KDS Offshore
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Capability · 03 / 09 · Hydrodynamics

Hydrodynamic Optimisation

CFD-driven hull and propulsor refinement.

Lead time · 6–10 weeksFixed-fee, fixed-scopePrincipal-ledAuthor · Sérgio Ribeiro e Silva, PhDLast reviewed ·
✦ TL;DR

Hydrodynamic optimisation is the CFD-driven refinement of a hull, appendages, and propulsor to reduce resistance, fuel burn, and emissions across the real operating profile — not a single design speed. KDS Offshore uses STAR-CCM+, OpenFOAM, and WAMIT, validated against towing-tank or sea-trial data, and reports residuals in every job.

Overview

What this service is

Hydrodynamic performance is what most operators feel as a fuel bill. We use potential-flow theory for fast scans and full Reynolds-Averaged CFD for the cases that matter, validated against model-test campaigns when one exists.

Wave, current, and wind loads on offshore structures are evaluated with the Morison approach and three-dimensional panel methods. The output is a numerical wind-and-current load coefficient set the designer can defend.

Typical outcomes: 10–20% reduction in fuel burn at cruise, measurable improvement in roll stability margin, and a CFD report (~80 pages) the class society and the operator can both read.

See our methods →

Outcomes

Numbers we expect to defend

−18%
fuel burn at cruise
SeaPower 12 m pilot boat, 2022 (CFD-validated)
8–9%
voyage fuel saved on a synthetic Atlantic case
SOOS programme, published at IMDC 2024 and ICCAS 2024
3–5%
typical residual vs sea-trial data
validated mesh on resistance prediction
~80 pp
CFD report per study
class-society-ready, with documented solver setup
Deliverables

What you get

01
CFD report (~80 pp)
02
Hull-form optimisations
03
Resistance curves & propulsion system design
04
Wake fraction & free-surface calculation
05
Wind & current load coefficients
06
Documented solver setup (reproducible)
07
Bilge-keel design via CFD
Fit

When this is the right call

✓ When to use
  • A parametric study with 10+ hull variants to screen quickly (CFD beats tank time by orders of magnitude).
  • A retrofit fuel-saving brief — the operator wants to know what 1° of trim or 0.5 kn of speed actually costs.
  • A propulsor design where wake interaction matters and tank data is incomplete.
  • Wind, wave and current load coefficients of any type of seagoing vessel to be used on a weather routing software tool can be submitted by KDS Offshore to a class-society for external review and due accreditation process.
✗ When not to use
  • A single validated hull with extensive tank data already in hand — re-running CFD adds little.
  • Cavitation prediction at full propulsor speed without a dedicated cavitation tunnel campaign.
Methodology

How we run a project

  1. 01 / 04

    Baseline assessment

    Existing geometry, performance data, and the operating profile. The operating profile is the most important input — most fuel is burned at one or two speeds, not across the whole envelope.

  2. 02 / 04

    Simulation campaign

    STAR-CCM+ or OpenFOAM at the relevant Froude numbers. Validation against towing-tank or sea-trial data wherever it exists.

  3. 03 / 04

    Design modifications

    Hull, appendage, and propulsor refinements proposed and quantified. Each change comes with a fuel-saving estimate and a confidence interval.

  4. 04 / 04

    Validation & handover

    Final solver setup, mesh, and post-processing scripts handed over. The model is yours after the project.

Tools & methods

Software stack we use

  • STAR-CCM+
  • OpenFOAM
  • WAMIT (potential flow / panel method)
  • MITCHELL1 · wavemaking resistance (thin-ship theory)
  • DAWSON0 · wavemaking resistance (linear free-surface)
  • Ansys Aqwa
  • AUTOHYDRO
  • Maxsurf
  • Ship@Sea (KDS proprietary, FORTRAN)
Regulatory context

Frameworks we help you satisfy

  • EEDI / EEXI (IMO MEPC.328(76))CFD-derived hydrodynamic data feeds the design and existing-ship efficiency indices.
  • CII (IMO Carbon Intensity Indicator)Operational fuel burn modelled by CFD informs CII forecasting and rating uplift.
  • FuelEU MaritimeCFD-validated trim and speed advice reduces well-to-wake GHG intensity for compliance.
  • ITTC quality manualV&V protocols followed on every CFD report; residuals published, not hidden.
Vessel types

Where this discipline applies

  • Pilot boats and harbour craft
  • Working boats, supply vessels, offshore service vessels
  • Container ships, bulkers, tankers (operational trim/speed work)
  • Cruise and passenger vessels
  • Offshore structures (wind/current loading)
  • Naval and patrol craft
Selected work

Where this discipline was used

·01SeaPower 12 m pilot boat — −18% fuel burn at cruiseSeaPower2022↗·02OneOcean working boat preliminary CFDOneOcean2021↗
Common questions

FAQ

When is CFD better than a towing-tank test?

When the parametric space is large (you are exploring 20 hull variants, not validating one), when the Reynolds number cannot be reproduced at model scale, or when the budget for tank time is gone. CFD is not always cheaper, but it is always faster to iterate on.

How accurate is your CFD compared to sea trials?

For resistance, typically within 3–5% on a validated mesh. For propulsion, 5–8% depending on propeller modelling. We publish the residuals in every report.

Do you cover seakeeping as well as resistance?

Yes — Ansys Aqwa for linear seakeeping, Ship@Sea (our in-house code) for non-linear time-domain simulation when the response is large.

Research

Reference publications

  1. [1]Ribeiro e Silva, S., Varela, J. M. (2022). Ship Gyroscopic Roll Stabilisation. 41st International Conference on Ocean, Offshore and Arctic Engineering (OMAE 2022), ASME, Hamburg. Paper OMAE2022-7953.
  2. [2]Ribeiro e Silva, S., Bento Moreira, M. (2024). An optimisation-based approach to reduce fuel consumption and emissions from shipping navigation. IMDC 2024, Amsterdam. ↗
  3. [3]Ribeiro e Silva, S., Bento Moreira, M. (2024). An integrated real-time Ship Operation Optimisation System (SOOS). ICCAS 2024, RINA, Genoa.
Other capabilities

Eight other disciplines, one office

✦ Brief this service · CFD & hydrodynamics

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A 30-minute call with a principal. No deck, no sales engineer. Two engineers, your problem, an honest answer about whether KDS is the right firm.

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