Ship Underwater Radiated Noise Retrofit & Energy Trade-Off Tool
Screen underwater radiated noise retrofit options against vessel
speed, fuel consumption, voyage time, operating cost and carbon
impact. Compare the modeled noise benefit of propeller, wake-flow,
machinery-isolation and maintenance measures while seeing whether
energy savings or penalties change the economic case.
Currency selector changes display only. No exchange-rate conversion is performed.
Energy Trade-Off
Speed-sensitive fuel demand, retrofit energy penalties and annual fuel change
Retrofit Economics
CAPEX, maintenance, schedule impact, annual benefit and cost per modeled dB
Baseline Noise & Operating Condition
Use a vessel-specific underwater radiated noise metric measured or
estimated under a consistent operating condition. This tool treats
the entered dB values as a comparative screening metric rather than
a certified prediction.
dB
dB
knots
knots
dB / 10% speed
User-entered screening assumption. Positive values mean slower speed is modeled as quieter.
Aggregate Retrofit Effect
dB
%
Reduces nominal reductions for interaction, uncertainty and overlap between measures.
%
Positive increases energy use. Negative reduces energy use.
$
$
Fuel & Energy Model
MT/day
%
The remaining share is treated as relatively insensitive to vessel speed.
Speed-sensitive fuel scales with the entered speed ratio raised to this exponent.
$
/MT
days/year
tCO₂ / MT fuel
Voyage-Time Trade-Off
nautical miles
voyages/year
$
/hour
Baseline Vessel Condition
dB
dB
knots
knots
dB / 10% speed
%
Retrofit Measures
The example values are illustrative only. Replace them with
supplier, model-test, sea-trial or engineering estimates for the vessel.
Individual realization factors are applied first, then the combined
realization factor accounts for interaction between selected measures.
Use
Retrofit Measure
Noise Reduction dB
Realization %
Fuel Impact %
CAPEX
Annual Maint.
Fuel, Carbon & Voyage Assumptions
MT/day
%
$
/MT
days/year
tCO₂ / MT fuel
nautical miles
voyages/year
$
/hour
Noise, Energy & Retrofit Results
Aggregate retrofit screening
Enter vessel data
Enter baseline noise, vessel speed, fuel consumption and retrofit
assumptions to compare modeled underwater noise reduction with the
resulting energy and economic trade-offs.
Modeled Post-Retrofit Noise Metric
N/A
Comparative screening estimate using entered speed and retrofit assumptions
Total Modeled Noise Reduction
N/A
Speed contribution plus effective retrofit contribution
Noise Target Margin
N/A
Relative Acoustic Energy Remaining
N/A
Speed Noise Contribution
N/A
Retrofit Noise Contribution
N/A
Baseline Fuel
N/A
Post-Retrofit Fuel
N/A
Annual Fuel Change
N/A
Annual Fuel Cost Change
N/A
Voyage Time Change
N/A
Annual Schedule Cost
N/A
Annual CO₂ Change
N/A
Selected Retrofit CAPEX
N/A
Annual Maintenance
N/A
Net Annual Economic Benefit
N/A
Simple Payback
N/A
CAPEX per Modeled dB
N/A
Selected Retrofit Measures
Advanced mode
Measure
Nominal dB
Individual Realization
Effective Before Interaction
Fuel Impact
CAPEX
Annual Maint.
Underwater Noise Screening
Fuel & Energy Trade-Off
Voyage & Economic Trade-Off
Annual Economic Components
Post-Retrofit Noise Sensitivity
Operating speed vs retrofit realization
Operating Speed \ Realization
-15%
Base
+15%
Model approach:
speed-related noise change equals the entered percentage speed
change divided by 10 × the user-entered dB sensitivity. Retrofit
noise reductions are reduced by individual realization assumptions
and then by the combined realization factor. The resulting dB
change is used only as a comparative screening metric. Relative
acoustic energy is shown using 10 raised to the power of negative
dB reduction divided by 10. Speed-sensitive fuel scales with the
new-to-baseline speed ratio raised to the entered exponent, while
the remaining fuel share is held constant. Selected retrofit energy
impacts are then applied multiplicatively.
Screening tool only.
Underwater radiated noise is highly dependent on frequency, vessel
operating condition, propeller cavitation, machinery excitation,
hull structure, wake field, loading, draft, sea state, water depth,
measurement geometry and the metric or standard being used. Noise
reductions from multiple measures may interact and should not be
assumed to add directly without supporting engineering analysis.
The speed-noise relationship in this tool is entirely user-defined.
The fuel model is a simplified planning approximation and does not
replace vessel performance curves, propulsion modeling or sea-trial
data. Relative acoustic energy is a mathematical comparison of the
entered dB change and is not a prediction of biological impact,
detectability, regulatory compliance or environmental acceptability.
Use qualified naval architects, acoustic specialists, class guidance,
approved measurement methods and vessel-specific engineering before
retrofit procurement or operational changes.
