# Military

PART THREE

OCEAN TERMINAL OPERATIONS

CHAPTER 7

PRESTOWAGE PLANNING

Section I. Terms and Factors

7-1.   INTRODUCTION: This chapter introduces special terms and other factors which cargo handlers need to know for prestowage planning.   It discusses steps for formulating plans for loading, stowing, and discharging cargo aboard cargo vessels as well as the new T-AKR 295/296 Class ships.   Appendix A includes measurement conversion tables to aid in any necessary mathematical computations.

7-2.   VESSEL TONNAGE TERMS. Every cargo vessel has two inherent physical limitations which planners must consider in planning cargo loading: the volume and the weight of cargo it can carry.   The cargo planner must understand volume and weight terms related to the vessel and its cargo.

a.   Volume or Space Tons. Volume or space tons express measurement of volume used in ocean shipping.

(1) A measurement ton is a measure of the space occupied by cargo, expressed in units of 40 cubic feet.   To determine the number of measurement tons of cargo, cargo planners multiply height by length by width and divide the results by 40.

(2) A displacement ton is a unit of measure equal to the volume of one long ton of seawater (35 cubic feet).   It is used in determining the displacement of vessels.

b.   Weight Tons. Weight tons express measurements of weight.

(1) LTON-2,240 pounds.

(2) STON-2,000 pounds.

(3) MTON-2,204.6 pounds.

(4) Measurement ton-40 cubic feet.

c.   Tonnages. Weight and volume tons when applied to vessels are expressed as volume or space tonnage, displacement tonnage, dead weight tonnage, and cargo dead weight tonnage.

(1) Volume or space tonnage consists of gross and net tonnage.

(a) Gross tonnage is the internal cubic capacity of the vessel expressed in gross tons.   It is also called gross registered tonnage.   One hundred cubic feet equals one gross ton.

(b) Net tonnage is the tonnage remaining after deducting from the gross tonnage all nonrevenue-producing space taken by the boilers, engines, shaft alleys, steering apparatus, chain lockers, charthouse, crew quarters, and so forth.

(2) Displacement tonnage is measured in two ways.

(a) Displacement loaded is the weight in LTONs of the entire ship--the vessel itself, fuel, water, stores, dunnage, crew, and cargo.

(b) Displacement light is the weight in LTONs of the vessel less cargo, passengers, fuel, water, stores, dunnage, ballast (fixed and temporary), crew, and cargo.

(3) Dead weight tonnage is the total weight-carrying capacity of a vessel, or the difference between displacement light and displacement loaded, expressed in LTONs.   It includes the weight of fuel, water, stores, dunnage, ballast, crew, and cargo.

(4) Cargo dead weight tonnage is the actual payload of the vessel.   It is obtained by deducting the weight of fuel, water, stores, subsistence, dunnage, ballast, and crew from the dead weight tonnage.

d.   Bale Cubic Capacity. Bale cubic capacity is the space available for loading cargo measured in cubic feet extending to the inside of the cargo battens on the frames and to the underside of the beams.   This measurement is used to compute the space available for general cargo.

e.   Grain Cubic Capacity. Grain cubic capacity is the maximum space available for cargo.   It is measured in cubic feet from the inside of the shell plating to the underside of the deck plating.   This measurement is used for computing cubic space available for loading bulk commodities.

7-3.   STOWAGE PLANNING FACTORS. The amount of cargo that can be placed in a vessel will vary according to the skill and compactness with which it is stowed.   The following factors help to determine the space available in the vessel for cargo, the amount of cargo that can be stowed, and the most economical use of space.

a.   Broken Stowage. Broken stowage is lost cargo space in the holds of a vessel due to the contour of the hull and/or the shape of the cargo and prestowage methods.   Dunnage, ladders, and stanchions are examples of broken stowage.   Broken stowage is shown as a percentage figure which is an estimation of the space that will be lost.   The percentage factor will be applied to the cargo or the ship's space.

b.   Stowage Factors. The stowage factor is the relation of cube (cargo or space) to weight (cargo).   Three stowage factors used in vessel cargo planning are as follows:

(1) Cargo stowage factor denotes the number of cubic feet of space required to stow 1 LTON of a specific commodity.   For lots of 1 LTON or more, planners obtain this factor by dividing the cubic measurement in feet by the weight in LTONs.   For example, given 49,610 cubic feet of C rations weighing 800 LTONs, a stowage factor of 62.01 or 62 is obtained by dividing 49,610 by 800.   For lots weighing less than 1 LTON, the cubic measurement in feet is divided by the weight of the cargo in pounds and multiplied by 2,240.   Thus, if 1,120 pounds of a specific cargo occupies 31 cubic feet, the stowage factor is 62 as shown in the example:

(2) VSF is a number that represents the relationship between cargo dead weight tonnage and space available for stowing that cargo below deck.   Planners determine the VSF by dividing the space available below deck for loading cargo (expressed in cubic feet) by the weight of the cargo to be loaded below deck (expressed in LTONs).   The VSF is then used to allocate tonnage to be loaded in each compartment.

(3) CSF is a number that expresses the relationship between the LTONs of cargo allocated to a compartment and the cubic space within that compartment, less an allowance for broken stowage.   The CSF is obtained by subtracting broken stowage from the cubic capacity of the compartment, and then dividing the LTONs allocated to the compartment into the remaining space.   Although the VSF is used to determine basic tonnages going to each compartment, the CSF helps determine the commodities that can be used to fill those tonnage allocations.   For example, compartments with a low CSF (high broken stowage) will tend to be filled with high density items.

c.   Free Space. Free space is the space in the hold that is available for additional cargo after loading has been completed.

d.   Full and Down. A vessel is said to be full and down when all the available cubic capacity has been used (full) and sufficient weight is aboard to submerge the vessel to its legal loadline (down).   All the weightlifting and cubic capacities of the vessel will then have been used.

e.   Draft. Draft is the vertical distance measured from the keel (lowest part of the hull) to the waterline.

f.   Draft Marks. Draft marks (Figure 7-1) are numbers placed on the bow and stern to indicate the amount of water a vessel draws.   These numbers are 6 inches high and 6 inches apart.   They are center-punched and painted as closely to the bow and stern as possible, using white against a dark hull or black against a white or gray hull.

(1) The figure shows that the foot mark is at the bottom of the numeral.   Thus, when the waterline strikes the bottom of the numeral 3, the reading is 3 feet even; when it strikes the center of the 3, the reading is 3 feet 3 inches (written as 3'-03"); and when it strikes the top of the 3, the reading is 3 feet 6 inches (written as 3'-06").

(2) Draft readings must be taken immediately upon arrival in port.   Personnel will insert sailing and arrival drafts in the log.   Draft readings must also be taken before and after receiving fuel, after the loading or discharging of cargo, or after any other great change in weight.

(3) A ship's officer must take the vessel's draft at 0700 and 1700 when the ship is alongside the wharf.   This reading indicates the effect of cargo being taken aboard on the ship's trim and shows the amount of fuel and water consumed.

Figure 7-1.   Draft marks

g.   Mean Draft. Mean draft is the average of the drafts measured at bow and stern.   For example, if the draft forward is 26 feet and the draft aft is 27 feet 6 inches, the sum of the two readings is 53 feet 6 inches.   Dividing the sum by 2 gives a mean draft of 26 feet and 9 inches.

h.   Freeboard. Freeboard is the measured distance from the upper edge of the main deck line amidships to the water.

i.   Trim. Trim describes the position of a ship in relation to the still water level when viewed from broadside.   The technical meaning of the term is the difference between the drafts of water at the forward and aft perpendiculars.   Trim is a matter of great concern to the master of the vessel.

(1) After the fuel, water, and stores are taken aboard, the distribution of the cargo governs the trim of the vessel.   In instances of late arrival of cargo, it may be difficult to keep the vessel in proper trim.   In such cases it may be necessary to load water ballast in the fore or aft peak, whichever is required to provide the necessary trim.   It is essential to periodically check the vessel's draft during loading operations so personnel can alter the distribution of weight before the ship gets completely out of trim. The draft should be checked after the fuel oil, cargo, and water are taken aboard.

(2) The usual trim requested by masters of cargo vessels is from 2 to 6 feet by the stern.   The vessel's draft will be 2 to 6 feet greater aft than forward.

j.   Down by the Head. This is a situation in which a vessel's draft forward is deeper than its draft aft.

k.   Down by the Stern. This is a situation in which a vessel's draft aft is deeper than its draft forward.

l.   Sagging. Sagging describes the condition of a ship that is loaded heavier amidships than it is forward and aft.   This is true especially when the bow and stern are supported by seas while its amidships are in a trough.   The tendency of the vessel to arch down or sag result in a bending movement which stresses the top members of the vessel in compression and the bottom members in tension.

m.   Hogging. The reverse of sagging, hogging is the tendency of a ship to arch up amidships as the result of too much weight at the ends and not enough amidships.

n.   List. A vessel has a list when one side of the vessel is higher than the other with respect to the longitudinal centerline.   The amount of list is expressed in degrees measured vertically by an instrument called a clinometer.   The list of a vessel is described as being to port or to starboard, according to which side is the lower side.   The ship's officers and those in charge of cargo activities should know the reasons for a vessel listing while it is being loaded or discharged so they can ensure that immediate corrective steps are taken.   In many instances, the list is caused by unequal distribution of fuel oil or water during the loading.   The most serious cause of a list is uneven distribution of cargo.   Personnel must ensure that the distribution of cargo in the vessel is not causing a list.

o.   Stability. Stability is the tendency of a ship to return to its original position after it has been displaced.   A ship has both longitudinal and transverse stability.   Longitudinal stability may be obtained by evenly distributing weight through the length of the ship.   Fairly good transverse stability may be obtained on some types of ships by placing two-thirds of the cargo (by weight) in the lower holds and one-third in the between decks.   The planner who understands the fundamental principle of stability can load a ship with nearly perfect stability.

p.   Special Markings. There are three special markings for vessels.   These three markings are listed below.

(1) Plimsoll mark. The Plimsoll mark is the safe-load mark for the vessel, according to season and geographical location.   The marking is a disk 12 inches in diameter, intersected by a horizontal line 18 inches long and 1 inch wide, the upper edge of which passes through the center of the disk (Figure 7-2).   The disk is located amidship on each side below the deck line and, in addition to being painted, is center-punched in the hull.

(2) Loadline. The loadline and Plimsoll marks are placed amidships on both sides of the hull of a vessel to denote the maximum mean draft to which a vessel may be lawfully submerged for a particular voyage, depending on the area to be traveled and the season of the year.   Figure 7-2 illustrates the loadlines found on American oceangoing cargo vessels.   Loadline markings are used with the Plimsoll mark to indicate the maximum permissible draft of the ship in different circumstances and seasons.   They are horizontal, 9 inches long and 1 inch wide, and extend from, and at right angles to, a vertical line etched 21 inches forward of the loadline disk (Figure 7-2).

(a) The summer loadline is indicated by the upper edge of line marked S.

(b) The winter loadline is indicated by the upper edge of line marked W.

(c) The winter North Atlantic loadline is indicated by the upper edge of a line marked WNA

(d) The tropical loadline is indicated by the upper edge of a line marked T.

(e) The freshwater loadline in summer is marked by the upper edge of a line marked F.   The difference between the freshwater loadline in summer and the summer loadline is the allowance made for loading in freshwater at the other loadlines.   The tropical freshwater loadline is indicated by the upper edge of a line marked TF.   This provision for deeper loading in freshwater is not applicable to the Great Lakes.

(3) Main deckline. The main deckline mark is a line 12 inches long and 1 inch wide located on each side of the hull amidships directly opposite the main deck plating and directly over the loadline.

7-4.   STABILlTY. Stability is a critical factor on vessels.   For proper stability, personnel should load a vessel to produce easy rolling, neither too fast nor too slow.   Personnel must ensure that the vessel does not carry excessive deckloads that could make it top-heavy.

7-5. STOWAGE AND CAPACITY BOOKLET. Stowage and capacity booklets are published by the US Maritime Administration for various vessel designs and contain information on the following:

• Hatch size.
• Weight limitations per square foot.
• Cargo boom capacity.
• Vessel capacities (bale cubic, grain cubic, fuel, water, and stores).
• Trim table.
• Deck plans.

If a stowage and capacity booklet is not available for the ship being loaded, the information listed previously may be obtained from the local representative of the MSC or from the vessel itself if the situation warrants.

7-6.   VESSEL DEAD WEIGHT SCALE. The cargo planner should know the dead weight tonnage of the vessel before planning the loading.   Dead weight tonnage is determined by using the vessel dead weight scale.   A particular vessel's dead weight scale gives the dead weight and displacement tonnages and the effects these tonnages have on the mean draft.   The dead weight scale is made up of four columns (Figure 7-3).

• Column A (dead weight ton-saltwater) gives the lift capacity of the vessel.   It shows the number of tons that may be carried in the vessel, including fuel, stores, ballast, water, dunnage, cargo, and so forth.   This figure does not include machinery or equipment necessary for the operation of the vessel.
• Column B (draft [feet] to bottom of keel) shows the mean draft in feet and inches.   This scale is graduated from the minimum draft of 8 feet to a maximum of 29 feet.   The maximum legal draft to which this particular vessel may be loaded is 28 feet 6 3/4 inches.   This figure is based on the legal loadline in summer saltwater.
• Column C (displacement tons, saltwater) gives the displacement tonnage of the ship plus any material placed in the vessel.
• Column D (tons per inch immersion) denotes the number of LTONs required to change the mean draft of the vessel 1 inch at various drafts.

a.   Cargo planners use the dead weight scale to determine what the draft of the vessel will be after a given number of tons have been loaded.   Using the dead weight scale shown in Figure 7-3, and using the Victory ship as an example, it can be determined that the vessel loaded with 9,000 LTONs including fuel, water, store, and cargo has a mean draft of 25 feet 4 1/2 inches at the beginning of the voyage.   Figuring 50 LTONs of fuel, water, and stores used per day at sea, the vessel used 500 tons in a period of 10 days, thus reducing the mean draft to 24 feet 6 inches.   From the dead weight scale, the cargo planner can estimate the draft of the vessel at the completion of the trip, and know whether the draft is acceptable for the harbor where the vessel will be discharged.

 Long Tons Stores 340 Fuel Oil 1,700 Fresh Water 240 Dunnage 100 Total operating supplies 2,380

The maximum dead weight tonnage (10,805 LTONs) minus operating supplies (2,380) equals 8,425 CDWT, the LTONs that may be loaded aboard the vessel.

Figure 7-3.   Vessel dead weight scale

7-7.   WEIGHT DISTRIBUTION. Cargo planners prorate the weight of the cargo to be loaded throughout the cargo compartments.   Tonnage will be distributed so that no undue strain is placed on any one part of the vessel.

a.   Vessel Stowage Factor. An efficient method used to determine distribution is the VSF.   The VSF, an important measurement in cargo stowage, is usually stated as the number of cubic feet that one LTON (2,240 pounds) of particular lot of cargo will occupy when properly stowed and dunnaged in the ship's hold.

NOTE: Cargo with a stowage factor of more than 40 is called measurement freight; cargo with a stowage factor of or below 40 is called dead weight freight.

To find the VSF, the bale cubic capacity noted in the stowage plan is divided by the CDWT.   For example, assume that all cargo will be stowed below deck in a vessel having a bale cubic capacity of 456,525 cubic feet and a cargo carrying capacity of 8,425 LTONs.   This results in a vessel stowage factor of 54.2.   If only 7,430 LTONs are allocated, the bale cubic capacity of the vessel (456,525 cubic feet) divided by the weight of the cargo available for loading (7,430 LTONs) results in a VSF of 61.4.   The cubic capacity of each compartment is then divided by the VSF to determine the number of tons to be planned for each compartment.

b.   Compartment Stowage Factor. To find the compartment stowage factor, the bale cube taken from the stowage plan is noted and 10 percent of this figure is deducted as broken stowage.   This results in a remaining space figure.   The remaining space figure is divided by proposed tonnage.   This result is rounded off to the nearest whole number and is the CSF.

7-8.   TRIM TABLE. The trim of a vessel is the difference of the forward and aft draft.   Trim is largely dependent upon the stowage of cargo.   Most shipmasters prefer the stern to be from 2 to 6 feet deeper in the water than the bow.   The term drag refers to this condition.

a.   If a drag or a trim other than that obtained by using the VSF is desired, users should use the ship's trim table.   Figure 7-4, shows the profile of a victory ship, and directly below the profile is the ship's trim table.   The purpose of this diagram is to give an approximate indication of the plus or minus changes in draft (in inches) that will occur as the result of adding a 100-ton load at any selected location on the ship.

NOTE: In this chapter, the Victory ship is used as a model for formulas and tables.   Although the Victory ship is seldom used, the Reserve Fleet contains many of these vessels.   If there is ever a war, these ships may be called into active duty and personnel will need to know how to load and discharge them.   The steps and procedures are the same for all break-bulk vessels.

b.   The trim table directly below the ship's profile in Figure 7-4 shows two scales, the upper one marked "28-foot draft" and the lower one marked "20-foot draft." The 20-foot scale is used for mean drafts up to 24 feet; the 28-foot scale is used for drafts over 24 feet.   The scale closest to the vessel's mean draft should be used.

(1) Assume that 200 LTONs are to be loaded in hold number 2 and that the weight will be distributed evenly throughout the hold.   The draft before loading is 18 feet 6 inches forward and 23 feet 4 inches aft.   Since the mean draft is less than 24 feet, the correction figure directly under the center of the hold on the 20-foot scale is used.   The forward draft will increase +7.2 inches, and the aft draft will decrease -3.2 inches for each 100 tons loaded in this location.   When the corrections are multiplied by 2 (since 200 tons are to be loaded), it indicates that the bow will sink +14.4 inches and the stern will rise -6.4 inches.   This will cause the draft to change to 19 feet 8.4 inches forward and 22 feet 9.6 inches aft.

Figure 7-4.   Maximum permissible unit deck loads in cargo spaces

(2) If the 200 tons were placed in the forward end of the hold, the correction figures directly under that location should be used.   The change in draft can be determined in the same manner as in (1) above.

NOTE: Personnel take trim factors directly under the center of the hold or compartment in which cargo is stowed.

c.   To maintain the proper trim during loading, personnel should check the forward and aft drafts periodically.

Figure 7-4.   Maximum permissible unit deck loads in cargo spaces (continued)

Section II.   Steps in Prestow Planning

7-9. OVERALL CARGO LOAD PLANNING. Once the cargo planner is notified that a vessel is to be loaded, he begins to formulate a plan for loading the vessel.   A prestowage plan is never firm, and it is frequently necessary to change it.   However, having a prestowage plan helps expedite cargo loading and helps ensure maximum use of the vessel's dead weight carrying capacity.   Planning for the vessel loading is listed below.

a.   Obtaining Vessel Characteristics. Apply the procedures below to obtain vessel characteristics.

(1) When preparing the cargo loading plan the cargo planner first obtains the following information pertinent to the particular cargo vessel to be loaded:

(a) Type of vessel: Victory Ship, design VC2-S-AP2.

(b) Number of hatches: five.

(c) Capacity and location of cargo booms: 5-ton-all hatches, 30-ton-number 4 hatch, 50-ton-number 3 hatch.

(d) Bale cubic capacity: 456,525 cubic feet.

(e) Dead weight tonnage: 10,805 LTONs.

NOTE: Cargo planners must be familiar with the discharge capabilities of all the ports of discharge at which cargo must be loaded and unloaded.

(f) Weight of fuel, water, stores, dunnage, and so forth: 2,380 LTONs.

(g) Cargo dead weight tonnage (vessel dead weight less fuel, stores, and so forth): 8,425 LTONs (see paragraph 7-6 for detailed computation).

(h) Estimated deck cargo space: 8,000 square feet (approximate).

(i) Seasonal load draft: summer saltwater-28 feet 6 3/4 inches.

(2) The foregoing information can be obtained from three sources:

(a) Stowage and Capacity Booklets, published by the US Maritime Commission for the particular designs involved (see paragraph 7-5).

(b) The local MSC representative.

(c) The vessel itself.

b.   Using Cargo Data. Table 7-1, shows a typical cargo list for a Victory vessel which provides data to be compared with vessel capacity data.   The following is a comparison of the below-deck vessel capacities listed in (d) through (i) above with the total cargo being stowed below deck, as presented in Table 7-1.

 Long  tons Cubic  feet Vessel capacity 8,425 456,525 Allowance for broken stowage ____ -45,652 Below-deck capacity 8,425 410,873 Cargo allocated for loading below deck -7,074 -410,022 Below-deck capacity not used 1,351 851

c.   Determining VSF. The VSF is determined by dividing the bale cubic capacity of the vessel (456,525 cubic feet) by the weight of the cargo to be loaded below deck (7,074 LTONs), which in this case gives a VSF of 64.5.   The VSF used to distribute weight below deck would be VSF 65 (paragraph 7-7a).

d.   Making Initial Cargo Allocation. Cargo in LTONs is initially allocated to compartments below deck by dividing the cubic capacity of each compartment by the VSF as shown in Table 7-2.   The example of a weight distribution plan in Figure 7-5 shows where cargo tonnages are allocated.   In this example, the plan is to place nine 3/4-ton trucks (24 loaded trim (L/T)) in hatch number 2, nine 3/4-ton trucks (24 L/T) in hatch number 5, eight 2 1/2-ton trucks (49 L/T) in hatch number 3, and eight 2 1/2-ton trucks (49 L/T) in hatch number 4.

e.   Determining the Vessel's Trim. To ensure that the distribution of weight as indicated in Figure 7-5 will give the proper drag, planners use a trim table to estimate the loaded trim.   Table 7-3, shows an example of a portion of a trim table.   The method used here for estimating trim assumes that all fuel, water, and stores necessary for this voyage are on board when the vessel arrives.   The arrival draft is 9 feet forward and 18 feet 8 inches aft.   If additional fuel, water, and stores are required before sailing, their weight and location should be included when estimating the loaded trim. (See paragraph 7-8.)

f.   Preparing a Prestowage Plan. Cargo handlers must prepare a plan showing where the cargo will be loaded.   Figure 7-6, shows an example of a completed prestowage plan.   This prestowage plan (also called the loading plan) is tentative and will be changed several times before or during actual loading.   The prestowage plan must be prepared before any cargo is loaded.   It should show cargo distributed throughout the cargo compartments in a manner which prevents undue strain on any portion of the vessel.   Cargo handlers should stow cargo so that the vessel will be stable and correctly trimmed.   The prestowage plan provides a basis for scheduling the arrival of cargo shipside according to priority and for estimating requirements for cargo-handling equipment.

Table 7-1.   Cargo list

 Below deck Cargo Amount Supply class Commodity Weight(longtons) Cubicfeet Cargostowagefactor Measurementtons 28, 846 cases 6,996 cases 950 bags 3,816 drums 1,300 pallets 11,628 cases 3,212 pieces 8 each 8 each 1,500 boxes 5,000 boxes 5,000 boxes 300 boxes 1,800 boxes 110 crates 20,376 cases 525 boxes CL I CL I CL I CL III CL I CL II CL IV CL VII CL VII CL IX CL II CL VIII CL IX CL II AF CL VI NAVY C rations Powdered eggs Flour Diesel fuel Palletized subsistence Clothing Steel plate Trk, cargo, 2 1/2-ton, M35A2 WWN Tk, M60A1 Repair parts Publications and forms Miscellaneous supplies Marine repair parts Miscellaneous supplies Aircraft parts Beer General cargo 666 147 64 922 1,508 223 1,050 49 349 417 307 320 270 180 87 373 145 40,961 12,594 3,006 45,472 90,980 29,070 10,480 9,878 26,954 22,285 17,806 26,880 26,250 7,500 10,700 20,376 8,830 62 86 47 49 60 130 10 201 77 53 58 84 97 42 123 55 61 1,024 314.9 75.1 1,136.8 2,274.5 726.8 262 246.9 673.7 557.1 445.2 672 656.3 187.5 267.5 509.4 220.8 Total cargo below deck 7,074 410,022 58 10,250.5 Deck cargo 16 each 18 each CL VII CL VII Trk, cargo, 2 1/2-ton, 6X6, M34 Trk, cargo, 3/4-ton, M37B1 WWN 98 40 19,756 9,628 201 200 493.9 240.7 Total deck cargo 138 29,384 734.6 Total cargo 7,212 439,406 10,985.1

(1) Analysis of cargo. Of the commodities listed in Table 7-1, the types requiring special attention are listed below.

(a) Heavy lifts. This cargo consists of 8 M60A1 tanks (43.5 LTONs each), and 24 M3582 2 1/2-ton, 6x6 cargo trucks (6.1 LTONs each).   A 50-ton jumbo boom located forward at batch number 3 can handle the tanks.   Since the two sets of 5-ton booms located forward and aft at hatches 3 and 4 can be double rigged, the trucks can be handled at these hatches without the jumbo booms.

(b) Weight cargo or bottom cargo. This cargo is suitable for bottom stowage in the lower holds or between decks.   As a rule, the stowage factor of weight cargo is lower than the VSF.   The items and respective dimensions listed below are examples of weight cargo.

 Longtons Cubicfeet Cargostowage factor Steel plates 1,050 10,480 10 Diesel fuel 922 45,472 49 Miscellaneous supplies 180 7,500 42 Repair parts 417 22,285 53 Palletized subsistence 1,508 90,980 60

(c) Filler cargo. Filler cargo is normally used to prevent or help reduce broken stowage during transport.   It consists of small durable packages or pieces of cargo that may be stowed in the spaces between larger pieces.   Filler is also the term applied to small cargo used to reduce the space above larger packages where headroom is restricted or where space is irregular and limited.   Small packages used to fill the space between larger pieces must not be subjected to undue pressure, dragging, or possible damage.   Dunnage and blocking material should be used to prevent this type of damage.   Examples of filler cargo could include rubber tires, roofing paper, baled clothing, and items of this nature.

Table 7-2.   Weight distribution

 Hold Cargo compartments Capacities (cubic feet)1 Vessel stowage factor Tons allocated No. 1 Forecastle deck Tween deck Lower deck 22,045 23,785 27,910 64.5 64.5 64.5 339 369 431 No. 2 Upper tween deck Tween deck Lower hold 27,010 21,805 27,945 64.5 64.5 64.5 417 337 431 No. 3 Upper tween deck Tween deck Lower hold 45,555 37,795 52,840 64.5 64.5 64.5 700 589 844 No. 4 Tween deck Lower hold 49,200 51,100 64.5 64.5 699 838 No. 5 Tween deck Lower hold 43,630 25,905 64.5 64.5 674 406 Total 456,525 7,074

1 The capacities of the various compartments are found in the capacity tables for the particular vessel being loaded.

Figure 7-5.   Weight distribution plan

Table 7-3.   Estimating trim
(20-foot table)

 Draft Arrival 9 ft forward, 18 ft 8 in aft, 13 ft 10 in mean (from fig 2-23) Immersion 15 ft 5 in forward, 9 ft 8 in aft Sailing 24 ft 5 in forward, 28 ft 4 in aft, 26 ft 5 in mean Drag on sailing 3 ft 11 in

Figure 7-6.   Cargo prestowage plan

(2) Specific allocation of cargo. Using the data found in a weight distribution plan and the cubic capacities of the compartments, personnel can allocate cargo to specific compartments according the guidelines listed below.

(a) Deduct allowance for broken stowage from each compartment.   In the example in Figure 7-5, 10 percent is used.

(b) Allocate cargo by weight and cubic capacity to ensure that maximum space is used.

(c) When possible, stow like items together to reduce delay in discharging and error in checking.

(d) Place heavy lifts within reach of the heavy lift or jumbo booms, except when the discharging port will furnish equipment for discharging heavy lifts.

(e) Keep items of other services (Navy, Air Force) together if possible.

(f) Stow items requiring special handling such as mail, post exchange, or security cargo, in a safe place.

(g) Personnel must not exceed the weight limitations per square foot.

(3) Compartment stowage factor. In Table 7- 1, cargo was allocated to each compartment using the VSF (65).   This factor does not make an allowance for broken stowage; the CSF is used for this purpose.   To find the CSF, the allowance for broken stowage (10 percent in this example) is subtracted from the cubic volume of each compartment and the difference divided by the weight allocated to it (Table 7-2).   Another method is to deduct 10 percent from the VSF, which in this case produces a compartment stowage factor of 58.

(a) In loading general cargo, the cargo stowage factors will differ widely, and personnel will need to load more than one commodity in a compartment to obtain the proper ratio between weight and space.   Heavy lift cargo should be placed in a location where the jumbo boom can be used.   The weight, or bottom cargo, should then be distributed in the hold of the vessel.

(b) The cargo stowage factor is used to allocate general cargo to compartments.   To determine the space required to load several commodities in one compartment, cargo handlers should multiply the weight in tons of each commodity by its stowage factor.

(c) If there is still space in the compartment for additional cargo, cargo planners may use the "topping-off formula" to fill the unused space.   This formula is used with two commodities.   One commodity has a larger and one commodity has a smaller stowage factor than that of the space to be filled.   The number of long tons of the less dense commodity to be stowed (the commodity having the higher stowage factor) is determined from the formula below.

where:

X = long tons of the less dense commodity to be stowed
V = net cubic capacity of the space to be filled (considering broken stowage)
A = stowage factor of the denser commodity
T = tonnage allocated to the space to be filled
B = stowage factor of the less dense commodity

For example, if:

V = 22,030 cubic feet
A = 30
T = 475 LTONs
B = 55

then:

= 311 LTONs of the less dense commodity

The remaining space will be filled with 164 LTONs of the denser commodity.

(4) Adjusted trim. The weights shown in Figure 7-6 do not coincide with the weights shown in Figure 7-5 because of the physical characteristics of the cargo.   Using the trim table (Figure 7-4) and the estimated trim table (Table 7-3), the drag is adjusted to reflect the new distribution of weight.   In this case, the drag is decreased by 1 inch; it is now 3 feet 10 inches.

(5) Cubic capacity maximization. When allocating cargo to ensure maximum use of the cubic capacity of the compartment, cargo handlers must consider the size of the cargo, the size of the hatches, and the overhead clearance.   This is illustrated by an analysis of number 4 hold in Figure 7-6.   The cargo planner allocated enough steel plates and C rations to build a level floor of cargo 3 feet 6 inches high.   The planner allowed 4 additional inches for dunnage and stowed the eight cargo trucks on top of this floor, putting four trucks in the aft end of the hatch and two in each wing.   The trucks were secured, and baled clothing was stowed in the trucks.   Bulkheads were then built on the inboard sides of the trucks in the wings and forward of the trucks in the aft end.   General supplies were stowed in the remaining space on top of the dunnage and topped off with the remainder of the baled clothing.   Number 4 hold has 10 feet 10 inches clearance, 3 feet 6 inches of cargo, and 4 inches of dunnage, pus 6 feet 10 inches of cargo; uses 10 feet 8 inches of this clearance; and makes maximum use of the cubic capacity of the compartment.

NOTE: Data and capacities cited and assumptions made in this paragraph are for a standard five-hatch Victory ship.

7-10. DELIVERING CARGO TO SHIPSIDE. Efficient pier operation requires the continuous movement of cargo.   Bottlenecks created by wharves filled to capacity or badly congested with loaded vehicles seriously retard the loading of vessels and reduce port efficiency.   In most instances, poor prior planning is the reason for this problem.

a.   Cargo is normally delivered to the port by railroad cars, lighters, and trucks.   Heavy-lift cargo is scheduled for delivery at a specified time and place to effectively coordinate the use of heavy lift gear.

b.   After the date and hour have been determined for the vessel to start loading, the bottom cargo is called forward before the vessel is ready to start loading.   Filler cargo is also assembled on the pier to be used as needed.

7-11.   FACILITY REQUIREMENTS (T-AKR 295/296 CLASS SHIPS). Determining pier requirements such as the required staging area, vehicle traffic patterns, and pier capacities (length, water depth, etc.) in relation to the ship's external ramp and crane configurations is of utmost importance.   The size and capabilities of the T-AKR 295/296 Class ships require that when selecting a SPOE or SPOD, it is necessary to consider whether: 1) the ship can negotiate the appropriate channels or basins, 2) the pier side depth can accommodate a fully loaded ship considering the tidal variations, 3) the pier is long and strong enough for maximum simultaneous cargo operations, and 4) vehicle staging areas are available.   Also consideration as to the availability of pier side services such as cranes should be investigated.   Generally, the use of pier cranes is faster and more efficient than the ship's crane.

7-12.   LOADING TIME. Port speed in handling break-bulk cargo varies as much as 25 to 30 percent.   Within ports themselves one section may perform as much as 20 percent more efficiently than another.   Personnel must be familiar with the labor productivity in a locality to estimate loading time accurately.

a.   If cargo were equally distributed in each hold, and tons handled per hour for all commodities were constant, estimating the working time would be relatively easy and accurate.   However, these ideal conditions do not exist.

(1) The standard five-hatch Victory vessel in this example has the following weight distribution in LTONs:

 Hatch Number 1 1,139 Hatch Number 2 1,209 Hatch Number 3 2,182 Hatch Number 4 1,586 Hatch Number 5 1,104

LTONs of cargo to be loaded in a hatch

Example (information from Table 7-4, and Table 7-5, number 1 hatch):

373 LTONs of beer = 18.65 hours x 60 minutes
LTONs per hour

b.   Cargo handlers should consider the factors below:

• Time required for rigging and rerigging.
• Time required for handling dunnage.
• Time required for blocking and lashing.
• Time required for opening and closing hatches.
• Time required for shifting the vessel or lighters (if necessary).

c.   Using the loading rates in Table 7-4, cargo handlers can calculate the loading time as shown in Table 7-5, and Table 7-6.

 Commodity Long tons per hatch season hour Tanks, M60A1 Trucks, 3/4-ton Trucks, 2 1/2-ton General cargo C rations Beer Palletized subsistence Steel plate Powdered eggs Baled clothing Drummed fuel oil Flour 90 25 25 15 20 20 25 10 10 9 20 20

d.   Cargo handlers can make certain conclusions based on the results of the calculations.   Hold number 2 will be the long hatch because it required more hours to complete than the others.   Hold number 4 will be the short hatch.   Labor gangs can be scheduled so that all hatches will be completed at about the same time.   Supervisors should make constant checks during loading to prevent delays and to ensure that the planned tonnages are actually being loaded.

e.   The times given in Tables 7-5 and 7-6 apply to the time required to load the vessel.   Delays caused by equipment breakdown, foul weather conditions, and failure of cargo to arrive as scheduled should be added to the predicted loading time.   If the hatches must be closed and opened again between shifts, the estimated time must be increased accordingly.

LO/LO cargo should be staged in its own area, separate from RO/RO cargo, and should be separated by which crane resource will load it.   Likewise, cargo within each staging area should be grouped according to its final stow location (deck and hold).   This should be possible due to the specific assignment of cargo holds to a particular external loading ramp and crane resource.

initial calculations

 or 4,525 = 75 hours 25 minutes    60

No. 2 hatch
(one hatch section)

 or 4,778 = 79 hours 48 minutes    60

initial calculations (continued)

 or 4,366 = 72 hours 46 minutes    60

No. 4 hatch
(two hatch section)

 or 3,855 = 64 hours 15 minutes    60