Lashing forces and container tracking backbone for cargo ship decomposition

System

Container Ship Cargo Management System, seventh decomposition session. Decomposed the {{entity:Lashing and Securing Calculator}} (safety-critical structural assessment) and the {{entity:Container Tracking and Inventory System}} (core data backbone). 7 of 9 subsystems now have component-level decomposition. 158 total requirements across 7 documents. Two subsystems remain: Cargo Operations Display and Decision Support, and Terminal Interface and EDI Gateway.

Decomposition

The {{entity:Lashing and Securing Calculator}} was decomposed into six components reflecting the CSS Code Annex 13 balance-of-forces methodology: three force domain calculators ({{entity:Stack Weight Calculator}} {{hex:50E73918}}, {{entity:Racking Force Calculator}} {{hex:40E53958}}, {{entity:Wind Force Estimator}} {{hex:40E53158}}) feed into a central {{entity:Lashing Rod Load Analyzer}} {{hex:50F73858}}, which computes per-lashing element loads as percentage of safe working load. The {{entity:CSS Code Compliance Engine}} {{hex:40E77958}} acts as the validation gate, applying both the simplified method and the vessel’s Cargo Securing Manual rules. The {{entity:Securing Equipment Database}} {{hex:40853158}} provides lashing rod SWL values, twist-lock ratings, and bay-specific attachment point geometry.

The {{entity:Container Tracking and Inventory System}} was decomposed into six components built around a dual-authority data pattern: {{entity:Container Registry}} {{hex:40851148}} (master attribute data) and {{entity:Bay Plan Manager}} {{hex:40B53308}} (spatial stowage data) as independent authorities, with a {{entity:Container Status Engine}} {{hex:40B57B08}} implementing lifecycle state management. {{entity:Crane Position Interface}} {{hex:50B57208}} receives OPC-UA position confirmations from crane PLCs, {{entity:Container Event Logger}} {{hex:40A57B58}} maintains the SOLAS-required audit trail, and {{entity:Booking and Manifest Linker}} {{hex:40A53358}} reconciles commercial bookings against loaded containers.

flowchart TB
  SWC["Stack Weight Calculator"]
  RFC["Racking Force Calculator"]
  WFE["Wind Force Estimator"]
  LRLA["Lashing Rod Load Analyzer"]
  SED["Securing Equipment Database"]
  CSCE["CSS Code Compliance Engine"]
  SWC -->|stack loads| LRLA
  RFC -->|racking forces| LRLA
  WFE -->|wind forces| LRLA
  SED -.->|SWL data| LRLA
  SED -.->|bay config| SWC
  LRLA -->|load results| CSCE
  SWC -->|weight verdicts| CSCE
  SED -.->|CSM rules| CSCE

```mermaid
flowchart TB
  CPI["Crane Position Interface"]
  CR["Container Registry"]
  BPM["Bay Plan Manager"]
  CSE["Container Status Engine"]
  CEL["Container Event Logger"]
  BML["Booking and Manifest Linker"]
  CPI -->|position confirms| BPM
  CPI -->|move events| CEL
  CSE -->|state updates| CR
  CSE -->|slot status| BPM
  BML -->|booking links| CR
  CSE -->|state transitions| CEL

Analysis

Cross-domain search on {{entity:CSS Code Compliance Engine}} found 93.75% Jaccard similarity with the {{entity:Segregation Rules Engine}} and {{entity:VGM Reporting and Audit Module}} within the same system — expected, as all three are regulatory compliance validation components with rule-engine architectures. More interestingly, the {{entity:Regulatory Compliance and Discharge Reporting Module}} from the water treatment plant decomposition shares 90.6% similarity, confirming that regulatory compliance engines across maritime and environmental domains share deep structural traits: rule-governed, system-integrated, signal-processing components that validate operational state against an external regulatory corpus.

Lint reported 8 findings (3 high, 4 medium, 1 low). The 3 high findings are ontological mismatches where physical constraints are imposed on entities classified without the Physical Object trait — these affect pre-existing requirements from earlier sessions ({{stk:STK-NEEDS-004}}, {{sub:SUB-REQS-029}}, {{sub:SUB-REQS-035}}). Two medium findings flag degraded-mode requirements ({{sub:SUB-REQS-040}}, SUB-SSMS-009) lacking quantified performance floors. Duplicate architecture decisions ({{sys:ARC-DECISIONS-009}}/011 and {{sys:ARC-DECISIONS-010}}/012) were created due to a parse error during this session and should be cleaned up in QC.

Requirements

Created 14 subsystem requirements ({{sub:SUB-REQS-053}} through {{sub:SUB-REQS-066}}): 8 for lashing (stack weight calculation, recalculation speed, force balance, racking limits at 75% of ISO 1496-1 test load, wind force estimation, CSS Code compliance, securing equipment SWL traceability, and degraded-mode with worst-case CSS Code accelerations) and 6 for container tracking (24,000-TEU registry capacity, 5-second bay plan update, voyage+90-day event retention, lifecycle state machine with 2-second notification latency, OPC-UA crane integration with position validation, and 60-second booking reconciliation).

Created 5 interface requirements ({{ifc:IFC-DEFS-028}} through {{ifc:IFC-DEFS-032}}): lashing-to-stowage synchronous API, stability-to-lashing motion parameter feed at 10-second intervals, BAPLIE/COPARN/CODECO EDI exchange with 30-second acknowledgement, container tracking-to-stowage 500ms per-bay query response, and VGM-to-registry 5-second sync with 5% discrepancy threshold.

All 5 interface requirements have corresponding verification entries ({{sys:VER-METHODS-036}} through {{sys:VER-METHODS-040}}) with trace links. All subsystem requirements traced to parent system requirements ({{sys:SYS-REQS-007}} for lashing, {{sys:SYS-REQS-008}} for container tracking).

Next

Two subsystems remain for component decomposition: Cargo Operations Display and Decision Support (operator HMI, relatively straightforward) and Terminal Interface and EDI Gateway (external comms adapter). Once both are decomposed, the system can be marked first-pass-complete and proceed to QC. The duplicate ARC-DECISIONS entries and the 3 high-severity lint findings (physical trait mismatches) should be addressed in the QC session. The two degraded-mode requirements without performance floors also need remediation.

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