Anchoring Downwind and Variations

#1

Our grandfathers in the Navy had so their own manner of anchoring. What they did was to steam with the tide and or wind, whichever was stronger, put the helm hard over and just as the ship started to swing, let go the cable on the run on the inside of the turn. Then they ran out to the required length, set the stopper and allowed the anchor and cable to snub the ship round into the weather.

This set the anchor and the whole operation was over in about four minutes. Walking out the anchor takes about half an hour or more. The Navy still seems to anchor in the same manner, only the brake is used a bit what is not good practice. By today’s standards this manner of anchoring may sound deeply shocking.

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Anchored Vessels Behavior in Wind
#2

The navy, everybody’s navy, seems to do things that are really hard on the equipment. Letting the anchor and chain snub up the moving ship would certainly give you a result quickly. Some kind of result. I imagine a burned brake band, or even mis-adjusted brake band would quickly leave all of your chain ranged neatly on the bottom as the sailor at the brake keeps spinning the thing hoping for it to grab. I’ll gladly spend the half hour on an uneventful mooring. If you use your anchors enough, though, things will happen. I was retrieving my starboard anchor one day, and it broke the water looking funny, and the AB called me to the bow to have a look-see. It turns out that when we dropped it, the retaining pin in the crown of the anchor finally got beaten out. It’s the 4" diameter steel pin that holds the shank inside the crown/fluke casting of the navy stockless type. If you drop your anchor enough, it will beat that pin out and the shank kind of wants to drop down through the crown/fluke casting. The problem is, the shank isn’t square in cross-section, it’s rectangular. So, if the tapered shank drops out far enough, it can rotate 90 degrees into the wrong orientation and then just jam halfway along when you try to pull the anchor. It was a real mess to fix, and we had to lift the whole shitteree on deck to do it.

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#3

Probably has to do with looking smart and snappy. Their schedule is flexible and tax payers are paying the bills so what the hell; "Full speed ahead and damn the torpedoes" is more fun than a slow and methodical approach.

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#4

Not as bad as it sounds because the anchor gear is being used to turn the ship, the force will be more or less at right angles to the motion, far less force needed to spin the ship than to stop it.

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#5

It’s still putting unnecessary stress on the ground tackle and brakes, etc…

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#6

Here’s a short clip demonstrating how it’s done :stuck_out_tongue:

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#7

Anchoring downwind is a good way to do it.

You can work up to it. A car ship moves relatively fast sideways in the wind. In about 15 or 20 kts of wind the ship can be stopped with the wind abeam and upwind of the desired spot, when the ship drifts over drop an anchor under foot, ship will turn up wind, pay out the rest of the chain, no engine or bow thruster needed.

Same as the Navy, the trick is the ship is being turned, not stopped. If the ship is going too fast the bow thruster can be use to help turn and take the stain off, once partly turned the engine can be used with the wheel hard over to control fore and aft motion.

Next step is to come in down wind and make a 90 degree turn, use the thruster and engine to position a bit upwind and abeam as above. It is a very quick way and not more strain on the gear than the using the standard missionary position.

If coming in down wind and the wheel is put over to stbd and then the engine is backed the ship will make a very quick stbd turn, the thruster can be used as well. If the anchor is dropped underfoot also during the turn… the ship will spin around and then while backing pay out the rest of the chain, use the engine and thruster as required to stop the ship and finish the turn when the wind is more or less dead ahead.

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#8

The usual way to anchor a ship is to stop the ship and put the engine astern. Then the anchor is walked out to just above the bottom, after which it is let go or walked out until the required length of cable is on the bottom.

Your anchoring scheme is much more sophisticated and is a variant of the Navy’s one. Also this approach to anchoring causes no heavy wear to the anchor system and takes a short time. What is important is to control the direction of the anchor cable at right angles to the bow until sideways motion has stopped and allow the vessel to rotate about the anchor until brought up.

Using the thrusters in the right way can be very beneficial. For anchoring operations in general a doppler SOG log is an valuable instrument to have on board.

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#9

In the standard method the speed and heading of the ship must be tightly controlled, car ships in the wind don’t like that.

Instead this way only the downwind motion of a single point on the ship has to be controlled, the point at the hawsepipe.

If the wind is at 90 degrees, from 90 to 30 degrees the downwind speed is moderated with the thruster. From 30 to 0 (wind dead ahead) the hawsepipe downwind speed is controlled with the engine (at first with the wheel hard over).

The function of the thruster and engine change during the operation. At first the engine is used to keep the hawsepipe point (more or less) directly downwind, later the engine is used to control the downwind speed and the thruster is used to keep the hawsepipe point aligned.

Meanwhile the wind is keeping the whole show on the road, tight control is not needed, basically the ship is getting set downwind and the mate pays out chain, just need to get the ship head into the wind while the mate gets his 7 shots out.

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#10

Here is a diagram, much simpler than my text.Start anywhere above the blue line. Red circle is anchor position. The black wavy line is the anchor chain being laid out. Final position is anywhere on the red line.

Not much precision needed, wind does the work.

The above is the passive method, the full active method is the same except at the second position at the red dot, the wheel is hard to stbd, the engine is full astern, the bow thruster is full to stbd, the captain is screaming on the radio and the chain is thundering out. This method can be can be adjusted between the passive and full active as required.

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#11

Here is downwind anchoring. In the second position if anchor spot is marked on the radar (or ECDIS) the ship true vector can be adjusted with the engine alone, here just a little stern way is needed to hit the spot. The radar vector will show when it’s right.

First position should be a bit further upwind but this is basically it. Everything at full is in theory only of course, can be done with less.

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#12

I should add that my previous post on losing an anchor off Bahrain was many years ago and vessels of the size of VLCC’s were just coming on the scene. The ship had a Doppler log which at the time was inoperative and the master while very experienced he had little experience with ships this size. There after the anchor was walked all the way out.

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#13

The vessel pivoting around the anchor as shown places far less strain on the cable and is the method I employed anchoring off Shanghai where the current is strong.

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#15

Anchoring a VLCC beast is I suppose another league. The ship must go astern very, very slowly, approximately 0.1 - 0.2 knots. This amounts to 8 - 10 cm/sec over the sea bed and is exceedingly difficult to judge accurately without sophisticated navigation aids such as a Doppler SOG log or GPS. Without these aids you should better not anchor.

Persons who want to control the mass of a VLCC by means of the windlass brake or even worse the motor, are not using the equipment as it was designed for and accidents are bound, if tried, to happen.

Because it takes a very long time to walk out the chain the tendency and danger is to lay out not enough chain. This can lead to dragging and eventually grounding.

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#16

I think that with your method it is rather easy to drop a second anchor, after dropping the first one, a bit further on and then fall back with the wind, while veering the cables, till the ship is brought up.

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#17

It does look that would be they way, rather come up drop one and then fall back as shown in the diagram.

But in general, two anchors violates the KISS system. On a forum seems like there is a preference for tasks that require a high level of skill. At sea a non-routine job entails higher risk.

Even if the captain is very skilled at anchor work it still requires skill on deck, so you need a good mate as well, and he needs a good bos’n. In any case even a good mariner can be having a bad day, or bad luck.

As I say it; “At sea the simple is difficult.”

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#18

I concur, I like simplicity too. It just occurred to me that with your method, if needed, dropping a second anchor is kind of a breeze.

I have a question about stopping a shipping for instance for anchoring, but also at other moments. We assumed, without the luxury of having a doppler log or GPS, that with the engine put astern the ship was stopped when the propeller wash had reached the bridge of the midships. I am curious whether this rule of thumb still works with today’s much larger container and other type of vessels.

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#19

I like simplicity too, and I just could never see myself steering my direct-reversible fish processor broadside to the wind into an anchorage populated by other fish processors. I can’t come from upwind and sail directly down, because that’s where the beach is. I knew of only one ship in our fleet that reportedly had a bow thruster, and it was the same ship which also had converted their engine room controlled direct reversible to wheelhouse control using a cluster of wires and hoses the diameter of a child’s hula hoop. Both systems were reportedly balky at best. My super power is the continuous expectation of ruinous calamity, so I proceed sloooowly into the anchorage from downwind, having walked out the anchor to within inches of the bottom. I found it easy to hover over my spot keeping the wind right on the nose. Sometimes, the AB walked out the anchor too far, and instead of retrieving it, I just left it on the bottom to help pin the bow and dragged it into position.

I agree that using a second anchor has its risks for sure, so I only did it when absolutely necessary to increase holding power, and then retrieved the secondary as soon as the need had passed. I never had a thruster, but if I had, I’m sure I’d have tried all kinds of cool acrobatics.

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#20

In my experience it is still a pretty good indication that the ship has lost its way.

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#21

Into the wind etc is the standard method. In general that’s by far the most common in my experience. I often use it as well under 15 or 20 kts. More than that on a car ship other ways are quicker and easier.

Drifting down wind is not really required unless it’s an anchorage with designated anchor circles, Port Suez or Port Said to name a couple. Even then if the turn is done right it shouldn’t be more then maybe a ship length.

Just use a big turn to knock off the speed and then back till the wind is anywhere from abeam to the bow, once stopped let go the anchor.

Here is MacElrevey:

Don’t really need a thruster, with the chain underfoot the ship will head into the wind. As long as the mate is paying out at the right rate. The thruster is used to slow things down a bit.

That said, for ships that handle well at low speeds in strong winds the standard method works fine.

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