That was pretty close to intentional disposal at sea. It’s hard to believe that anyone is that dumb.
wasn’t it a few years ago someone was towing two old tdw mudboats side by side to scrap and had problems too?
when could this scheme be practical?
is this considered normal, anywhere?
Maersk has plenty of towing expertise and experience available within the organization, which makes it more difficult to see how they ended up with this solution.
Tandem tow on two wires (Solution 1) MAY have been discounted due to the shallow water along the early part of the tow route.
I was a part of that fiasco, luckily I was still a mear AB. The captain of the towboat was a seasoned veteran who should have known better.
If shallow waters were an issue, the first solution that Maersk should have considered was: No Tandem Tow due to shallow waters.
However, I can say that we routinely do tandem tows on the West Coast of the US that must transit shallow waters. After a quick look at the North Sea charts, I do not see any abnormal shallow water problem. Certainly, not a shallow water problem that could not be mitigated using time tested methods.
We also routinely do tandem tows using an under-rider and a single drum winch. Also, tandem tows are routinely done with a single drum winch utilizing a “Canadian-Link” in the tow wire. A double drum winch is not necessary for a tandem tow. Then there is also the basic time tested “Honolulu” tow make up (tows connected to each other In series.
While I don’t doubt that Maersk has a lot of —towing experience — in this fiasco Mareask demonstrated a total lack of towing — expertise.
This Maersk tow was not ignorant or inexperienced, it was insane.
Tow commenced in Fredericia, Denmark and had to pass shallow water to get to the North Sea: https://www.google.no/maps/place/7000+Fredericia,+Denmarkemail@example.com,8.4454582,7z/data=!4m5!3m4!1s0x464c9a751a58136b:0xc981ee88c9488cd3!8m2!3d55.5689298!4d9.749517
Besides, the English Channel is fairly shallow along the required TSS lane.
The M.Seeker/Searcher are relatively deep draft, even when in light condition, unlike barges.
I do agree that the best solution would have been to make two separate tows, or reactivate one vessel to tow the other.
I do NOT think Maersk would deliberately sink the two vessels, since they are far too concerned of their image.
Beside, the two vessels were already sold and being towed on behalf of the buyer, so even a less conscientious operator would have little incentive to do so.
Take a look at the water depths going into any US West Coast port, except Seattle. Most ports require a bar crossing on-the-wire into the mouth of a river. Take a look at the water depths in the northern half of the Bering Sea.
What is an under-rider and a Canadian link?
I believe an under-rider is a length of wire that shackles into the tow wire at the heart shackle / fish plate, passes under the lead tow, then comments to the aft tow’s pennant.
An under-rider is a wire pennant with a poured socket on each end. A typical under-rider is about 700 feet long. It is shackled to the end or the main tow wire and runs under the lead barge to next barge in line.
Most often, light flanges are added to the winch-head on the towing winch to form a reel to store the under-rider. Some boats have a light duty hydraulic reel up on the boat deck to store the under-rider. On rare occasions for a one time tow, I have seen an under-rider laid out on the deck of the tug or the barge.
The Canadian-link. Is a manufactured product that can be bought off the shelf. It is essentially two poured sockets connected by three links of stud-link anchor chain. The stud is removed from the center link and replaced by a piece of heavy flat bar with a hole drilled through the center.
Typically, two layers of tow wire (about 700 feet) are cut off the main tow wire next to the side of the winch drum. The main tow wire is attached to the socket on one end of the Canadian-link, the piece of wire that was cut off is attached to the other end. Now the Canadian-link is in place set into the main tow wire. The level wind fair leads on the winch must be offset to allow the Canadian-link to pass. The level wind must be hand operated when the Canadian-link is stowed against the side of the drum (yes it makes a lump on the drum).
The last barge is attached to the end of the tow wire, the lead barge is shackled into the Canadian-link. In effect, the end of the main tow wire becomes an under-rider.
Many tugs in British Columbia have the Canadian-link. It is less common on American tugs.
You are talking relatively light gear here, not what you find on vessels like the Maersk Battler, with a bollard pull of 230 m.t.
Not that tandem tow is not possible with large towing vessels like the Battler, with a triple drum winch and large storage drums for spare pennants,
With 86 mm. diam. (3 1/3") tow wires none of the gear can be man handled, like for your barge tows with small tugs, however.
PS> I attended the BP test for Maersk Seeker when new.
The size of the gear scales up or down to the sizes of the tugs and tows as required.
A 130 foot, 3600 hp tug with a single drum winch can tow two heavily loaded 400 foot barges along the coast or across the Pacific. It’s been done hundreds of times without incident. Although a twin screw 7200hp tug with a double drum winch would be more typical for barges of that size today.
The Canadian tugs routinely tow three barges in BC. For example look at the Seaspan tugs (an old Canadian company now owned by an American).
Look at this video to see how dangerous rigging tows can be: https://www.liveleak.com/view?i=3f1_1504069724
Yes I do not say that tandem tows with different methods are something new, or special to the US or Canada. I have been involved with several, both barges and scrap ship tandem tows, using different methods.
I only point out that when you are dealing with really heavy gear, like on the M.Battler, it takes winches and lifting gear to match to handle the operation safely. Not like in the video above.
I don’t understand why they did not put the other tow pin back up to trap the tow wire so that could not happen.
Rigging tows is dangerous. Especially, when there are too many over complicated pieces of mongrel gear in the make up.
This why it’s preferable to use the right equipment and avoid half-ass mongrel gear.
Like “under-rider wires” and “Canadian links”, especially with really heavy gear.
Those Maresk supply boats could very easily be towed with an under-rider. 2" diameter wire would be much more than needed. The long deck on an AHTS , the tow pins, shark jaws, and the tugger winches make it relatively easy and safe to handle the under-rider.
For a one way tow like that the under-rider could be easily laid out on deck with a crane and stopped off. It only has to be set out and heaved up once – in a protected anchorage with assist tugs made up to the tows. It’s a piece of cake.
The Canadian link is safe and easy to use. Handling the under-rider is more dangerous, but less dangerous than handling the chain surge gear which is routinely used. It does take some know how.