There is an emergency stop manoeuvre with the help of an anchor that is basically about the same as the ‘grandfather method’. The idea is the same in that the broadsided water resistance will decelerate the ship, turning reduces the speed. There is also the gradual reduction of engine movement and the controlled weight on the anchor that further reduces the speed.
Let’s assume that a ship is sailing on a river at a speed of 12 knots. The rudder is then put hard over to the side you can turn the ship. At that moment the anchor is dropped to the side of the turn. The engine is now brought to half ahead. When the speed is just over 10 knots or 11 knots the engine is brought to slow ahead. When the speed is just over 7 knots (say 8 knots), bring the engine to dead slow ahead. The instructions to the anchor party would be to keep pay out the cable as the weight comes. Their goal would be to not to stress the cable too much and hold the anchor until weight comes on the cable.
It goes without saying that the anchor should be dropped in an area of suitable anchoring depths.
The fastest way to stop a ship is by turning, it might not be obvious but the ship will slow down considerable faster if an ahead bell is maintained. The higher rate of turn more than pays for the ahead bell. I usually drop right to dead slow but it could be fine tuned more. Backing the engine is usually late in the game unless the ship is going slow to begin with.
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This is the method, Kennebec’s first diagram, I use when anchoring our light barge in more than a 10 knots wind. Our bow thruster is out of order, so I don’t have that, but it works well enough without. With any kind of wind a light barge, even with twin screw, it’s hard to keep that bow into the wind, soon as the wind has purchase on one side it takes off swinging downwind like a 560 foot long kite. If you’re already broadside to the wind the bow doesn’t have as much time to build up speed as it’s swinging. Seems to work well enough for us, though.
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That’s my experence as well as far as keeping the head into the wind.
It’s spoken of as “wind direction” but in reality the wind direction shifts at every gust. The other issues is the when the engine backs to port the bow swings. Hard to get it exactly right every time.
If the mate can “check” the swing early on when the amount of chain out is less it can reduce the stain on on the gear but the risk is a less skilled mate or a good mate having a bad day can screw up and brake too hard.
The bow thruster is not necessaly needed, at higher wind speeds it slows down the bow so the mate has more margin of error for paying out the chain.
Figure 4 – Example of Orthogonal Anchoring. (Illustration courtesy of D. Barber)
From Anchoring and Anchoring Equipment
The bow thruster is not necessaly needed, at higher wind speeds it slows down the bow so the mate has more margin of error for paying out the chain.
Or, the bow can be turned without the anchor down, using the thruster and the engine backing only.
Same graphic, new situation.
The ship has come in, made a turn to take off speed and stopped.
If the the ship is in acceptable position the anchor can be dropped (green circle)
But if if there are designated anchor circles (the blue circle) or some reason to be more precise then if the ship is stopped a little up wind the ship can be allowed to just drift down into position.
This is very easy to do, if the position is entered to display on the radar screen (or ECDIS) it’s simply a matter of getting the motion vector (shown in red) to intercept the anchor position.
MaElrevey discuses using leading marks and ranges to navigate by eye while the mate checks the position ect but using the vector is easier. In this case the vector will rotate clockwise with a bump ahead and counter-clockwise with a bump astern.
Good method for windy, rainy nights when just need to get the ship anchored and FWE.
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