The build‑up is the complete arrangement of keel blocks, bilge blocks, shores, wedges, and supplemental supports configured specifically for a vessel’s hull form. It establishes the safe landing geometry required for docking, ensuring the ship settles evenly, maintains structural alignment, and meets MIL‑STD‑1625D(SH) tolerances throughout the docking evolution.
The build‑up establishes the precise block and support geometry required for a vessel to land safely inside the dry‑dock. Every element — keel blocks, bilge blocks, shores, wedges, and supplemental supports — is positioned to match the ship’s hull form and weight distribution. A correct build‑up ensures the vessel settles evenly, maintains structural alignment, and prevents point‑loading or unintended stress concentrations during the docking evolution.
The keel block line forms the primary landing surface for the vessel and must be aligned to the ship’s centerline with zero deviation. Block heights are set according to the vessel’s docking plan, ensuring the keel lands uniformly along its length. Each block is checked for level, plumb, and correct spacing, with tolerances maintained in accordance with MIL‑STD‑1625D(SH). The keel line is the backbone of the build‑up, and its accuracy determines the success of the entire docking.
Bilge blocks provide lateral stability and prevent the vessel from rolling once it is fully landed. Their placement is determined by the hull’s bilge radius, frame spacing, and docking plan geometry. Each bilge block must be positioned so it contacts the hull only after the keel has fully settled, ensuring no premature side loading. Proper bilge block alignment maintains hull symmetry, supports the vessel’s weight distribution, and stabilizes the ship throughout the dry‑dock period.
Top mauls and wedges are used to achieve final alignment and secure the blocks once the ship begins to take weight. Wedges allow fine adjustments to block height and angle, ensuring full and even contact with the hull. During the landing, the dock master directs wedge tightening in a controlled sequence to avoid inducing stress or twisting forces. Proper wedge use ensures the build‑up remains stable and locked in place for the duration of the docking.
The build‑up paper is the formal documentation detailing the exact block configuration for the vessel. It includes keel block elevations, bilge block positions, frame references, hull contact points, and any special support requirements. This document is reviewed and approved before docking and serves as the authoritative reference for the entire build‑up. Accurate build‑up paper ensures compliance with standards, supports safe docking operations, and provides traceability for future dockings of the same vessel.
Before the vessel enters the dry‑dock, the dock master conducts a full verification of the build‑up. This includes checking block alignment, confirming elevations, validating spacing, and ensuring all wedges, shores, and supplemental supports are correctly placed. Any deviation is corrected immediately. Final verification guarantees that the build‑up matches the approved docking plan and that the dry‑dock is fully prepared to receive the vessel safely.