Emergency Ship Towing

Professional Mariner Forum
1

Hello gCaptain,

I’m a Mate working with a couple Captains that have opposing views on what kind of tow gear to use and whether or not to tow out of the pins. I have the Navy salvage and towing manual, but thought maybe you guys might have some additional insight. [B]

Hook up scenario: [/B]
A 200’ AHTS needs to hook up to a 950’ dead ship offshore. The tow distance is 1,000nm possible 30’ seas.

Question 1[B]:[/B]
What tow/surge gear i.e chain, synthetic, wire combination would you to send up to the ship? [I]The connection evolution can not take longer than 20 mins once the ship pulls up the gear. Ships capstan works, no Smit bracket, only bitts on the deck. [/I]

[B]Towing scenario:[/B]
The same 950’ ship has no rudder or bow thruster control. Although the rudders are centered up, the ship continually begins to run while under tow. The 200’ AHTS is twin screw with a bow thruster. The tow pins are aft of the rudders while the gob chain and wire stops are 30’ up the deck.

Question 2[B]:[/B]
Would you consider towing out of the pins at 5kts with the ship continuing to run? [I]Meaning the tow wire stays over the rail at the wire stops 30’ from the stern.
[/I]
Any input or reading material is greatly appreciated:confused:

Bests,
Deviated

2

If you need to do a lot of maneuvering tow with the pins down.

3

I’d be interested to hear some more thoughts on these questions also.

4

Lots of thoughts here, but a great deal relies on how much time you have to get gear before hand, or do you go with what you have.

So…just thoughts:

  1. The synthetic shock line is normally (not always, just most common) used in the oil field because of the limited after deck space on the tug, and the limited means/personnel to work chain.

  2. Every large ship/offshore barge on a long distance tow (that I have done), has been done with chain. Again this assumes you have access to the chain.

  3. As AHTS says, [I]“you can not manuver with the pins up[/I]”, so the best way to do things is use a hog down cable or chain assembly (I assume this is what you mean with the term Gob chain.)

  4. THe Gob or hog down chain is meant to be the main control point, your tow wire stops along the head ache or bulwurks are emergency only. If the wire gets up to the stops, you are pushing things.

  5. In a perfect world, you would be able to send up two long wire bridles, one on each side of the bow, then your surge chain, then your main tow wire. If only one wire bridle is available, then of course send it to the bull nose, or as close as you can.

  6. Your wires, shackles and bridles should be set in accordance with your bollard pull. No need to send up over sized bridles, that just makes it hard to make up the tow. The same with the chain, but note there, sometimes you send up a longer then normal chain (more then one shot) due to expected sea conditions. By the same token you may only send up a half shot of chain due to size of the tow or the short distance of the tow.

Much of your scenario is like the Carnival Triumph and Resolve Pioneer tow into Mobile AL.

Anyone with other thoughts?

Ocean31

5

[QUOTE=Deviated;133018]Question 1:
What tow/surge gear i.e chain, synthetic, wire combination would you to send up to the ship? The connection evolution can not take longer than 20 mins once the ship pulls up the gear. Ships capstan works, no Smit bracket, only bitts on the deck. [/quote]

this is ridiculous…you’ll use the gear you have when you get there and as much of it that can be safely handled. One does not have time to go tow wire and surge gear shopping before they get a call to go snag a ship and who the fuck sets some artificial time limit…it takes as long as it takes and not a minute more or a minute less.

Question 2:
Would you consider towing out of the pins at 5kts with the ship continuing to run? Meaning the tow wire stays over the rail at the wire stops 30’ from the stern.

You would never run a vessel under tow if you could not steer it unless you are bucking into some hellatious weather and have to ease the strain on the gear. Regarding the pins…they put tow pins on tugs for a reason and that is to keep the wire centered on the roller over the stern and not chafing all over the place. Take the pins down when inside getting shortened up so one can maneuver

6

[QUOTE=c.captain;133030]this is ridiculous…you’ll use the gear you have when you get there and as much of it that can be safely handled. One does not have time to go tow wire and surge gear shopping before they get a call to go snag a ship and who the fuck sets some artificial time limit…it takes as long as it takes and not a minute more or a minute less.

Sorry, missed that part on the first post. [U]I would have to agree with CCaptain, there is no “time” in real life. It takes what it takes.[/U] And that “time” is more important then it first appears. I have given instructions on how I want a tow rigged up, the crew did what I wanted, and when it was all over, it was a case of [I]“Now what was I thinking, this is not going to work well” [/I] SO…tear it all or just part of it down, and redo the tow, that is the safe way. Piss everyone off, and look like a fool, yes, but if the rig is not right, take the time to redo. Safer in the long run. (and normally a faster tow also)

Of course, Duh…best to get it right in the first place, but the bottom line, it takes what time it takes.

Ocean31

7

let me add that you do not steam the tow if it can’t be steered for the simple reason that the tug would have to stay in front of the tow and that could mean all over the planet at the same time trying to keep in on some course to a destination unless that tug had way more HP than the ship and then the tension on the wire might keep the tow in step behind but even then it is dubious if it would work. How many tugs out there more HP than a 950’ ship? Even dead slow ahead on the ship might be more than a tugs bollard pull.

I often wondered how steaming/towing the NOBLE DISCOVERER from NZ to Puget Sound worked out and that was a ship with a working rudder!

8

If the ship has decent access to good bitts on deck I would go with some monster wire bridles or some big spectra bridles with some hefty chaffing gear at the chalks. 1-shot 3" chain and a pile of tow-wire out in the pins with a hold down. Doesn’t matter if the ship wanders as long as you have a fair amount of tow wire out. @950’ long the likely hood she would overrun you in the ocean is minimal.

9

Great input from C.captain and Ocean31. Thank you…

I wrote this as objective as possible to get some different input. The boat does have all types of tow gear, but theres some disagreement on how to set the gear. I’m going to wait to see if anyone has more input before I say what the three different tow set ups are being discussed.

As for the time frame… Of course there is no set time. It takes as long as it takes to get it safely connected. I said 20 mins to emphasize that many times due to weather offshore, the tug doesn’t always have the luxury of holding position for long periods of time to make the connection. Gear set up inshore at a dock can’t always be set up offshore as easily i.e. two hours holding position for a ship to make the connection could get dangerous. The connection gear should be able to be handled by the crew on the ship and not chafe through for long tows. This leads to my first question, What tow/surge gear i.e chain, synthetic, wire combination would you to send up to the ship?

C.Captain your input about the tow pins is very interesting… In short one Captain feels its okay to tow out of the pins for long periods of time over the bulwarks in order to keep control. The other Captain feels the wire needs to stay in the pins for the duration of the tow and only taken out for maneuvering when shortening up.

Thanks again for the discussion,
Deviated

10

One emergency tow procedure available (being towed) calls for stopping off the anchor in the hawseipe and breaking the chain at the first shot, then sending the ship’s anchor chain through the bull nose.

The assumption is however that the tow vessel likely will determine how to set up the tow.

11

I’ve been on many dead ship tows and large deep draft barges that would nose up into the wind. It made for an uncomfortable ride. If the tug had pins, many times we couldn’t use them. Most rescue jobs we did were with a shock line and wire pennant passed through the bull nose.

Many variables. How much wire and HP? What’s the draft of the ship?

12

[QUOTE=Kennebec Captain;133042]One emergency tow procedure available (being towed) calls for stopping off the anchor in the hawseipe and breaking the chain at the first shot, then sending the ship’s anchor chain through the bull nose.

The assumption is however that the tow vessel likely will determine how to set up the tow.[/QUOTE]
We used this method when taking a dead ship to sea. Once we had to pick up a chain pigtail and reattach at sea. We all lost some hide and lucky I was with the best deck crew I ever sailed with.

13

[QUOTE=injunear;133043]I’ve been on many dead ship tows and large deep draft barges that would nose up into the wind. It made for an uncomfortable ride. If the tug had pins, many times we couldn’t use them. Most rescue jobs we did were with a shock line and[B] wire pennant passed through the bull nose[/B].

Many variables. How much wire and HP? What’s the draft of the ship?[/QUOTE]
This would be called a " Break Away " wire. A well equipped towing vessel will always have one on board.

14

[QUOTE=Deviated;133041]Great input from C.captain and Ocean31. Thank you…

I wrote this as objective as possible to get some different input. The boat does have all types of tow gear, but theres some disagreement on how to set the gear. I’m going to wait to see if anyone has more input before I say what the three different tow set ups are being discussed.

As for the time frame… Of course there is no set time. It takes as long as it takes to get it safely connected. I said 20 mins to emphasize that many times due to weather offshore, the tug doesn’t always have the luxury of holding position for long periods of time to make the connection. Gear set up inshore at a dock can’t always be set up offshore as easily i.e. two hours holding position for a ship to make the connection could get dangerous. The connection gear should be able to be handled by the crew on the ship and not chafe through for long tows. This leads to my first question, What tow/surge gear i.e chain, synthetic, wire combination would you to send up to the ship?

C.Captain your input about the tow pins is very interesting… In short one Captain feels its okay to tow out of the pins for long periods of time over the bulwarks in order to keep control. The other Captain feels the wire needs to stay in the pins for the duration of the tow and only taken out for maneuvering when shortening up.

Thanks again for the discussion,
Deviated[/QUOTE]

I would prefer to have the ship stop off one anchor and the use the ships anchor chain as the surge gear. This would solve the biggest problem - chaffing. Also, veering more chain should stop , or at least reduce, the ship from yawing.

Of course everyone would prefer to keep the wire in the tow pins. And the tow could probably be controlled with the wire in the pins. If not, then it would become necessary to move the towing point forward of the rudders. The traditional way of doing that was with a. Gob Rope, a simple lashing between a shackle attached to the deck and a shackle riding on the tow wire. Today, it would be more likely to run a wire from another drum on the winch through a snatch block shackled to the deck and ending in another snatch block riding on the tow wire. This can be adjusted by hogging the tow wire down close to the deck and moving the towing point forward of the rudders. It can also be let out to let the wire run over a quarter while making a turn.

However the better approach would be to stop the ship from yawing from side to side. First I would try adjusting the trim of the ship. It should tow better trimmed by the stern. If towing from a single point, the ship might settle down off to one side, probably to leeward, by cranking the rudder over about 5 degrees to leeward. Alternatively, if towing on bridle with a leg to each side of the bow the ship might settle down off to one side by shortening, or lengthening, one leg of the bridle. Another alternative might be to trail something astern of the ship, such as a string of Yokohamas.

For a long tow it would be well worth investing the time into finding a way to stop the ship from yawing back and forth across the stern of the tug. Why tow the ship for 2000 miles zig zagging back and forth over a 1000 mile base course, if you don’t have to

15

Not for nothing, but in the case of a real emergency close to shore I’d ideally use the ship’s emergency tow gear (tanker) on the stern. Slick rigs… From a liability point of view its the best bet for the tugboat company. Obviously not a solution for a long ocean tow, but enough to get things under control until you can rig something proper.

I’d have to agree that the ship’s anchor chain through the bullnose would be best balancing time and effectiveness. More chain could be added/subtracted and you’d have good confidence in the connection point on the ship. This makes it easiest on both crews from my perspective, allowing the connection to be made on the ship’s deck vs the tug’s.

16

Wow, thanks for the replies.

To answer some of your questions:

[B]rschrew:[/B] In this scenario, the ship has solid bitts. We have 600’ of 9" circ spectra, one shot of 3" chain, two 2.25" x 120’ pennants, and two 2.25" x 75’ pennants

[B]injunear:[/B] The tug has 3,000ft of 2.25" wire with 8,000hp. The scenario tow has a 35ft draft and high windage.

[B]Kennebec:[/B] Stopping off the anchor and sending the chain through the bull nose is certainly another option. Our tugger can pull the chain down to our shark jaws to make the connection. Or we could send our gear up to make the connection. Like many tugs, we also have an Orville hook to grab chain if needed. I’d have to check, but I think the salvage manual stresses the chain should not be secured to the windless alone, but stoppered of at another point.

[B]Tugsailor:[/B] Chaffing is certainly a major consideration especially for long tows in any kind of weather. We could easily use the second drum with a snatch block to control the hogging. [I]Never thought of that, but then again I’m just a Mate:D[/I] Again the scenarios are made up… But they do reflect real experiences and possible future tows. The ideas of trimming, shortening a leg, and trailing Yokohama’s are certainly noted. I will make an opinion on that advice towards the end of the thread. I still want to keep this objective.

[B]z-drive[/B] In this scenario the ship is offshore. However, in the case the ship was in danger of running aground or already aground, we would immediately send up a spectra line to the ship via line throwing gun or monkey fist if we can get close enough. Our gear would be ready to deploy and the evolution shouldn’t take more than twenty minutes once in position. Including surge chain would be up to the captain but wouldn’t be a problem.

Bests,
Deviated

17

Is there a riding crew on the ship? I’ve been on tows where the rudder could be shifted to help minimize swing. Anyway, 900 ft with 35 ft draft and 8000hp is a handful. Good luck!

18

[QUOTE=Deviated;133061]

[B]Kennebec:[/B] Stopping off the anchor and sending the chain through the bull nose is certainly another option. Our tugger can pull the chain down to our shark jaws to make the connection. Or we could send our gear up to make the connection. Like many tugs, we also have an Orville hook to grab chain if needed. I’d have to check, but I think the salvage manual stresses the chain should not be secured to the windless alone, but stoppered of at another point.[/QUOTE]

This type of towing is outside the expertise of most ship’s crews. It would increase the likelihood of success if a experienced salvor crew was put on the ship to assist the ship’s crew. Just one person to direct the ship’s crew and facilitate communications between vessels would help. Of course that may not be possible or practical.

If I was to set up to be towed, no outside advice was available and the plan was for ship’s gear to be used l would prepare using the ship’s tow plan which has several options. For a 1000 mile tow I’d use the anchor chain. In the OP 30 foot seas were specified, that’s heavy weather, sailing in that is tough, much less towing.

I’d stop off the stbd anchor and break at the 1st shot (shackle). I’d then led the chain out the bull nose with a tag line back to the deck.

If I was drifting I’d be beam to the wind drifting at about 10% of wind speed ( 2 kts drift speed in 20 kts of wind for example). I"d have several heaving lines and all my line-throwing guns ready on the bow. I would expect the tow vessel to “cross the T” forward, At the closest point I’d send a heaving line across, then a 600’ line about the size of my thumb followed by a 600 foot (100 mm ?) synthetic mooring line. Next the anchor chain. I would expect the two vessel would have to be fairly close together to pass, otherwise there is going to be a very heavy bight. Maybe a transition from mooring line to anchor chain could be done while under tow at bare steerage, adjusting the length as required. Once the anchor chain was paid out it would have to stopped off somewhere. Probably by wire to the mooring bitts. I have gear aboard for this purpose. For sure you don’t want towing loads on your anchor windlass.

Best case scenario would be to get an experienced crew aboard to assist, being towed is outside the experience of most ship’s crews.

19

One look is worth a thousand words …

For every complex problem there is an answer that is clear, simple, and probably wrong !
H. L. Mencken

No problem can be solved from the same level of consciousness that created it !
Albert Einstein

20

Listen to Tugsailor.

I’m chuckling at the example because it sounds exactly like a tow we made.

The ship passed chain, we made it up on deck to our towline, let out abt 3000 ft of 12 inch nylon and towed like hell.

The nylon really gave a nice ride. Lotsa fussing with chafing gear when towing on nylon but all the stretch really helped. Skipper’s choice, most cap’ns preferred the wire.

Kiting wasn’t a problem, but if you have to tow a ship with no rudder at all, rig a sea anchor off one side of the towed ship’s stern. Something serious that makes a nice drag and as far outboard as possible. That’ll point the bow of the tow off to one side and you’ll have no kiting. Done it worked a treat.

Lots of good ideas / experience in posts above. Maybe The Forum acting at its finest.