Ship Structural Design
Ship Structural Design
Navtech provides ship structural design for newbuilds, conversions and repairs — hull scantlings to class rules, midship sections, deck and foundation reinforcement, and production drawings a yard can build, supported by direct calculation where the rules do not reach.
Hull scantling design to class rules
Structural design begins with the rule check — plating thickness, stiffener sizing, primary member scantlings and hull girder capacity assessed against the applicable class rules. We produce the midship section and structural arrangement from that basis, and where existing structure falls short we identify it precisely rather than reinforcing broadly and expensively.
- Midship section design and hull girder section modulus verification
- Plating, stiffener and primary member scantling calculations
- Shell expansion, deck, bulkhead and tank boundary structural drawings
- Corrosion allowance assessment and renewal specification
- Structural drawings for newbuild construction
Reinforcement and strengthening design
Most of our structural work involves existing vessels taking on loads their original designers never contemplated. The engineering challenge is designing reinforcement that carries the load and can physically be installed in a confined, in-service space — which usually rules out the theoretically ideal solution.
- Deck strengthening for cranes, jacking systems and heavy equipment
- Foundations and seatings for boilers, BWTS, scrubbers and generators
- Local reinforcement around new openings and penetrations
- Structural modification for conversions and change of service
- Buildable bracket, insert plate and stiffener details for yard installation
Direct strength assessment and FEM
Where prescriptive rules do not cover the load case, class requires direct calculation. We build finite element models at the level of detail the problem justifies, with clearly documented load cases and boundary conditions so a reviewer can follow the argument without asking for a second submission.
- Global and local finite element models for direct strength assessment
- Crane pedestal, A-frame and heavy foundation stress analysis
- Fatigue assessment at critical structural details
- Plate and stiffened panel buckling verification
- Residual strength assessment of corroded or damaged structure
Damage assessment and structural repair
Following grounding, contact damage or advanced corrosion, owners need a defensible view of what must be repaired now and what can be monitored. We survey, assess the remaining strength, and specify repairs with the calculations to support them to class and to underwriters.
- Damage survey and residual strength evaluation
- Repair specification with staged and permanent options
- Costed repair assessments for owners and insurers
- Steel renewal drawings and material take-off
Frequently asked questions
Do you design structure for newbuilds as well as modifications?
Yes. For newbuilds we develop the midship section and full structural arrangement from the rule basis through to production drawings. For existing vessels we design reinforcement and modification, which is the larger part of our structural workload.
How do you decide between a rule check and finite element analysis?
If the class rules cover the load case, a rule check is faster, cheaper and sufficient — and we will tell you so. FEM becomes necessary for concentrated loads and geometries the rules do not address: crane foundations, helidecks, heavy modules, large openings and unusual conversions. Class will normally require direct calculation in those cases.
Can you design strengthening that the yard can actually install?
That is the constraint we design to. Reinforcement in an existing vessel has to be installed in confined spaces, often with the vessel partly in service, so we detail brackets, insert plates and stiffeners for the access and equipment available. Elegant designs that cannot be welded in place are of no use to anyone.
What if the vessel’s structural drawings no longer exist?
We rebuild them. A 3D laser scan combined with thickness measurements and physical survey gives us an accurate as-built model to design against, and you keep that model as a reliable drawing baseline for future work.
What information do you need to quote structural design work?
Vessel particulars and class society, the structural drawings you hold — midship section, deck plans, shell expansion — a description of the new loads or modification, recent thickness measurement reports if relevant, and your target submission date.
Related engineering services
Have a vessel and a scope in mind?
Share your drawings, class society and target dates — we respond within 24–48 hours.