Seamanship Techniques 2 Episode 5 pps

143Cargo and Hatchwork Cleat Canvas tarpaulin Hatch boards Ring bolt for lashing Not lower than 10″ 24″ supports every 10″ Tyzack bar Hatch coaming Hatch coaming bracket (flanged) Deck stringer vee’d and welded to coaming Freeboard deck Transverse beam Underdeck girder Underdeck transverse Deck plate of increased scantling Seam weld Corner of hatchway (at freeboard deck) Forward Underdeck girder Butt weld Queen beam Hatch coaming Locking tongue Wheels Lanyard Trackway Hatchboards Identity paint mark Queen beam King beam Beam sockets Battening bar End coaming Ring bolts (for securing hatch tents) (or locking wires) Side coaming Cleats Ring bolt Beam bolts Tyzack bar Figure 6.1 Conventional hatch. Figure 6.2 Hatchway construction detail. 144 Seamanship Techniques The cleating arrangement was such that once the tarpaulins had been tucked, battening bars (steel) would be inserted on top and secured by wooden wedges. It was important to secure the wedge correctly into the cleat, or, when hammering home, the grain could split on the edge of the cleat. Finally tarpaulins and hatch boards were secured by locking bars or locking wires over the complete hatch, to prevent the coverings from blowing adrift and as an anti-theft device. Should the vessel’s freeboard ever be lost, locking bars would also restrict the wooden hatch covers from floating adrift, an important factor should the vessel be salvaged after a sinking. Tarpaulins were always laid with their seam edge athwartships and away from the fore end of the vessel. This gave some protection from the forward prevailing weather. Tarpaulins were also marked by eyelets to indicate their newness, while hatch identity was established by the number of knots placed in the securing lashing, a useful practice when several hatch tarps were made up and stowed together. Securing the Hatch for Sea Once the cargo work has been completed, the beams positioned, and the hatch boards replaced, the three tarpaulins will be stretched in the order stated. Battening bars will then be forced between the cleats and the tucked overlap of the two tarpaulins, and secured against movement by wood wedges being hammered into the cleats. It is important that the wedge is hammered in from the correct direction, namely with the long side against the battening bar. The wedges should be hammered in by use of a wooden mallet, hammering in the direction of the grain of the wood. The flat end of the wedge is forced forward so as to be driven in by any head-on weather, as opposed to being forced out. The heavy iron locking bars are then secured across the top of the hatch, being hooked under the upper lip of the coaming and drawn together in the middle of the hatch by means of a worming screw arrangement which may be locked by a padlock. The number of pairs of locking bars to a hatch will ultimately depend on the length of the hatchway and the number of hatch board sections as per rigging plan. Each section of board should ideally be secured by at least one pair of locking bars. Hatch Tents As is often the case, when the vessel is working cargo, rain may interrupt the normal working operation. With the conventional hatch it proved a laborious task to re-cover the hatchway every time a shower stopped work, and so a tent, similar to a bell tent, was hoisted, usually from a derrick head. The base area of the tent was sufficient to cover the total hatchway area, and the tent was secured by tails to a wire stay running around the hatch coaming. This method was a simple but time-saving exercise, which prevented the cargo getting wet. The tent was easy to put in place and could be just as easily cleared. 17. Booby hatch access to hold. 145Cargo and Hatchwork With the efficient opening and closing of steel hatch covers today, tents are not required for the modern vessel. CONVENTIONAL HOLD Construction The hatchway entrance is a cut-away from the upper deck stringer plates. The corners of the hatchway are cut on the round to provide continuity of strength and prevent shearing stresses causing cracks athwartships and bending forces causing cracks in the fore and aft line. The corner turns of the hatchway are often fitted with reinforcing bars to prevent loading and racking stresses (Figure 6.2). Tank Top Ceiling This is a wooden sheathing over the double bottom tank tops, usually in way of the hatch, providing the tank tops with some protection from wear and tear. The ceiling also assists ventilation and drainage of cargoes, and with many cargoes relieves the necessity for laying of double dunnage. This wood covering may come in one of two forms – either wide flats, laid on bearers which leave space for liquids to drain off to the bilges, or set close into a composition of cement and Stockholm tar. When bulk cargoes are being regularly carried, the second method is often employed, as the drainage spaces tend to become choked when the first method is used. It is not uncommon to see the most modern vessel with no tank top ceiling at all, but in this case the tank top itself is normally protected by having increased scantlings. Turn of the bilge construction is shown in Figure 6.3. Spar Ceiling This may be in the form of horizontal or vertical wooden battens to keep cargo off the steel work of the ship’s side. Contact between the shell plate and the cargo tends to lead to excessive cargo sweat damage, and to prevent this occurrence spar ceiling, sometimes referred to as cargo battens, is secured in cleats throughout a cargo hold and ’tween deck. Limber Boards These are wooden boards similar to hatch boards that cover the bilge bays, which are situated at the bottom sides of the lower holds. These bays run the full length of the hold and should be regularly inspected for their cleanliness. The boards are supported by the tank side brackets between the floors and the frames. Bilge Suctions – Strum Box The bilge suction (Figures 6.4 and 6.5) is usually found in the aftermost bay of the hold. Vessels normally trim by the stern, so that this aft siting is best for drainage within the confines of the hatch. Scupper pipes tend Shell plating Side frame Bracket on frame Spar ceiling Tank side bracket Lightening hole Bilge area Non-return valve Strum box Margin plate Double bottom CARGO HOLD Wooden limber boards Wood ceiling Drain hole Figure 6.3 Turn of bilge construction. Figure 6.4 Bilge suction – strum box. Limber boards Margin plate Strum box Cement Non-return valve Shell plate Turn of the bilge 146 Seamanship Techniques to drain direct from the afterpart of the ’tween deck into the bay containing the strum box. A non-return valve must be fitted clear of the strum, and in the more modern vessels this valve is situated clear of the bilge area. The purpose of the non-return valve is to prevent accidental run back from the pumps, which may cause flooding in the hold. The suction end of the pipe is kept clear of obstructions by the strum box arrangement built about the pipe opening. This strum box is so constructed as to allow the passage of water but not the passage of solids, which could interfere with suction. The sides of the strum are either slotted or hinged to a framework which will allow the box itself to be dismantled for cleaning and maintenance. The whole bay containing the strum is covered by limber boards. General Cargo Vessel Deep Tanks General arrangements vary especially in the securing of the deep tank lids and the number of tanks constructed. It is normal to find deep tanks in pairs or, if situated in a large hatch, then 2 × 2 pairs, to port and starboard. They are extensively used for bulk cargoes such as grain or chemicals but very often fitted with steam heated coils for the cariage of such things as ‘Tallow’. They may also be used to take on extra ballast when the vessel is in a light condition. Hat box pumping arrangements are operated from the ship’s engine room and the lines are fitted with a blanking off fitment when required. Most systems allow for gravity filling and tanks are all fitted with air and sounding pipes (Figure 6.5). STEEL HATCH COVER The more modern type of cargo vessel will be equipped with one of the many types of steel hatch cover which are at present on the commercial market (Figure 6.6). The many advantages with this style of cover by far outweigh the disadvantages. They are fast in closing or opening, and the latest versions are so labour-saving that one man could open up all the Circulating heating coils (if fitted) Side frame Side shell plate Grating over hat box to allow passage of water Hat box Suction to engine room Figure 6.5 Deep tank suction – hat box. Rubber gasket Check wire Bull wire Hatch top wedge Lead sheave End coaming Coaming hatch stays Track Wheel guide Side dog Eccentric wheel Balancing roller Side chains Rising track Figure 6.6 Single pull steel hatch cover. 147Cargo and Hatchwork hatches of a ship in the time it takes to strip a single conventional hatch. Their structure, being of steel, is extremely strong and generally forms a flush surface in ’tween deck hatches providing ideal conditions for fork lift truck work. Steel covers may be encountered not just at the weather deck level but throughout a vessel, inclusive of ’tween decks. Hydraulic operated covers are simple in operation, but should hydraulic fluid leak at any time, cargo damage may result. The direct pull type must be operated with extreme care, and all safety checks should be observed prior to opening the chain-operated types. Steel covers are illustrated in Figures 6.6 to 6.12 and Plates 18 to 23. Opening Single Pull Macgregor Steel Hatch Cover 1. Release the side securing lugs, ensuring that they are correctly stowed in flush position with the track. 2. Clear away any hatch top wedges between hatch sections. 3. Rig the check wire to the lug of the leading hatch section and turn up the bight of the wire on to cleats or bitts. 4. Rig the bull wire so as to provide a direct pull to the winch from the leading edge of the hatch cover. 5. Complete all work on top of the hatch covers. Check that the track ways are clear of all obstructions, such as pieces of dunnage etc. Figure 6.7 Securing steel covers. Cleating (dogging) arrangement. 148 Seamanship Techniques 6. Turn down the eccentric wheels by use of bar levers, or by using the jacks under the hatch cover sections. 7. Check that the locking pins are securely replaced in the eccentric wheels once the wheels have been turned down to the track, in such a manner that they will not slip out when the wheel rotates or when the hatch is in the vertical stowed position. 8. Ensure that all personnel are aware that the hatch cover is about to open, and that the stowage bay for the covers is empty and clear to allow correct stowage of the sections. 9. Have a man standby to ease the check wire about the bitts, and, just before hauling on the bull-wire, remove the locking pins at the ends of the leading hatch section. 10. Heave away easily on the bull-wire once the locking pins are removed, taking the weight of the leading hatch section. 11. Ease out on the check wire as the bull-wire heaves the hatch open (Figure 6.6). 12. Once all hatch sections are in the stowed vertical position, the bull-wire should not be removed until the securing chains from a fixed point are in position to hold back the hatch sections in the stowage bay area. Screw cleat spanner Cross-joint cleat [manual] Eccentric wheel locking pin [secures wheel in high or low position] Eccentric wheel [manually adjusted to suit high or low positions in conjunction with jacking operation] Balancing roller spindle Jacking block Rubber Screw cleat Balancing roller Cover lifting jack [manual] Eccentric wheel turning lever [manual] Junction piece assembly Figure 6.8 Figure 6.9 Turning down eccentric wheels. Pull on lever (under or over motion depending on hatch design) Remove locking pin Insert bar Packing Trackway Remove lug Wheel free to run Remove lever Lug stowed Replace locking pin 149Cargo and Hatchwork 18. Single pull Macgregor steel hatch covers in the stowed upright position, showing fore and aft ends of two separate hatches. 19. Steel hatch cover, with the locking pin seen in the ‘out’ position. The eccentric wheels are turned down on to the trackway so as to raise the hatch. The securing pin through the eccentric wheel is clearly seen passing through at the level of the bush. Side dogs are hanging vertically down under the coaming, and lifting lugs, together with jacking- up plates, are to be observed above the eccentric wheel. 20. Chain pull steel hatch covers in the stowed upright position. 150 Seamanship Techniques 22. Hydraulic folding Macgregor steel hatch covers (weather deck), and hatchway showing a full cargo of scrap metal. 23. Open hatchway showing exposed ’tween deck space. Pontoon covers are stacked in the after end. Lower hold contains general cargo. Spar ceiling is shown exposed on the lower hold sides. 21. Rack and pinion horizontally stowed steel hatch covers. 151Cargo and Hatchwork Hinged sheave Stowing arm Wire pendant Hauling eyeplate Hinge Panel 1 Panel 2 Panel 3 Wheel Closing arm Securing hook Stowing arm pedestal Closing arm pedestal 7.8m clear opening 2.87m slowage height 23.2m deck opening 8.5m deck opening Hatch open showing typical overall dimensions to suit three rows of three 20ft containers stowed through the hatch. N.B. All dimensions given are typical and vary according to individual installations. Emergency operation can be arranged for all installations. 19.2m clear opening Figure 6.10 Direct pull weatherdeck hatch covers (above). Side rolling covers (right). Rack and pinion drive, with hydraulic lifting and cleating. Flexible hoses or electric supply with quick release coupling Wheel Link mechanism Cylinder Trailing pair Leading pair Drag link Hinges Detachable stowage rail Hydraulic pot-lift Wheel-box Optional : quick acting cleat or hydraulic cleating Self-engaging locking at transverse cross-joint Optional: hydraulic cleating or quick acting cleat Rack and pinion drive Figure 6.11(a) Steel hatch covers, ’tween deck. Trailing pair Leading pair Disconnected Fixing bolts Drag link 152 Seamanship Techniques Folding One pair external cylinder Cylinder arrangement Figure 6.11(b) Weather deck hydraulic folding hatch covers. Figure 6.12 Roll stowing covers – Rolltite. Originally designed by Ermans and under manufacture by Macgregor. 13. Clear away the check wire, coiling it down to one side of the hatch. Do not attempt to detach the check wire from the lug of the leading edge of the hatch. GENERAL CARGO TERMINOLOGY Bale Space Internal volume measured to the inside edges of the Spar ceiling, beams, tank top ceiling, and bulkhead stiffeners (spar ceiling is often referred to as cargo battens). Broken Stowage Unfilled space between packages, this tends to be greatest when large cases are stowed in the end holds, where the shape of the vessel fines off. Deadweight Cargo This cargo measures less than 40 cu.ft per ton (1.2 cu.m per tonne), and freight is paid on the actual weight. Dunnage This is material used when stowing cargo to protect it from contact with steelwork, other cargoes, or any possibly damaging influences. Tank tops are usually covered with a double layer of dunnage wood, the bottom layer running athwartships to allow drainage to bilges, and normally being more substantial than the upper layer, e.g. 2 in. × 2 in (see Figure 6.13). Additional dunnage is soft light wood, dry and free from stains, odour, nails and large splinters. New timber should be free of resin and without the smell of new wood. Materials also used for similar purpose are matting, bamboo or waterproof paper. Grain Space This is the total internal volume of the compartment, measured from the shell plating either side and from the tank top to underdeck. This measure- ment is used for any form of bulk cargo that could completely fill the space, an allowance being made for space occupied by beams and frames. Figure 6.13 Use of dunnage. Upper layer Wood laid approx. 6″ 2′ to 3′ apart 1″ Bottom layer Tank top 1″ = 2.5 cm 1′ = 30 cm [...]... mild steel welded construction Ventilators open Ventilators open 74 72 Hold temperature 66 64 Outside air (Dewpoint temperature) Ventilator shaft to hold 62 60 Figure 6 .23 58 1 Figure 6 .24 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Hold temperature and outside Dewpoint temperature graph 16 17 Cowl ventilators 160 Seamanship Techniques 4 5 6 7 8 9 10 Fire Insulation material should be non-combustible, if possible,... but for different ports by separation cloths, paint or other appropriate separation mode 153 154 Seamanship Techniques 21 22 Visiting transit shed ashore periodically to inspect stowage and correct handling of cargo Seeing that fire precautions are observed throughout cargo operations HOLD PREPARATION 1 2 3 4 5 6 7 8 9 10 The compartment should be swept clean, and all traces of the previous cargo removed... Specific gravity Cu.ft per tonne Coconut oil Palm oil Palm nut Tallow Whale oil 0. 9 25 –0.931 0. 920 –0. 926 0.9 52 0.911–0.9 15 0.880–0.884 38.8 38.9 37 .5 39.4 40.76 CONTAINER TONNAGE The container is probably the most common unit load system in operation today The introduction of standard size containers took place in the late 1 950 s, and the container trade has flourished ever since Most cargoes are shipped... anchor Exposure cover Grommet Hawser jib halyard block (secured by rolling hitch) Sea anchor Lifeboat Oil bag Tripping line Endless whip Steering oar Figure 7.10 Heaving to 176 Seamanship Techniques 23 24 25 26 27 28 29 30 31 A searchlight, capable of effectively illuminating a light coloured object at night having a width of 18 m at a distance of 180 m for a total period of 6 hours and of working continuously... refilling Figure 7.7 Thole pins 174 Seamanship Techniques Copper band (if fitted) Standard Lifeboat Equipment Leather Grip 1 Blade Figure 7.8 Shaft Loom Oar 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 Sufficient buoyant oars to make headway in calm seas Thole pins, crutches or equivalent arrangement shall be provided for each oar provided Pulling oars are normally between 3. 05 and 4 .26 m in length (10–14 ft), they... list for use) Boatwork 17 18 19 20 21 22 1 75 An efficient radar reflector One copy of the life-saving signals table, prescribed by regulation V/16 on a waterproof card or in a waterproof container Two efficient painters of a length equal to not less than twice the distance from the stowage position of the lifeboat to the waterline in the lightest sea-going condition or 15 m whichever is the greater One... measuring 40 cu.ft per ton (1 .2 cu.m per tonne) or more The standard is used for comparatively light cargo on which freight is paid on space occupied Stowage Factor The volume occupied by unit weight, this is usually expressed in cu.ft/ ton or cu.m/tonne, no account being taken of broken stowage DUTIES OF JUNIOR CARGO OFFICER 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 Usually taking responsibility... about the cargo compartment, but these are becoming increasingly rare with the more up-to-date technology 159 Figure 6 .21 Use of can hooks Sling should not be pulled from under load or the load is caused to tip Timber bearers Figure 6 .22 Use of chain slings Properties of a Good Insulating Material 1 2 3 Odour All material used should be odourless to prevent tainting of cargoes Vermin The material should... Shippers’ instructions with regard to carriage temperatures should be strictly adhered to A cargo log of these temperatures should be kept Extreme care should be taken on loading to leave enough 155 156 Seamanship Techniques ‘ullage’ for expansion of the oil during passage Overheating should never be allowed to occur, as damage to the oil will result Flour Susceptible to damage from moisture or by tainting... legs, 21 /2 ft (0.7 62 m) Canvas bag open both ends Grommet, 4″ dia Becket (100 mm) Round-mouthed sea anchor for boats less than 30′ (9 m) in length Tripping line 18 fathoms, 11/4″ manilla ( 32. 94 m × 10 mm dia.) Figure 7.9 Sea anchor Exposure cover Grommet Hawser jib halyard block (secured by rolling hitch) Sea anchor Lifeboat Oil bag Tripping line Endless whip Steering oar Figure 7.10 Heaving to 176 Seamanship . issued. 1 62 Seamanship Techniques TABLE 6.1 Cargoes carried in deep tanks Product Specific gravity Cu.ft per tonne Coconut oil 0. 9 25 –0.931 38.8 Palm oil 0. 920 –0. 926 38.9 Palm nut 0.9 52 37 .5 Tallow. temperature) °F 74 72 70 68 66 64 62 60 58 123 456 7891011 121 314 151 617 Figure 6 .24 Hold temperature and outside Dewpoint temperature graph. 160 Seamanship Techniques 4. Fire. Insulation material. plates, are to be observed above the eccentric wheel. 20 . Chain pull steel hatch covers in the stowed upright position. 150 Seamanship Techniques 22 . Hydraulic folding Macgregor steel hatch covers (weather