dynamic under keel clearance dukc® - lone star · pdf filewave response/setdown heel squat...
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Dynamic Under Keel Clearance
DUKC®Underkeel Clearance Risk Mitigation
and
Channel OptimisationCaptain Jonathon PearceBusiness Development Manager
Houston2 December 2014
Who is OMC International?
• Inventor and sole supplier of DUKC®
• Dr Terry O’Brien involved in 2 PIANC committees
WG 54 (Chairman): Use of Hydro/Meteo Information to
Optimise Port Access
WG 49:Harbour Approach Channel Design Guidelines
• Technical advisors to UKHO TSMAD committees
Data Quality
Tides and Water Levels
• Industrial member of IALA, and VTS committees
Development of UKC Standards for VTS Systems
DUKC® Overview
• Installed at 24 Australian and overseas ports with Port of Montreal system commissioned March 2014
• Safety Record: 110,000+ bulk, container and tanker movements since 1993 without incident (about 1 movement per hour)
• All DUKC® systems covered by PI and PL insurance from TT Club since 2001
• DUKC® is supported 24/7 by an experienced team
PIANC WG49 Channel Depth factors
2.1
UKC Factors
SOMS UKC Concept Study
Wave Response/Setdown
Heel
Squat
Tidal Residual
Static Rule – TOP DOWN approach
Variable Nett UKC Clearance
VARIABLE RISK
Nett Clearance changes for every transit
Is it Safe, Marginal or Unsafe? Static Allowance
Fixed UKC Allowances
Wave Response/Setdown
Heel
Squat
Tidal Residual
NETT – BOTTOM UP approach
Required Water Depth
Fixed NETT Allowance: Minimum Predetermined Clearance
CONSTANT RISK Minimum NETT
Clearance maintained for every transit
Always Safe!
NETT UKC (using real time data)
is referred to as a DYNAMIC APPROACH
SOMS UKC Concept Study
Variable UKC Allowances
Overview: Dynamic UKC (DUKC®)
• Provides a consistent scientific approach to UKC management
• Utilises near real time and forecast environmental data (tides, waves, currents) and uses sophisticated ship modelling to calculate ship motions and UKC
• Rigorous application of PIANC guidelines and limits
• Effective mitigation of grounding hazards
• Implements a shared picture between ship and shore
• Extensive full-scale DGPS validation (>300 vessels)
Squat
• Affected by:– vessel speed through water (inc.
effect of currents)
– acceleration profile
– water depth
– undulations in the depth profile
– vessel block coefficient
– channel blockage factor
– bed roughness and material
– salinity
Squat
• Calculated Squat affected by Equation used
• Effectiveness in relation to the • Vessel,
• Speed profile,
• Surroundings, and
• Environment
Source: PIANC Report 121-2014, Fig D-13
Squat – Channel Blockage
Squat is Unique
Channel Blockage is
like a fingerprint –
\its different for
every port
Squat: Port and Vessel Specific
- Maximum Modelled Speed
- Measured Speed
- Measured Squat
- Maximum Modelled Squat
Inertial Heel
• Sustained inclination of a vessel about its longitudinal axis
• Two primary causes:– Drag due to wind – wind heel– Turning dynamics – inertial heel
and rudder effect
• Occurs when a vessel changes course
• Affected by:– Speed, Radius of Curvature of
Turn– Stability Characteristics (Gm
VCG), Beam
Wave Response
• Only some components of vessel motion lead to vertical hull motion:– Heave, Roll, Pitch
• However, all components (inc. surge, sway & yaw) are modelled to capture coupling effects
• Affected by:– Hull Geometry, Stability Characteristics,
– Vessel Speed (relative to waves)
– Wave Height & Period, Wave to Hull Angle of Incidence
– Wave-Current-Vessel Interaction
• Inherent difficulty and dangerous to generalise wave response of one vessel against another
Validation of Components
SOMS UKC Concept Study
- Maximum Modelled
Speed
- Measured Speed
- Measured Squat
- Maximum Modelled
Squat
No.2 No.1 No.3 No.5 No.7 No.9 Berth
0.0
0.5
1.0
1.5
2.0
2.5
3.0
0 5 10 15 20 25
Distance [km]
Wa
ve
Re
sp
on
se
[m
]
Maximum Wave Response Significant Wave Response Measured Wave Response
DUKC® - System Inputs/Outputs
Win/Win - Productivity & Safety
• OMC’s evidence from existing studies show:
• 95% existing static rule conservative
• Potential for draught increases and/or productivity gains through increased tidal windows
• 4% existing static rule marginal
• Potential for a touch bottom incident. High risk but actual risk never quantified
• 1% existing static rule unsafe
• Very high potential for a touch bottom incident
Under most conditions a static rule will be conservative
However, groundings can occur when a ship is sensitive to the prevailing conditions (this is actual data!)
Case Study - Failure of Static Rule
A static rule won’t tell you when this is the case!
Conservative (95%)
Marginal(4%)
Unsafe(1%)
Marsden Point NZ, Groundings: Eastern Honor & Capella Voyager 2003
Case Study - Port Taranaki
Blue Area
Static Tidal
Window
Orange Area
DUKC Tidal
Window
Static Rules not Sufficient in High Swell Conditions
Primary Outcomes
• Exploits inefficiencies of the Static Rule
– Maximises Safety and
– Maximises productivity and efficiency and
– Increased economic benefits
• Enhanced decision making with transit plan accuracy
• Detailed reports Improved Master/Pilot Information Exchange
• Enhanced vessel scheduling/reduced channel conflicts
• Enhanced contingency planning
• Removes commercial pressures
DUKC® Economic Benefits
“The DUKC program continues to be a major asset forBHP and the Port. As the port grows so does the value ofthe DUKC program, the value is in the order of 7% ofthroughput (circ. 15 million tonnes).The benefits are many:
1) Direct tonnage gain from the additional 50cm inavailable draft over a static system, which adds anextra 7,000 tonnes to a vessels loading
2) The increased sailing window available enables usto sail multiple vessels on a tide.
3) Increased safety because all calculations aremeasurable and are accurate.”
BHP (Port Hedland)
DUKC® System
DUKC® Series 5 Package
• Web based
– Improved access to, and distribution of, information
• Long range planning integrating met-ocean forecasting
• Real time monitoring (onshore & aboard)
– Contingency planning (late departure, vessel overloaded, changing conditions, vessel responsiveness)
– Emergency response (engine failure, rudder failure)
• Upstream integration
– Dynamic Port Capacity Model - analysing port capacity considering many variables dynamically
DUKC® Components
PLAN
Planning
Optimiser
SAIL
Passage Planning
Passage Monitoring
SHORE
Passage Monitoring
SHIP
DATA
Vessel
Met-Ocean
Reporting
ADMIN
System Notification
System Health
User Management
What is DUKC®? An example
Planning and Monitoring
Outputs and Reports
Dredging ConsiderationsUsing DUKC® Methodology
Existing Dredging Planning
• Based on static UKC rules
• “Rule-of-thumb” requirements can translate into millions of tonnes of material being dredged that isn’t required
• A more scientific approach can reduce dredging significantly whilst also improving port access
Current Depths
Proposed Depths
Proposed Depths
REQUIRED DREDGE VOLUME
Current Depths
Planning Dredging Using DUKC®
• DUKC® can help minimise the amount of dredging required
• Exact port accessibility can be determined
• Effects of siltation on operations can be explicitly calculated
• Dredging management plans can be devised to minimise maintenance dredging
DUKC Model Development
• Years of measured and predicted environmental data are collected – (waves, tides, currents, long waves,
wind, atmospheric pressure)
• Custom hydrodynamic models developed for the port
• Custom DUKC solution is developed using the port specific modelling
• Full scale vessel measurements can be used to validate the modelling
measured tide conditions
measured wave conditions
The Analysis Process
• A database of vessels is developed based on previous, and planned vessel visits to the port
• Port operations are simulated with thousands of DUKC calculations using real vessels and real measured climate conditions
• Each DUKC simulation provides an optimised bed depth for that vessel in those conditions
range of container ships
range of tankers / bulk carriers
Optimised bed depth based on DUKC simulation
Thousands of simulations provide thousands of optimised bed depths
Interpretation of Results
• From the thousands of DUKC simulations, OMC collates the optimised bed depth profiles
• Different design depths can be chosen based on operating condition requirements. For example:– Access for 14.5 metre draft tankers on 95% of high
waters,– Access for all inbound vessels on 90% of occasions
regardless of tide,– Minimum requirement of 4 hour operating windows
for container vessels in winter,– Etc.
Different requirements result in different optimised depths.
1. Access for 14.5 metre draft tankers on 95% of high waters.
2. Access for all inbound vessels on 90% of occasions regardless of
tide.
3. Minimum requirement of 4 hour operating windows for container
vessels in winter.
VOLUME OF DREDGING SAVED
Reporting of Results
• Dredge plan profiles
• Charts and maps displaying dredge areas
• Corresponding tables of chainages and depths
Profile Diagrams
Required Minimum Depths by % Access Arrangement for 14.00m T General Containers
Western Option
13
14
15
16
17
18
19
20000 20010 20020 20030 20040 20050 20060 20070 20080 20090 20100 20110 20120 20130 20140 20150
Location Id
Requir
ed D
epth
(m
)
90% 92.5% 95% 97.5% 99%
Very non-uniform optimal profile.Localised depth requirements change steeply due to inertial heel and change of wave incident angle as vessel negotiates turns.
Channel Design Options
Cost-benefit: Dredging for 13.50m T General Container Ships
500,000
550,000
600,000
650,000
700,000
750,000
800,000
850,000
900,000
94.5 95 95.5 96 96.5 97 97.5 98 98.5 99 99.5
Access Arrangement (%)
Vo
lum
e R
eq
uir
ed
(c
ub
ic m
)
Eastern Option Dredging Required (cubic m)
Western Option Dredging Required (cubic m)
Detailed Maps
Average Draft Increases
Channel Depth Option
Dredge Volume
[m3]
Average Draft [m]
Average Benefit to Draft [m]
Existing Depths 0 18.59 0
1 8,000 18.64 0.05
2 25,000 18.67 0.08
3 39,000 18.70 0.11
4 58,000 18.79 0.19
5 163,000 18.88 0.29
6 442,000 18.99 0.40
7 650,000 19.10 0.51
Channel Design/Dredge Optimisation
Minimisation of over-dredgingMaintenance dredging planning
Benefits
• Reduced dredging
– Save money
– Save time
– Minimise environmental impact
– Know exactly what you are getting for your dredging
• Previous studies have saved ports up to 50% on their dredging required
DUKC® for Channel Design
• Considerable benefit for ports operating with DUKC® to optimise their channel profile for best yield
• Derived access percentages reflect future operating outcomes
• Can be used to identify UKC “hot-spots” to prioritise maintenance dredging
Chart Overlays
Chart Overlay Generation
Due to dynamic components:• Overlays are
unique to a vessel• Multiple vessels =
multiple overlays
14.7m Vessel – 12k Area 1
14.7m Vessel – 14k Area 1
14.7m Vessel – 16k Area 1
No Overlay
Squat – Dead Slow Ahead
Squat – Slow Ahead
Squat – Half Ahead
Squat – Full Ahead
Squat – Full Sea Speed
Thank You
SOMS UKC Concept Study