Structure
Marine Structural Engineering & FEM Analysis
Navtech delivers structural design and analysis for ships, barges and offshore units — from rule-based scantling checks to detailed finite element models supporting deck strengthening, heavy lifts, helidecks and major conversions.
Rule scantling checks and structural design
Every structural scope starts with the rules. We carry out global and local scantling assessments against the applicable class rules, identify where existing structure is deficient, and design reinforcement that a yard can actually build — practical bracket details and stiffener arrangements rather than theoretically optimal solutions that cannot be fitted in place.
- Global and local scantling checks to class rules for hull girder and local structure
- Midship section design and structural drawings for newbuilds
- Reinforcement design for deficient or corroded structure
- Production-ready structural drawings, nesting information and material take-off
Finite element analysis (FEA/FEM)
Where rules do not cover the load case — a crane foundation, a helideck, a heavy module on deck, or an unusual conversion — we build a finite element model and demonstrate compliance directly. Models are built at the level of detail the problem needs, with clearly stated boundary conditions and load cases so that class reviewers can follow the logic without a second submission cycle.
- Global FE models for hull girder response and direct strength assessment
- Local fine-mesh models for foundations, brackets and stress concentrations
- Crane pedestal, A-frame and winch foundation analysis
- Helideck structural analysis to CAP 437 and class requirements
- Grillage and sea-fastening design for project cargo and heavy lifts
Fatigue, buckling and vibration
Strength alone does not keep a structure in service. We assess fatigue life at critical details, run buckling checks on plating and stiffened panels, and investigate vibration where machinery or propeller excitation is causing problems in accommodation or local structure.
- Fatigue assessment using simplified and spectral methods
- Plate and stiffened panel buckling checks
- Vibration investigation and mitigation for hull and superstructure
- Residual strength assessment for corroded or damaged structure
Conversions, retrofits and deck strengthening
A large share of our structural work supports conversion projects — oil-to-bitumen tanker conversions, barge modifications for crane operations, equipment retrofits and deck strengthening for new operating profiles. We coordinate the structural scope with the stability, piping and electrical disciplines so the package arrives at class as one consistent submission.
- Deck strengthening for crane, jacking and heavy equipment loads
- Structural modifications for bitumen and product tanker conversions
- Foundations and seatings for BWTS, scrubbers, boilers and generators
- Structural repair specifications and costed damage assessments
Frequently asked questions
When is finite element analysis actually required?
Whenever the load case falls outside what prescriptive rules cover — crane and A-frame foundations, helidecks, heavy modules on deck, unusual openings, or conversions that change how the hull girder behaves. Class will typically ask for direct calculation in these cases. Where rules do cover the case, a rule check is faster and cheaper, and we will say so.
Which software do you use for structural analysis?
We work with mainstream, properly licensed commercial FE and naval architecture packages together with class society rule-check tools, and we select the toolset to match what the reviewing society expects to see. Model files and calculation records are supplied with the deliverables so the work can be independently verified.
Can you design deck strengthening for a crane installation?
Yes — this is one of our most frequent scopes. We model the crane loads including slewing and dynamic cases, assess the existing deck and supporting structure, design the reinforcement and pedestal, and prepare the class submission. Sea-fastening and mooring analysis for the operation can be covered in the same package.
Do you support the shipyard during fabrication?
Yes. Drawings are prepared with yard buildability in mind, and we stay available through fabrication for technical queries, site clarifications and as-built adjustments. Where a scope demands it we attend the yard.
What do you need to prepare a structural quotation?
Vessel particulars and class society, the structural drawings you hold (midship section, deck plans, shell expansion), a description of the new loads or modification, and your target dates. If drawings are missing we can quote a 3D scan and as-built reconstruction as part of the scope.
Have a vessel and a scope in mind?
Share your drawings, class society and target dates — we respond within 24–48 hours.