State of the Art in Protection of Bottom Against Scour Caused by Marine Propulsors

Belyaev, N. D.; Климович, В. И.

doi:10.1007/s10749-019-01054-4

Cited by 5 publications

(5 citation statements)

References 3 publications

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“…Perhaps it should also be mentioned that as was implied early on, the effect of an abstract (having nothing to do with nature) decision-making motive and mindset is liable to continue to have a degrading effect on port areas and beyond, and we will have a relatively easy means of displaying these effects. Of course, some protective measures have been introduced, such as the rip-rap technique, and we will be able to monitor their effectiveness [35,36]. Based on our calculation, we can recommend a rip-rap protection area in the northern part of Basin 1 along the entire container terminal and 40 m in lateral distance (Figure 15).…”

Section: 10 X For Peer Review 14 Of 18mentioning

confidence: 99%

Sediment Resuspension Distribution Modelling Using a Ship Handling Simulation along with the MIKE 3 Application

Srše,

Perkovič,

Grm

2023

JMSE

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The environmental effects of ship propellers were not even close to fully examined before the current massive ships were introduced to sea trade. Larger ships, result in greater length, beam, draft and propulsion power. Of concern here is the under-keel clearance (UKC) and applied power, the most important parameters causing sea bottom sediment resuspension and, consequently, the transport and deposition of washed sediments. The problems are multifarious: shorelines could be contaminated with heavy metals, petroleum hydrocarbons and other organic chemicals, which are sometimes buried deep in the sediment bed. The effects of resuspension on marine life have been well documented by marine biologists. Further, a ship passing through a flow field may have a significant hydrodynamic effect on the shipping channel: waves generated by moving vessels can accelerate shoreline erosion; erosion around quay piles have a negative impact on sea flora. Waves can also affect other manoeuvring vessels or ships at berth. Available empirical models are applicable for a steady state condition, addressing velocity and, consequently, shears at the sea bottom for defined UKC and states of applied power. The idea here is to calculate material resuspension dynamically in the water column based on realistic manoeuvring conditions, which can be a matter of some complexity. During a manoeuvre, the pilot must bring the ship into or out of the harbour in the safest possible way, operating the telegraph, rudder, thrusters and possibly tugs, and also co-ordinating the work of the linesmen. The jet speed powering the vessel is not only a function of the speed of the propeller, but also of the present speed of the ship, which has an effect on the propeller’s constantly changing torque. Additionally, the bathymetry is constantly changing, and the streamlines hit not only the seabed, but also the bank and other structures of the harbour basin. The resuspended material remains in the column long after the ship has finished manoeuvring, moving slowly through the entire water column and being transported not only by the remaining streamlines of the ship but also by general currents. Realistic manoeuvring parameters can be obtained from real-time simulations with a real crew using state-of-the-art Full Mission Bridge Simulators (FMBS); eddies and the like contribute to the distribution and material resuspension and can be calculated by applying numerical modelling. In this paper, a container ship departure manoeuvre is simulated dynamically using Wartsila FMBS obtained data, which are postprocessed and coupled with the MIKE 3 FM hydrodynamic modelling application to which we add the precise port of Koper bathymetry to gain ship propeller spatial jet velocity distribution in specific time domains. Obtained jet velocity distribution is further coupled with the MIKE 3 MT particle tracking application to visualize total resuspended sediment transport patterns, etc. Container ships were selected to amplify the urgency of this phenomenon; they are the most intrusive in terms of resuspending and scouring the seabed given their powerful engines and larger propellers. Passenger ships could have been used, car carriers, or even tankers; but the fear among scientists is that the issue will not be taken seriously enough by certain stakeholders.

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Section: 10 X For Peer Review 14 Of 18mentioning

confidence: 99%

Sediment Resuspension Distribution Modelling Using a Ship Handling Simulation along with the MIKE 3 Application

Srše,

Perkovič,

Grm

2023

JMSE

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“…There are several types of sediment scour prevention techniques: Riprap (basalt, granite, syenite, quartzite, limestone); rip-rap impregnated with asphalt primer; rip-rap impregnated with underwater concrete; wired concrete block mats; concrete slabs; concrete-filled fabric mattresses; stonefilled fibre-reinforced bitumen mattresses; geosynthetic bags, mattresses, tubes and containers filled with sand, gravel [7].…”

Section: Port Bottom Rip-rap Technique To Prevent Sediment Scouringmentioning

confidence: 99%

Minimisation of Propeller-Induced Sediment Resuspension with Rip-Rap System

Srše¹,

Perkovič²,

Grm³

2023

JMS

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Sediment resuspension caused by the movement of propellers during manoeuvring is a major problem in daily port operations. Negative impacts include: Marine flora and fauna, sediment erosion that weakens berth structures, sediment deposits that require dredging. Later, this leads to delays in port operations. Several authors have proposed different methods to cope with this problem. This paper presents methods and tools to determine the critical propeller jet velocities, which are the most important parameter to determine the size of the bank stabilisation system. The tool is a bridge simulator that can be used to simulate the intrusive departure manoeuvre of a ship. The ship motion data are analysed to determine the critical shear stress of the sediment particles. The critical velocity induced by the propeller jet is determined using the German method.

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“…The following is a simplified equation (10) for determining the velocity of the propeller jet at a certain distance (x) and radius (r) from the propeller plane.…”

Section: 𝑉 = 𝐶 𝑓 𝑃 𝜌 𝐷 (4)mentioning

confidence: 99%

“…Another solution is active docking fenders. Various techniques are used in ports around the world to overlap the harbour floor to prevent re-suspension, which have advantages and disadvantages [10].…”

Section: Recommended Solutions To Minimise Sediment Resuspensionmentioning

confidence: 99%

“…The most common types of scour protection are: Riprap (basalt, granite, syenite, quartzite, limestone); riprap impregnated with asphalt primer; riprap impregnated with underwater concrete; cabled concrete block mats; concrete slabs; concrete-filled fabric mattresses; stone-filled fibre-reinforced bitumen mattresses; geosynthetic bags, mattresses, tubes and containers filled with sand, gravel or a combination thereof [10].…”

Section: Techniques To Prevent Scouring Of the Harbour Bottommentioning

confidence: 99%

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Solutions to Minimize Sediment Resuspension in Ports

Srše¹,

Perkovič²,

Androjna³

et al. 2022

JMS

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Sediment resuspension has, among other things, negative consequences for marine flora and fauna. A solution to this problem could lie in alternative ship manoeuvres, automated mooring systems and bottom protection techniques. The paper deals with the methodology for determining sediment resuspen-sion, which consists of real-time kinematic measurements and in-situ meas-urements with (PNS-RTK) sensors. Real-time data from the manoeuvring vessel is used to determine the critical vessel rate per minute (RPM) or pro-peller jet velocity on the seabed and to identify the most common critical ves-sel manoeuvres on approach to port and departure. The Full Mission Bridge Simulator (FMBS) can be an excellent simulation tool for the analysis of real-time and on-site measurements, which is proposed for further research.

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State of the Art in Protection of Bottom Against Scour Caused by Marine Propulsors

Cited by 5 publications

References 3 publications

Sediment Resuspension Distribution Modelling Using a Ship Handling Simulation along with the MIKE 3 Application

Sediment Resuspension Distribution Modelling Using a Ship Handling Simulation along with the MIKE 3 Application

Minimisation of Propeller-Induced Sediment Resuspension with Rip-Rap System

Solutions to Minimize Sediment Resuspension in Ports

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