Bookworm wrote:Someone with knowledge, please enlighten me. Why would a vessel drag their anchor as they pass through miles of ice-choked water? I'm not making sense of the scenario as reported.
In the navy, if a good wind came up on us without much warning we'd drag anchor for a bit. Certainly not miles though.
In reading the article, I do not get the impression as though the anchor was dragged for miles. However one can conclude that the anchor dropped at the right time (or wrong in this case) and dragged unintentionally could happen. Never a worse time for an unattentive anchor watchman or a faulty capstan that's for sure.
Someone with knowledge, please enlighten me. Why would a vessel drag their anchor as they pass through miles of ice-choked water? I'm not making sense of the scenario as reported.
SailorDoug wrote:In the 70’s Ontario hydro did a exsenive survey of Lake Erie in preparation of laying power lines across the lake. They found numerous deep grooves that they attributed to ice. The explanation was that broken ice in the western end of the lake would gather and roll as the pervalling winds moved it east. These large balls of ice needed to be quite large to have enough mass to leave measurable tracks in the bottom.
Power plant and lines project where abandon.
At what depth were these grooves that they think were caused by the rolling balls of ice?
In the 70’s Ontario hydro did a exsenive survey of Lake Erie in preparation of laying power lines across the lake. They found numerous deep grooves that they attributed to ice. The explanation was that broken ice in the western end of the lake would gather and roll as the pervalling winds moved it east. These large balls of ice needed to be quite large to have enough mass to leave measurable tracks in the bottom.
Power plant and lines project where abandon.
The deep trench runs from far out to the west, above White Shoal Light, all the way through the Straits. Much of the shipping channel runs over the trench, which is generally about 285 ft deep in the middle. Near the bridge but on either side, there are holes that run to about 325 ft deep. The cables and pipelines are west of the holes, but they do pass through a long stretch of 250-280 ft depths. See this link: http://geo.msu.edu/extra/geogmich/mackinacchannel.html
Jon Paul wrote:The cable/pipeline area is within 1 mile west of G3 and R4 which are the buoys marking the shipping channel west of the bridge. NOAA chart 14880 clearly shows this to be an with average depths of 100'-120'. The area of 200' area is more than a mile west of the lines.
Jon Paul. I'm certainly not trying to argue or question your local knowledge, but doesn't Enbridge's Line Five cross from Point la Barbe to McGulpin Point, which is slightly further west than the electrical cable? If so, chart 14881 seems to show a sounding of 224 feet within that area and one of 291 feet just outside the pipeline area.
Thanks for the updates. The Coast Guard and the various State agencies seem to be keeping pretty tight lipped, perhaps rightfully so since this may have legal or even criminal ramifications.
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The cable/pipeline area is within 1 mile west of G3 and R4 which are the buoys marking the shipping channel west of the bridge. NOAA chart 14880 clearly shows this to be an with average depths of 100'-120'. The area of 200' area is more than a mile west of the lines. LCA courses funnel at those 2 buoys and that was where the track through the ice had been made which was clearly evident on the satellite photos I've seen and also saw myself as I crossed the Bridge several times during that week. There would be no rational point to deviating from the channel which held the track.
A salvage team is currently here and first day weather permitting an ROV will do an in depth survey of all utility lines and pipelines. Divers are part of the salvage team and will assist with the ROV but due to a 7 knot current, water temperature, wave conditions and roving ice, they will be limited to surface action.
Guest wrote:If the water there is 100' or more deep how could it be ice damage to something laying on the bottom?
The shipping channel is 100' or more in depth. To cross the Straits the utilities go from a depth of only a few feet to over 200. I haven't seen a description of where the damage occurred, but it wasn't necessarily in the shipping channel. It could be close to shore, even if it is an anchor or hull strike. Ice goes wherever it wants to in the Straits and vessels don't always stay where they should be.
Guest wrote:If the water there is 100' or more deep how could it be ice damage to something laying on the bottom?
Well, it's on the northern half of the Great Lakes, so the gravity of the water is inverse, therefore the ice goes to the bottom of the lake instead of floating on top! Ha! Sorry, had to poke some fun in there.
The ice in the Straits is significant year after year, but I highly doubt it has ever been 100' significant!
SailorDoug wrote:It could be ice! That maybe something that no one wants to admit. For it to a ship it must of dragged anchor to get two transmission lines. With AIS picking a ship that did this would not be too hard.
If it was ice that is a lot of liability financial and politicaly with no cures.
Glad to see someone else is putting forth that possibility. Based on previous posts regarding this being a "no anchor" zone, it makes sense.
It could be ice! That maybe something that no one wants to admit. For it to a ship it must of dragged anchor to get two transmission lines. With AIS picking a ship that did this would not be too hard.
If it was ice that is a lot of liability financial and politicaly with no cures.