US)
Thanks for the very informative post with great pictures.
posted 01-27-2013 11:35 AM ET (US)
A couple of years ago around nine o'clock on a perfect summer night, we watched a big freighter back in to the channel at Grand Haven totally unassisted by tug boat(s) and all the way to the docks a couple of miles upstream on the Grand River. Impressive to say the least. No camera with us at the time. Bummer. It was cool to observe the procedure, the, bow thrusters, and especially crew members standing watch at stern and at several positions port and starboard.
posted 01-28-2013 10:14 AM ET (US)
I do find ship watching to be interesting, but, as I noted in the initial articles that began the thread, observation of the ships with electronic means can be a great aid to finding out when interesting maneuvers are going to occur that you might want to observe in person.
posted 05-15-2013 08:39 AM ET (US)
The Jefferson Avenue drawbridge, which Jim writes about above, was recently damaged when it was accidentally lowered on a passing freighter by a bridge operator who may have been intoxicated. See: http:/ / www. freep. com/ article/ 20130512/ NEWS02/ 305120133/ U-S-Coas t-Guard-drawbridge-Herbert-C-Jackson-river-rouge-detroit-ship-damaged
posted 05-15-2013 12:24 PM ET (US)
All accounts I have read of this incident have improperly identified the bridge type, calling it a drawbridge. The Jefferson Avenue bridge is a bascule bridge. Also, many accounts refer to this as a collision. A collision occurs between moving objects. I suppose you could consider the opening portion of the bridge a moving object, but the bridge itself is stationary. When a moving object hits a stationary object an allision occurs, not a collision. One article quotes a U.S. Coast Guard officer, and in the quote the word "collision" has been inserted in brackets. The officer probably said "allision."
Several accounts report the ship was passing under the bridge. This is not possible. The reason the bridge is a bascule bridge and must open is that ships cannot pass under it. Ships pass through the bridge opening when the bascule sections are raised. Most articles describe the incident as "ship hits bridge," but it seems more reasonable to describe it as bridge hits ship.
I believe at this moment the bridge has been moved to an open position and navigation is restored on the Rouge River, but highway traffic across the river on Jefferson Avenue will have to detour. The nearest other non-Interstate highway bridge is at Fort Street, about a mile away. That should make a mess of traffic for a long time. The bridge is about 90-years old, and I doubt that spare parts are available. It will likely require some considerable repair to be returned to working condition.
Moveable bridge types defined: https://en.wikipedia.org/wiki/Movable_bridge
posted 05-15-2013 03:39 PM ET (US)
A bascule bridge is a type of drawbridge. Cf. https://en.wikipedia.org/wiki/Movable_bridge.
posted 05-15-2013 04:29 PM ET (US)
According to one account relayed to me, the HERBERT C. JACKSON was coming up the Rouge River from the Detroit River toward the bridge. The bridge draws were lifted. Then, inexplicably, the bridge draws were lowered. The JACKSON tried to stop, deploying a stern anchor and one bow anchor, and going into stern propulsion. The JACKSON slowed but could not stop before striking the East draw. [This is probably a third-hand account, so don't take it as gospel--jimh]
The damage is not as bad I though it would be. The bridge appears to still be operable, as both draws have been raised. But the East draw is badly bent and there is a recognizable impression of the boat's bow:
(ASIDE: See defintion of draw at http://www.merriam-webster.com/dictionary/draw under noun , 2c.)
Of course, I couldn't resist driving down to see this myself. Too bad I wasn't monitoring the local VHF traffic last Sunday at 2 a.m.
posted 05-15-2013 04:45 PM ET (US)
For disambiguation of drawbridge and bascule bridge, see
posted 05-16-2013 10:32 AM ET (US)
An allision is a type of collision. See In re Mid-S. Towing Co., 418 F.3d 526, 529 n. 1 (5th Cir. 2005) ("An allision is a collision between a moving vessel and a stationary object."), citing Thomas J. Schoenbaum, Admiralty & Maritime Law, § 14-2 (4th ed. 2004); Also see Black's Law Dictionary (9th ed. 2009).
In this case, I would say that the bridge collided with the ship.
posted 05-16-2013 11:22 AM ET (US)
Since the draw was down and stationary, as was the rest of the bridge, I think the technical description is the ship allided with the bridge, and that is probably what the Coast Guard officer said to the press. The press reporter changed that into a collision.
To be more precise, I'd would say the ship allided with the East draw of the Jefferson Avenue bascule bridge, as opposed to reports that the ship collided with a drawbridge.
ASIDE: The journalists also had a bit of trouble with the company name of the ship operator, The Interlake Steamship Company. A couple reports said the ship was an "inter-lake" vessel. Well, all ships that sail from one Great Lake to another Great Lake are inter-lake ships, but the one in this incident was an Interlake's ship.
posted 05-16-2013 11:53 AM ET (US)
It is my understanding from various reports that I read on the internet that the bridge was lowered on top of the Jackson while the ship was passing through the bridge opening. See, e.g., http://www.claimsjournal.com/news/midwest/2013/05/16/228965.htm . Hence, my conclusion that the bridge struck the ship.
posted 05-16-2013 01:28 PM ET (US)
I read reports like that, too, but the location of the damage on the hull of the ship and the appearance of the damage on the bridge do not conform to the description that the bridge lowered onto the ship as it was already in the passage.
The momentum of the ship would have been so great that if the bridge lowered on it while it was making its normal way through the passage that the ship would have carried away the bridge span. The ship was carrying about 23,000-tons of cargo. The weight of the cargo alone is 46,000,000-lbs. The ship itself probably weighs half again as much, so the total weight in motion would be about 70,000,000-lbs. Even moving at a slow speed, that is an enormous momentum to be stopped by the bridge. The indentation of the ship into the span looks like it was only about six feet. To arrest 70,000,000-lbs in motion at say 2-MPH in a distance of six feet would require an enormous force. That force would be exerted on a lever arm of about 50-feet (the length of the span) to the pivot point on the bridge pier. I cannot image that the pivot of the span on the pier could have withstood that sort of force. I think the ship must have taken off most of her way and just gently struck the bridge span in order for the span to have remained mostly intact and in an operable condition, as it apparently is now.
Also, the location of the damage to the ship seems to be confined to the bow area and at a level about where the bridge span would have struck the hull if the span were fully closed.
posted 05-17-2013 07:25 AM ET (US)
"The JACKSON tried to stop, deploying a stern anchor and one bow anchor, and going into stern propulsion" All I can add is that somebody on the Jackson was wide awake and very fast acting. They deserve a medal.
posted 05-17-2013 01:00 PM ET (US)
I expect that at a minimum the U.S. Coast Guard will investigate this incident further. If they publish a report about it, I expect such a report to be interesting reading.
posted 05-19-2013 10:46 AM ET (US)
When trying to put a 700-foot ship though a bridge opening that is only 50-feet wider than the ship itself, I think the captain is always paying very close attention. The JACKSON is 75-feet wide and the bridge clearance is 125-feet. The ship has to pass through just about perfectly aligned.
If we allow the ship to come away from perfect alignment so that there is a 12.5-foot offset from bow to stern--that is half the clearance on each side of 25-feet--the alignment of the ship would only vary by
ArcTAN(12/700) = 0.98-degree
In other words, to get the ship through this opening, the captain has to align the ship with less than 1-degree of error from precisely perpendicular to the bridge. I think he is already paying close attention. It might be standard procedure to have an anchor ready to deploy in case something went wrong with the approach in normal circumstances.
The JACKSON was going to the Severstal dock. There is a turning basin up there, so typically the boats are transiting the bridges in forward propulsion on both inbound and outbound legs, and they usually do not hire a tug to assist them.
posted 05-19-2013 10:55 AM ET (US)
Here is a recording of the radio traffic between the master of the HERBERT C. JACKSON and the USCG in which the master reports the incident. The radio transmissions tend to confirm what I speculated:
--the bridge was lowered before the ship hit it
--the bridge was struck by the ship bow
--the JACKSON tried to stop with anchors and reverse propulsion but could not
posted 05-25-2013 11:44 AM ET (US)
[Began a sidebar discussion about word usage; this discussion has been deleted and has not been preserved or archived, as it really did not contribute much to understanding of boating, small boat electrical, or electronic boat watching--jimh]
posted 05-25-2013 04:38 PM ET (US)
Let me comment on my first-hand experience in maneuvering large ships.
Several years ago I was a guest aboard a USCG vessel, a large tug with an attached barge, creating a vessel of about 250-feet in length. I was quite impressed with the precautions taken when the ship was approaching the dock. A crewman and junior officer were stationed aft in the steering compartment where the ship's rudder and the engine that operated it were located. As the ship approached the dock, the officer put on a headset for an intercom to the bridge to permit immediate communication of helm orders. If the rudder engine or gear that operated by remote control from the bridge were to fail, the rudder could be operated by local control of the powered mechanism. And if the powered mechanism failed, a manual actuation system could be employed to move the rudder by cranking many turns on a gear-reduction input.
These precautions were standard operating procedure aboard the vessel any time it was involved in maneuvering in close quarters. When the vessel was underway and steaming in open water, the rudder room was not manned.
Based on this practice, there might be similar precautions used when a large ship like the JACKSON transits a very narrow passage like the Jefferson Avenue Bridge. Such practices might include being prepared to release an anchor if necessary to stop the ship in an emergency. This could account for the rather amazing reaction of the ship to the bridge closing as it was very nearly upon it.
posted 05-25-2013 04:47 PM ET (US)
Another recollection: I think the intercom was of the type known as a sound-powered intercom, which means it operates by making its own electrical power. That means the intercom would work even if the ship's electrical power were shut off. I think this is another example of redundancy and precaution in the operation of a large ship.
Wikipedia has a good article on sound-powered intercoms and their use on ships:
posted 05-25-2013 11:40 PM ET (US)
[More of the sidebar on word usage has been deleted--jimh]
posted 05-26-2013 07:05 AM ET (US)
Joe--don't get Jim started on the meaning of "issue".
posted 05-26-2013 09:09 AM ET (US)
Don--issue implies exogenous imposition.
MosslandingJoe--I am afraid you have dragged the topic from electronics to word origins. And you have now made me part of the topic of discussion. If you want to have a thread in which you give readers your opinion about me, you will need to start a new thread. In this thread the topic of discussion was electronic monitoring of boat movement, not your opinion of me and my language usage. Also, you will need to start your own blog if you want to continue to write at length about your opinion of me, as CONTINUOUSWAVE tries to concentrate on boating. We really don't attempt to collect and organize the opinions of individual people about me.
posted 05-26-2013 11:02 AM ET (US)
Regarding word choice, I always follow this motto: Never use a big word when a diminutive one will do.
posted 11-20-2013 03:03 PM ET (US)
It had been about six months since the Jefferson Avenue bridge was struck, and the weather being just wonderful for November, warm and sunny, I drove down to see what stage of repair the bridge might be in. A fence has been erected across the closed highway that approaches the bridge, so I could not get near to the bridge. However, I did come by a few more photographs of the damage, taken from the water side a few month ago. They showed more clearly the extent of the damage to the draw. In the image below, note how the diagonal braces are mostly deformed, albeit only slightly. The latest word I got--not authoritative but well-informed--is repair of the bridge has been abandoned; a replacement bridge will be constructed. That ought to be an interesting project. I wonder who one turns to for construction of bascule bridges these days?
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