in

SEAMANSHIP

DRAGGING ANCHOR

Generally speaking, once an anchor starts to drag, the vessel gathers sternway, and this may become excessive. Prompt action is necessary. However, there are exceptions, and vessel riding out a gale has been known to drag slowly and steadily for some days at roughly a mile per day.

If the wind rises, extra cable should be laid out to ensure a bight lying on the sea-bed under conditions of yaw and pitch. Pitching can be partially prevented by trimming the ship by the head. Yawing is likely to start the anchor dragging, and one of three actions is advisable:

1. Let go the second anchor underfoot at the centre of yaw. This is an excellent plan if the brake is held just slackly. If the first anchor starts to drag the second will bite and its cable will render itself. The noise of this gives warning of dragging, and the second cable regular practice, whether or not the weather is bad.

2. Let go the second anchor at the extremity of yaw and veer both cables so that the ship rides comparatively quietly to her two anchors.

3. Steam up to the first anchor, sheer away, and let go the second anchor. The first cable is hove in while approaching its anchor. Both cables are then veered so that the vessel rides quietly with an anchor fine on each bow.

If a hurricane is approaching, the vessel should leave harbor if other vessels are anchored close by, if the holding ground is other than excellent, or if the harbor is un-sheltered. Departure should be made well before the storm arrives, otherwise the vessel may be caught out side with too little sea room and drive ashore. If remaining in harbor, action (3) above should be taken and cables veered away.

Once a vessel begins to drag, more cable should be veered. It should not be surged out slackly, otherwise the cable may part as the vessel brings-to. By veering it, the vessel may be brought up gently. The second anchor should be let go in good time, otherwise it may be found that so much cable has been veered on the first anchor (say 8 out of 11 shackles), that very little can be veered on the second (in this case only 2 to 3 shackles). Engines should be used to relieve stresses. If there is room it may be better to heave up and seek better holding ground.

Read More: SEAMANSHIP

What do you think?

Written by Admin

Comments

Leave a Reply

Your email address will not be published. Required fields are marked *

Loading…

0

UNCLOS

Which international convention requires a register of the lifting appliances to be kept on board a ship?