SOPHIY ALGERIA SKIKDA port
|No.||Types of Measures to Be Taken|
|2.||PERFORMANCE PROCEDURE OF THE RESCUE AND SALVAGE OPERATION|
|3.||LIST OF DISCOVERED HULL DAMAGES|
|4.||OPERATION WORK SCHEDULE|
|5.||CALCULATIONS FOR SUBTENDING THE VESSEL|
1. EXPLANATORY NOTE
1. General Information
Getting the m/v Sophiy afloat is performed for the purpose of the harbor clearance. The refloating task includes establishing of water impermeability of the main subdivisions, setting it afloat, subtending it off the ridge, and taking it out to deep water. At the delivery time the vessel shall have floatability and stability which would not raise any concerns.
The general schedule of the works is presented in a document titled A Performance Procedure of the Rescue and Salvage Operation.
2. The Project Brief
The following documentation has been developed within the scope of the project:
- An operation work schedule.
- A ship sitting chart.
- A depth table.
- A list of discovered hull damages.
- A list of involved workforce and means.
- A list of consumable materials.
- Calculations for subtending the vessel.
- A checking calculation of stability.
- A structural midship section of the vessel.
- The hold layout.
- The Engine Room layout.
- A standard bolt eye.
- A pressure clamp.
- A standard sealing of an air pipe.
- A standard mounting of a mat.
2. Principal solution to getting the vessel afloat
2.1 Based upon a target inspection conducted within the period of June, 09-14 this year by «Morskie Glubokovodnye Sistemy» LLC, it is necessary and appropriate to restore the floatability of the Engine room, the hull, and some of the double bottom and double board tanks, as well as the fresh water tanks. It is unpractical to perform sealing actions on build-in board tanks No. 15 and 18.
2.2 Sealing of the hull is planned to be achieved by plugging breaches and seams in the boards and the deck for the purpose of draining with pumpage. According to the data available the Engine room is more advantageous to be drained by squeezing out the water by means of a compressed air supply. It will require a sealing of the upper part of the subdivision.
Draining of the double bottom and double board tanks is also appropriate to be performed by means of a compressed air blowing of the subdivisions.
2.3 It is planned to strip the covers of the cargo hatches, cargo cranes and some other structures before the commencement of the subtending in order to decrease the soil response and to increase the stability. Those structures are planned to be placed into the hull of the injured ship after it is taken out to deep water.
2.4 The subtending of the vessel off the ridge is planned to be achieved by slews of the fore end to the right.
2.5 A vertical fold of the boards’ outer plating in front of the deck superstructure and the Engine room raise a serious concern as to the overall strength of the ship hull. There is no guarantee that the vessel will not break here even without any human actions. Proceeding with that operation we should understand clearly that the highest risk lies in the possibility that the remaining overall strength of the ship hull may turn out to be insufficient. If the hull breaks in the vicinity of transverse frames 28-30, stability of the after body will be insufficient and the fore end will require a much larger scope of additional works in order to setting it afloat.
3. Environmental provision of the operation
3.1 The environmental provision of the operation is exercised by the port efforts.
3.2 Fuel and oil reserves have been removed from the injured ship. Nevertheless there is an inevitable flushing of oil products out of the units and systems during the draining of the Engine room that may lead to pollution of the sea. Oil retention seabooms shall be placed around the vessels (250 m with six anchor sets) before the commencement of the draining of the Engine room in order to prevent the pollution. The water surface in the Engine room shall be treated with sorbents. The transfer of the injured vessel during the subtending should be performed along with a simultaneous transfer of the boom defense. After the vessel is taken out to deep water the boom defense shall be drawn away from the vessel together with collected oil products inside, the sleek field shall be separated from the water by means of a skimmer and then pumped into a receptacle or a tank of a special skimmer ship.
4. Provision of the work safety
4.1 The standard safety precautions for rescue and salvage operations prescribed by corresponding guidelines are to be observed during the operation.
4.2 A special attention should be paid to monitoring of the hull condition in the area of the vertical fold of the outer plating. A check inspection of the spot shall be performed daily, and it shall be constant during the subtending it off the ridge.
4.3 During the loading of previously dismantled units into the hold the measures shall be taken so that the load would not disturb the sealing of the deck and the boards and so that it would not puncture the deck in spots of protruding structures.
2. PERFORMANCE PROCEDURE OF THE RESCUE AND SALVAGE OPERATION
- The operation project development and documentation approval. The term of the project development – to July 10.
- The preparatory stage. Considering the production of graving pieces – 7 days.
- Deployment on site. — 1 day.
- Measures to be taken in order to prevent the object from drifting toward the shoal. — 1 day.
- Dismounting – severing and removal of some injured vessel structures. — 2-3 days.
- Removal of spoil from the hold. — 2-3 days.
- Washing-out and removal of excessive spoil around the vessel hull. — 1 day.
- Leak sealing operations in the hold and the engine room. — 5 days.
- Pumping out and squeezing water out from the subdivisions. — 1-2 days.
- Subtending of the injured vessel off the ridge and leading it to deep water. — 1 day.
- Loading of the previously dismounted structures, filling the earlier inaccessible leaks, preparation of the vessel for towage. — 2-3 days.
- Closing down the field activities. — 1 day.
According to the preliminary assessment the total operation time exclusively of the preparatory stage and of the idle periods due to storm. — 17-21 days.
2. Operation project development and documentation approval
Development of the operation project includes analytical work based on experience of similar operations and requirements of the good seamanship practice, necessary calculations by the procedures of rescue operations, ship theory and structural mechanics of a ship on the basis of available documentation and data obtained during the examination of the object.
Approval of the operation project shall be performed on the territory and under the jurisdiction of the country, in the territory waters of which the accident occurred.
3. Preparatory stage
3.1 Completing and concentration of the rescue equipment and consumables in compliance with a List of the manpower and resources engaged.
3.2 Making mats, graving pieces, plugs and other elements for sealing the injured vessel subdivisions.
3.3 Preparation of vessels, water-removing equipment and air supply system.
3.4 Training and instructing the participants of operation.
3.5 On-site welfare support of the field activities members: rest cabins and work clothes changing cabins, fresh water, food, first aid kit, communication and alarm system.
3.6 Energy supply for operations – diesel generating sets, fuel, oil, water.
3.7 Providing of the field unit with the meteorological forecasts.
It is preferably that a marine compressor system and diesel generator sets are enabled. However, in the event of their gross failure it is necessary to provide for delivery of the equipment to the injured vessel.
4. Deployment on site
4.1 Transfer of the field unit from the base to the site.
4.2 Taking of the rescue and other equipment aboard of the injured vessel.
4.3 Setting up of the emergency lighting lines, gangways, labor saver tooling.
4.4 Equipping premises for rescuers.
4.5 Operational check of the energy supply and air pressure supply facilities.
5. Measures to be taken in order to prevent the object from drifting toward the shoal
Two restraining lines with anchors are brought from the stern of the injured vessel by means of an auxiliary water craft. Any slack of the lines shall be hauled tight.
A crane boat with a weight-carrying capacity of 30-50 ton-force is brought to the portside of the injured vessel.
A gas-cutting machine is installed. The following components and products are cut off and removed from the vessel:
- cargo cranes,
- hold hatchway covers,
- top part of fiddleys.
7. Removal of spoil from the hold
First a hole in the hold through which washing out of the hold was performed, shall be walled up.
A soil scour installation and a deep-well pump for muddy water pumping-out are put into the hold.
Soil is washed out and removed together with water until the deck is absolutely clean.
8. Removal of excessive bottom soil around the vessel hull
An assisting towboat via its screws will remove sand from around the injured vessel hull.
In places where it is necessary to provide access to the breaches the rocky soil is partially removed on outside of the vessel hull.
9. Leak sealing operations in the hold and the engine room
9.1 Breaches in the area of the hold, which are accessible from outside shall be patched up with mats from outside.
9.2 The deck breaches shall be patched up with mats from inside.
9.3 The test pumping out of water from the hold is performed with identification of the earlier not identified leaks of water and their filling.
9.4 Sealing of air and sounding pipes, hand holes and other piping systems of the double bottom and double board tanks, intended for scheduled drainage discharge, is performed.
9.5 Sealing of flats, piping system and closures of the engine room is performed.
9.6 Test blowing of tanks and the engine room is carried out with filling of the identified air leakages.
10. Pumping out and squeezing water out of the subdivisions
10.1 Undamaged partitions where water had been let in on purpose, shall be drained.
10.2 General pumping out of water from the hold is performed with total water feed of not less than 600 cubic meters per hour.
10.3 Master air blowing of the engine room with finding out and filling of air leakages is performed.
10.4 Any slack of the retaining stern lines shall be taken up constantly.
10.5 Establishing of a towing line for subtending. A tow boat for subtending is positioned.
11. Subtending of the injured vessel off the shoal and taking it out to deep water
11.1 Using an assisting towboat and retaining ropes subtend the vessel off the shoal and take it out to the water 6-7 meters deep.
11.2 Perform a diver inspection of the earlier inaccessible part of the vessel’s bottom.
11.3 Patch up the identified breaches with mats and wedges.
12. Loading of the previously dismounted structures, filling the earlier inaccessible breaches, preparation of the vessel for towage.
12.1 Using a crane boat, load the previously dismounted units and products to the hold.
12.2 Provide floatability and ship’s stability for emergency towing.
12.3 Deliver the object to the client.
13. Closing down the field activities
Equipment and personnel of the field unit shall be returned to the home base.
The operation documents shall be closed.
3. LIST OF DISCOVERED HULL DAMAGES
|No.||compartment||position||Type of damage||length, ,||length, m||width, m||height, m||sealing||water||air|
|1||hold||Portside, middle part||A crack in the deck along the board||15.0||15.0||From inside||+|
|2||id.||Portside, the after part||A hole in the deck||2.1||1.1||From inside||+|
|3||id||id||A crack in the deck||2.0||From inside||+|
|4||id||Starboard to the bow from the midship||A crack in the deck along the board||10.0||From inside||+|
|5||id||Starboard, middle part||A cross crack in the deck||1.5||From inside||+|
|7||id||id||A crack in the deck along the board||0.7||From inside||+|
|8||id||Starboard behind the midship||An aperture in the deck||1.5||1.8||From inside||+|
|9||id||id||A hole in the luff plating||2.0||1.5||From outside||+|
|10||Engine Room||Portside, the bow part||id||7.0||4.0||From outside||+|
|12||id||Portside, middle part||id||2.0||1.5||From outside||+|
|14||id||Starboard, bow part||id||2.5||From outside||+|
|15||id||Starboard, middle part||id||From outside||+|
|16||id||Both boards, around transverse frames No. 25-26||A vertical fold of the outside plating of the board that goes all the way below the bottom||From 4.0|
4. OPERATION WORK SCHEDULE
1. Preparation stage
1.1 The field operation personnel and all the necessary operation means are completed in accordance with a list of the involved workforce and means. Sheet steel is cut into workpieces with guillotine shear in advance for ease of transportation, on-site adjustment, and welding.
Some of bolt eyes, air pipe plugs, and clamps shall be made in advance.
1.2 Prepare the marine diesel generators and compressor for operation. If it is impossible to make the equipment operational, substitute mobile units with similar specifications shall be selected. They shall be examined thoroughly during the operation by measuring their oil consumption.
1.3 Check mobile tank drainage pumps according to their packages, as well as the presence of lubricant oil in the crank case. Equip with safety lines and straps.
1.4 Accommodations for the crew’s rest, change of clothes, messing, and drying of work clothes shall be prepared. Radio communication channel shall be provided and established between the vessel and the base in order to obtain weather condition forecasts and warnings.
1.5 A convenient area shall be equipped for assembling and welding of mats. A vice clamp and a construction which can be used instead of an anvil shall be available within reach.
1.6 The air blowing system of the compressor shall be assembled, fitted with hose lines, tested in operation.
1.7 Prepare depth measuring means on a utility boat and to equip the marker beacons.
Provide access to all the premises of the vessel, to lay the emergency lighting lines.
1.8 The field operation personnel shall take a briefing on the Work Plan and Operational Safety.
2. Deployment on site
It is possible that some of the actions mentioned in the previous paragraph may be transferred to this stage.
2.1 A mobile tripod-bipod stand, snatch blocks with cargo runners, mobile lever-type hand winches and deck machinery of the vessel which delivers the equipment should be used for transshipment of rescue instruments and materials to the injured vessel.
2.2 The equipment shall be sorted out and put together conveniently so that no time would be wasted later in searching for a necessary piece. Instruments that can be spoilt by wetting shall be placed in covered areas.
2.3 A utility boat shall perform updated measurements of the depth and mark with marker-beacons a passage around the hull of the injured vessel for further operations of the tow boat.
3. Securing the positioning of the object
3.1 If ropes that prevent the object from any further running aground are preserved, their fastening and condition shall be examined. The leadlines of the landfast lines shall be transferred to gypsyheads of stern wrenches and any slack of the lines shall be taken out of them.
3.2 If there are no existent lines present, new ones shall be prepared. Anchors of the injured vessel shall be un-riveted and carried out toward the deep water with one shackle of an anchor chain connected to a mooring line. Spreading of anchors shall be more than 60 m apart from each other. Any slack of anchor lines should be taken out of them with wrenches after laying-out of anchors.
4. Dismantling operations
4.1 A floating crane shall be led to the portside of the object. Deploy a flame cutoff arrangement in the fore part of the injured vessel.
4.2 A bow group of cargo hatches covers shall be dismantled and laid on the cargo deck of the floating crane or on the bottom soil. The dismantling procedure includes stropping an element, its separation from the neighbor ones, its lifting and unloading. If there is a possibility for an on-the-spot disassembling of compounds, it should be utilized. In case of any difficulties in disassembling, elements shall be separated by means of a gas burner.
4.3 A bow crane shall be dismantled in the same way.
4.4 Then a floating crane shall be moved to the after body of the object.
4.5 Dismantle an aft crane in the same way.
4.6 Dismantle an aft group of the cargo hatches covers in the same way.
4.7 Dismantle a bow ramp.
Presence of the floating crane at the object’s board shall be used to the maximum extent possible for transferring portable pumps, a hydraulic giant, materials and pieces for breach sealing to the injured vessel.
It may turn out that it will be feasible and advisable to dismantle a top part of fiddleys from an aft position of the crane.
5. Soil removal from the hold
5.1 Find, wash out, and seal a breach through which main volume of soil enters the hold by means of a mat from the outside. (According to the survey it is located on the starboard toward the stern from the midship.)
5.2 Wash out the bottom soil in the hold and pump out the mixture overboard with portable pumps. It might turn out helpful to cut an aperture in the board of the injured vessel so that not to pump over the top. A bolted steel mat with soft rubber packing shall be prepared right away for sealing of the given aperture when there is no need for it anymore.
5.3 After the final clearing of the hold from the soil and a delay for mud settling, a thorough survey of all the surface of the deck shall be performed in order to find previously undetected damages of the deck and to arrange them for sealing. Perform an adjustment of the operation plan on the basis of that survey and preparation.
6. Washing away of bottom soil around the ship hull
6.1 An auxiliary tug is arranged for washing away of the soil (sand) starting from the stern toward the bow, first along the starboard, then along the portside. If possible the tug should be trimmed toward the stern.
6.2 Control of the washing away is performed by constant measurements of the depth within an operating zone of the screws.
6.3 Positional changes of the tug are directed by mooring ropes to the injured vessel.
6.4 There is no need to work at one position for longer than 15 minutes. It is advisable to smoothly put a rudder from hard over to hard over.
7. Rocky soil removal
If it is required for operational provision of breach sealing to remove some rocky soil, it shall be performed by divers after the sand is washed away. Scope of such operations should be minimized, they should be chosen only for cases of extreme necessity.
8. Sealing of the hold
8.1 According to the preliminary plan the hold is prepared for draining by pumping the water out of it. That is why it is reasonable to seal breaches in the shell plating in the hold area from the outside, and breaches in the deck and double boards from the inside of the hold.
8.2 It is preferably to seal breaches with steel mats with soft rubber packing that are fixed to hull structures by means of T-shaped screws or adjustable clamps which are welded at an outline of a mat.
8.3 Cracks may be sealed with wedges and blocks with hemp, small holes with plugs and blocks with hemp.
8.4 On completion of the sealing operations, a testing pumping–out shall be performed for the purpose of detection of points of water entry if there are any left. Any discovered points of water entry shall also be sealed.
9. Engine Room sealing
9.1 Taking into account a large amount of destruction of the shell plating in the Engine room area and a lack of a double bottom there it is advisable to seal the Engine room for squeezing out the water by means of a pressurized air. To accomplish that it is necessary to air seal the top part of the compartment as far downward as possible. The lower the top edge of the unfilled hole is, the less water will remain in the Engine room.
9.2 All pipe lines that go from the a part of the Engine room, all ventilation tubes, cable passages through the deck and compartments, packing seals of fittings remote-control gears should be blinded off. All the valves in the Engine room of the draining, ballast, and fuel systems, and of a water extinguishing system shall be shut tightly. Batten down the sliding doors, man holes, and latchings. An oil products film on the water surface in the Engine room shall be treated with sorbents.
9.3 Check the tightness of a removable plate closing in order to replace equipment in the deck above the Engine room. Ease, pack and tighten if necessary.
9.4 Standard closings in the Engine room shaft in its main passage, doors and an emergency exit hatch shall be sealed. In case of any problem with their use, standard closings shall be cut off and replaced with soft rubber padding steel mats with bolts and pegs M20 with embedded cross beams made of a channel bar or a cross bar. Plywood mats with soft rubber padding may be used for small holes.
9.5 Measuring and air pipes of tanks located in the following compartments shall be blanked off — No. 29, 30, 33, 34, 36, 38, 39-43, 46, 50.
9.6 Testing blowing-out of the compartment shall be performed with searching and sealing of air leakage places. An air supply hose is connected to a nozzle welded to one of blank plugs of air pipes, or it is brought in by a diver from below through a not sealed breach in the bottom of the compartment.
10. Sealing of the double bottom and double board tanks
10.1 Blank off the measuring and air pipes of internal board tanks No. 16, 17, 25, 26, 27, 28, fuel tanks No. 12, 13, 14, and fresh water tanks No. 19 and 20. A flanged socket with a Du 25 pass-through valve for connection of ф vent hose shall be fitted to a pipe plug of one of air pipes of each tank. In extreme case at least tanks No. 25-28 and 19-20 shall be fitted with it.
10.2 Testing blowing-out of the sealed compartments shall be performed with searching and sealing of air leakage places.
11. Draining of flooded subdivisions
11.1 Bring drainage pumps to a forepeak and hold. Commence a general pumpage of the flooded subdivisions from the bow toward the stern.
11.2 Supply a compressed air into the double bottom and double board tanks, squeezing the water out.
11.3 Supply a compressed air for a general blowing-off of the Engine room.
11.4 Place oil retention seabooms around the vessel by the time of draining of the Engine room.
11.5 Any slack of the retaining lines shall be taken up constantly.
11.6 Establish a towing line for subtending of the object off the shoal (mooring at the bow of the injured vessel.)
Operations at that stage become uninterruptible. There shall be two shifts, which alternate work and rest every six hours.
12. Subtending of the injured vessel off the shoal and leading it to the deep water
12.1 Turning the vessel toward starboard, subtend the vessel off the shoal using the pulling of the auxiliary tug. In case of any hindrances to the subtending due to protruding areas of bottom soil, a number of turns shall be increased and they shall be combined with reversal slews and onward subtending.
12.2 Any slack of the retaining lines shall be taken up constantly.
12.3 A parallel movement of a boom defense ring to moving of the vessel shall be ensured. Upon reaching the deep water, the boom defense shall be taken aside and the water surface inside the defense shall be cleaned with a skimmer, after which booms may be taken away.
12.4 Lead the vessel out to the depth of 6-7 m. Secure its position with a tug boat and, if necessary, with relaying the anchors.
12.5 A diver inspection of a previously inaccessible part of the bottom shall be performed.
12.6 Acting upon particular circumstances, a decision on additional patching of damages shall be taken and they shall be patched. If necessary, sealing and strengthening of previously set seals shall be performed.
13. Loading of previously dismantled structures of the vessel into the hold
13.1 Load previously dismantled structures of the vessel into the hold by means of a floating crane. Hatch covers shall be laid across their width, which is 15.1 m, two covers in a row, starting with the largest ones. The loading operation shall be performed from the bow toward the stern, constantly monitoring the list and the trim of the vessel. Where necessary emergency beam supports shall be used to prevent the deck from being pressed through. The second layer shall be laid upon the first one. The covers ramp shall be placed in the stern. Dismantled cargo cranes are laid upon the covers and the ramp, as well as parts of the fiddleys.
13.2 The anchors with a shackle, if there is no requirement to return them to their place, shall also be loaded into the hold upon the hatch covers. If necessary, the floating crane will bring them to their place and clinch the chains.
13.3 Upon completion of that stage the vessel shall stay without any list with a minimal trim by the stern.
14. Completion of the field operations
14.1 Delivering the object to the client.
14.2 Taking the rescue equipment and remaining consumable materials off the injured vessel.
14.3 Field team returning to the base.
4. LIST OF INVOLVED WORKFORCE AND MEANS
- A tug boat with a hauling force on mooring lines of 30-50 ton-force and a draft of up to 4 m. — 1 unit
- A floating crane with a handling capacity of 30-50 ton-force and equipped with a cargo deck — 1 unit
- An open or a semiopen work boat — RIB with a load capacity of 0.5-1.0 ton per 6 persons — 1
If there is a need for another tug boat for delivery and moving of the floating crane – it shall also be included in this list.
Members of the salvage team
- Works Supervisor 1
- Engineer, Deputy Supervisor 1
- Electrical engineer or electrician (he’s also a pump expert) 1
- Divers: — Diving Expert 1
- Diver – Welder — Cutter 3
- Diver – Rigger 2
- Motorman 2
- Welder – Oxygen cutter 1
Total – 11-12 persons.
- Immersion type portable electric driven pump with a cable, a starter and hoses to supply 300 sq.m. per hour 3 sets
- The same for a supply of 100 sq. m. per hour 2 sets
- The same for a supply of 16-30 sq. m. per hour 1-2 sets
Air supply equipment
- Blow-off compressor with a supply of 5-6 sq. m. per minute with a pressure of up to 5-7 bars 1
- Air distributor for 6-8 users 1
- Blowing hoses – each 50-100 m long 6 (not less than)
- Hose couplings 10 pcs
- Air valves Du 25, Ru 10 10 pcs
- Long screws (1 inch) 10 pcs
Set of equipment for a complete diving station which is able to operate in an air hose mode and an autonomous mode.
- Underwater welding and cutting plant 1 set
- Overwater welding plant 1 set
- Gas-Cutting Equipment 1 set
Equipment for a bottom soil washing out
- Hydraulic giant completed with hoses and ejector 1 set
Road stead equipment
- Anchors (may be used those of the vessel) 2
- Mooring lines, polypropylene, cir. from 125 mm, 60-120 m. long 2
- Marker beacons with drag-hooks and buoy lines 8 sets
Emergency electrical equipment
- Portable MDB for 4 users 380V and 2 user 220V (lighting mains) 1
- Power cable for 70-100 kW from a diesel generator to the board – 50-70 m long. 1
- Portable lights with 50 m. cable each 3-4 sets
- Multi-meter 1
- Hand or overhead flashlights 6
- Mobile tripod-bipod stand 1 set
- Crab winch, levered, 1-3 ton-force 2 sets
- Snatch-block SWL 3 ton-force 2 pcs
- The same for 10 ton-force 1 pc
- Steel strap with handling capacity of up to 3 ton-force and length of 1.5-5 m. 6 pcs
- Polypropylene strap with handling capacity of up to 1 ton-force and a length of 2-5 m 6 pcs
- Rigging shackles SWL 3 ton-force 4 pcs
- The same for 1 ton-force 4 pcs
- The same for 0.6 ton-force 4 pcs
- The same for 0.2 ton-force 10 pcs
- Sea ladder 10 m. 2
- Seat harness 1
- Turnbuckle 5 ton-force 2
- Portable ladder, light-weighted, 3 m 1
- Cable clamps for steel cables, d. 13-17 mm 16
- Rigging 1 set
- Entrenching 1 set
- Marking 1 set
- Bench-work 1 set
- Carpenter’s 1 set
- Rigging 1 set
The bench-mark set shall include a set of perforators, a complete set of spanner wrenches, as well as a clutch, an M12 screwing die and a screwing tap.
The entrenching set shall include crowbars, jimmies and pickaxes for splitting-up of a shielding plate at points of cutting. If possible, those tools may be taken from fire racks of the injured vessel.
- Electric drill with a set of bores.
- Screw driving machine.
- Electric fret saw with spare saws.
- Cutting-off disc machine with spare discs.
- Extension cable not less than 50 m long.
5. CALCULATIONS FOR SUBTENDING THE VESSEL
- Ship sitting chart
No Loading item Mass, t. Forward draft, m. Stern draft, m 1 Bareboat 2566 1.03 3.13 2 Dismantled units 274 0.12 0.33 3 Vessel without the dismantled units 2292 0.91 2.80 4 Water in Internal Board Tanks No. 15 and 18 and leftover of 40 t. in the Engine Room 344 -0.08 +0.66 5 Case 1. A vessel with water in Internal Board Tanks No. 15 and 18 and leftover 40 t. in the Engine Room 2636 0.84 3.46 6 Water in Internal Board Tanks No. 16 and 17 and leftover of 50 t. in the hold 400 -0.04 +0.71 7 Case 2. A vessel with water in all of the above-mentioned subdivisions 3310 0.80 4.17
- Сalculation of soil bearing power for Case 1 and Case 2.
1. Case 1
Molded stern draft — 3.46 m.
Expected actual stern draft — 2.92 m (According to measurements of depth).
Loss of the stern draft — 0.54 m.
The fore-and-aft balance ratio for the given conditions — 0.27.
The soil bearing power for Хr = 17.5 m from the checkpoint equals 0.54 : 0.27 х 100 = 200 ton-force.
2. Case 2
Molded stern draft — 4.17 m.
Actual stern draft — 2.92 m.
Loss of the stern draft — 1.25 m.
The fore-and-aft balance ratio — 0.27.
The soil bearing power — 1.25 : 0.27 х 100 = 463 ton-force.
3. Сalculation of a necessary subtending force
3.1. Onward subtending
The necessary force of the onward subtending is Т = (f тр — tg α) Ra
Case 1. Т = (0.56 — 0.02) 200 = 108 ton-force.