How to break out an anchor?

If an anchor in soft clay has been subjected to high tension, there will be a vacuum behind the anchor head. When the tension is taken away, the anchor falls back into the vacuum and the effect of the falling anchor results in a deeper penetration of one or more centimetres. If these high load jerks are repeated many times, the anchor can penetrate an extra 1 to 5 metres. This is the reason why it is so hard to break out anchors after stormy weather.


When the pendant line is too long, the rear side of the lower tripping palm might bite and obstruct an easy pull out.


Do not try to break out an anchor with a vertical pendant line in rough seas, because the pendant line will break by a shock load when the anchor handler rides the waves.


The good way:
A good way to break out the anchor is pulling on the pendant at an angle of approximately 15 degrees to the vertical, away from the rig. Then there is some elasticity in the system. If this is unsuccessful then you must try the PETER KLAREN method. This method has three advantages:

• You do not need to drag the embedded anchor cable through the soil
• The tension in the anchor cable reduces the suction of the clay on the rear sides of flukes and palms.
• The rear side of the head will not be filled with clay.

Sequence of this break out action:

• Ask rig to reduce tension in anchor cable just above minimum (no slack).
• Manoeuvre stern above anchor with bow in direction of rig.
• While heaving in the pendant wire as much as you can.
• Look out for too much tension in the pendant in rough seas.
• Then slack 5-6 metres of pendant wire (not more).
• Head in the direction of the rig under full power.
• And ask the rig to tension up the anchor cable to 40-80 tons (see sketch)
• As soon as the rig reports that the tension drops, the anchor is loose.
• Anchor handler must change course 180 degree, stop engines and haul in sufficient pendant wire until the anchor is well clear off the bottom.
• Let the rig winch now haul in the anchor cable, pulling anchor and anchor handler towards itself.