Scantling Calculations in Naval Architecture — Manual vs. AI-Automated Approaches

A scantling calculation determines whether a structural member — a plate, a stiffener, a frame, a girder — meets the minimum size (scantling) required by the applicable classification society rules. It is the most fundamental verification step in ship structural design: if a member fails its scantling check, the design must be revised before construction can proceed.

For naval architects, plan approval engineers, and classification society reviewers, scantling calculations are daily work. The question is how efficiently and accurately they can be performed.

What a scantling calculation involves

• Extracting dimensions — reading the plate thickness, stiffener spacing, stiffener profile, span, and other geometric properties from the structural drawing.
• Identifying the rule requirement — looking up the applicable clause in the classification society rules (IACS CSR, DNV, ABS, etc.) based on the member's location and function.
• Running the formula — calculating the required minimum scantling using the rule formula, which may involve section modulus, moment of inertia, plate thickness, or buckling strength.
• Comparing — comparing the as-designed value against the rule minimum and expressing the result as a margin (percentage above or below the requirement).
• Documenting — recording the calculation with the rule clause reference, input values, and result for the approval record.

Why manual methods are reaching their limits

A midship section drawing alone can contain 200+ structural members. Checking each one manually — extract, look up, calculate, document — takes an experienced engineer several days. Multiply that by the number of drawings in a full structural design package (midship, engine room, cargo hold, fore end, aft end, transverse bulkheads), and the total effort runs into weeks.

Beyond speed, manual calculation is error-prone. A misread dimension, a wrong clause reference, or a formula entry error can result in an under-scantled member passing review — a structural risk that may not be discovered until construction or, worse, in service.

How ShipWright AI works

ShipWright AI reads the structural drawing directly, identifies every member, and runs the complete scantling calculation against the selected classification society rules. It supports IACS CSR, DNV, ABS, Lloyd's Register, Bureau Veritas, and NK. The output is a structured PDF report with PASS/FAIL results, margins, and clause references for every member — produced in minutes, not days.

The tool does not replace the naval architect's judgement — it automates the repetitive calculation and documentation work, freeing the engineer to focus on design decisions and structural optimisation.

Try it free at shipwrightai.org.