Being aground represents status of ship in the same way as afloat, underway, making way, alongside, etc. It is actually physical touching of sea bed, due whatever reason, with hull even if the contact area is very slight. Beaching is intentional grounding. ‘Stranded’ implies the inability of ship to float free after being aground, by ordinary means.
Two things are very important in a shipboard emergency; one, the remedial action must be without any undue delay and two, correct order is followed, otherwise the purpose is defeated. In most grounding cases, an appropriate timely action can save a lot of trouble later. When a vessel runs aground or comes to a drydock, upthrust or ground reaction acts at keel. This has the same effect on the ship’s draft, trim, GMT, etc. as if, a weight equal to the ‘ground reaction’ force is removed at the point of contact.
In most grounding cases, the following must be remembered:
1. When a ship runs aground, the initial action is to run astern engines. Depth of water, nature of sea bed and possible damage to propeller / hull must be considered before attempts are made. Prolonged reverse propulsion should be avoided and no further attempts to move the ship by own propulsion should be continued if the vessel is not responding. The continued use of astern propulsion in a grounding situation may cause propeller wash to drive silt and bottom may aggregate in and around the hull. This silt and aggregate can be sucked into sea chests, fouling necessary cooling equipment required to maintain the ship’s propulsion systems.
2. Anchors to seaward should be quickly laid if possible to prevent the ship from working further ashore. Ground tackle should be rigged seaward as quickly as possible in certain situations. Rigging the ground tackle will help to keep the ship from broaching. When a ship is broached, scouring occurs. Sand and gravel under the hull is washed away by the action of the surf. Current produced by the swell, breaking against the ship sweeps around the bow and stern with great force. These currents remove ‘sea floor material’ from under the ship causing an extreme hogging condition that will eventually cause failure of the hull.
3. A quick check of soundings inside and around the ship should be made to get accurate assessment of the situation. Taking the soundings of sea bed around the hull, helps determining the slope and nature of the bottom. These soundings should be continued in the direction toward which the ship is to be hauled off, in order to locate rock formations, coral ledges or other underwater obstructions. Tidal streams which may affect the ship on her way out, should be noted.
4. The subsequent action may depend on the nature of bottom; aspect from the coastline or angle with respect to coast; the region and amount of contact with the seabed; tidal characteristics in that area; etc. A regular monitoring of draft at a point where the vessel is touching the seabed and tides must be done and logged down. This is because the change of draft at the point of contact indicates the rise or fall of tide. If the ship has to stay aground for two three days a good idea of tidal stream at the aground position will be available. Moreover, if the tide is rising, plans must be made to quickly make use of it and get away from grounding site. A negligence at this moment can make the ship a monument for future mariners.
5. The most powerful tool for refloating is the tide and the next powerful tool is use of simple stability principles involving change of trim, bodily rise etc. The rate of fall of tide in grounded area is compared with possible rate of rise of hull. Both these tools can actually supplement the power of propulsion.
6. While the ship is aground, releasing attempts should not be made to refloat the ship under her own power if wind and sea conditions indicate that there is a possibility of the ship becoming harder aground or there can be pounding or broaching to sea.
7. The ship should be weighted down and not lightened. The reason is; firstly, the hull does not hit the bed in pivoted condition; and secondly, damage caused by working and pounding of the ship on the bottom is prevented. She should be made to sit firmly on ground. This is accomplished by ballasting tanks and if necessary, flooding low compartments. Stabilisation of the grounded vessel can be obtained by dropping her anchors by using a beach gear or simply by adding weight through a ballast operation.
8. Submerged parts, (including seachests, the rudder and tailshaft sealing system) of the hull should be checked as to their general state and operationality. In cases where an underwater inspection is not possible or is limited due to meteorological conditions or characteristics of the site of the grounding, observation of the internal parts will provide results.
The underwater inspection, when done, should cover the following items:
i. The area of the hull in contact and its location,
ii. The existence and location of rocks,
iii. Penetrations in the hull,
iv. Cracks and openings in the hull,
v. Type of soil and accumulation of material or the effect of scouring.
(See the article on methods of Refloating with Limited Resources and Calculations)
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