Naval Architecture & Dry-Bulk Stowage
Bulk Carrier Stowage Factor & Full-and-Down Formula
Calculate Vessel Ideal Stowage Factor V_hold / DWT_cargo, Maximum Loadable Tonnage MIN(DWT_cargo, V_hold / (SF * (1 + bs))), Deadweight Utilization, and Cube-Out vs Weigh-Out status.
Determine whether a dry-bulk vessel cubes out in the holds or weighs out at Plimsoll draft!
Every dry-bulk shipmaster and supercargo aims to sail "Full and Down"—100% hold cubic volume filled simultaneously with hull submerged to its maximum Summer Load Line Cargo Deadweight DWT_cargo (Total DWT minus fuel, fresh water, lubes, and constants)! Compare the vessel’s Ideal Design Stowage Factor SF_vessel = V_hold / DWT_cargo (m^3/MT) against Effective Commodity Stowage Factor SF_eff = SF_cargo * (1 + bs_pct) (including Broken Stowage bs_pct for bagged/baled voids): if SF_eff > SF_vessel (light barley, woodchips, sunflower meal), holds hit 100% volume at V_hold / SF_eff < DWT_cargo ("Cube-Out"); if SF_eff < SF_vessel (heavy iron ore, copper concentrate), hull hits summer draft at DWT_cargo with holds partially empty ("Weigh-Out")!
Verify on Supramax Cargo_Deadweight DWT_cargo = 50,000 MT (B2), Hold_Grain_Cubic V_hold = 63,000 m^3 (B3 -> Vessel Design Stowage Factor = 63,000 / 50,000 = 1.2600 m^3/MT in E2), Barley_Stowage_Factor SF_cargo = 1.40 m^3/MT (B4), and Broken_Stowage bs_pct = 0.00 (free-flowing bulk grain, B5): Maximum Loadable Cargo is MIN(50,000, 63,000 / 1.40) = 45,000 MT (E3), Deadweight Utilization is 45,000 / 50,000 = 0.9000 (90.00% in E4, forfeiting 5,000 MT of deadweight!), and Stowage Regime flags "Cube-Out: Hold Volume Full" (E5)! Switch SF_cargo to Iron Ore 0.45 m^3/MT in cell B4: Loadable Cargo caps at 50,000 MT (100% DWT, "Weigh-Out: Summer Draft Reached")!
| Dry-Bulk Stowage Metric (50,000 MT Cargo DWT, 63,000 m^3 Hold, SF=1.40) | Formula | Verified Output |
|---|---|---|
| Vessel Ideal Stowage Factor (m^3/MT) | V_hold / DWT_cargo | 1.2600 m^3/MT |
| Maximum Loadable Cargo (MT) | MIN(DWT_cargo, V_hold / (SF * (1 + bs))) | 45,000.00 MT |
| Deadweight Draft Utilization | Loadable_Cargo / DWT_cargo | 0.9000 (90.00% DWT Used) |
| Naval Stowage Limitation | SF_eff vs SF_vessel | Cube-Out: Hold Volume Full |
Maximum Loadable Cargo Tonnage Formula
Validate DWT_cargo > 0, V_hold > 0, SF_cargo > 0, and bs_pct >= 0!
=LET(dw_c, B2, vl_h, B3, sf_c, B4, bs_p, B5, IF(OR(dw_c <= 0, vl_h <= 0, sf_c <= 0, bs_p < 0), "Invalid Stowage Plan", ROUND(MIN(dw_c, vl_h / (sf_c * (1 + bs_p))), 2)))Cube-Out vs Weigh-Out vs Full-and-Down Classifier Formula
Note how a two-commodity parcel charter mixes dense steel coils in lower holds with light grain/timber above to hit SF_blend = 1.2600 m^3/MT ("Full and Down Optimal")!
=LET(sf_ef, B4 * (1 + B5), sf_vs, B3 / B2, IF(ISTEXT(E3), E3, IF(ABS(sf_ef - sf_vs) < 0.0001, "Full and Down Optimal", IF(sf_ef > sf_vs, "Cube-Out: Hold Volume Full", "Weigh-Out: Summer Draft Reached"))))Try the example
Use the original values or change them to test your understanding.