12
T. Soomere
remote danger to some other domain. This viewpoint reflects the above-discussed
paradigm that marine anthropogenic activities with high risks usually have a substantial remote influence. The situation is again essentially asymmetric: the risks
caused by metocean factors or by the coasts or obstacles affect the ship only at a
fixed point but the outcome of an accident may have much wider impact. Therefore,
a consistent implementation of methods and technology for an optimum choice of
the fairway in terms of environmental risks stemming from a ship has to cope with
this paradigm.
The first investigations systematically accounting for this aspect were probably
carried out for the analysis and mitigation of hazards associated with wake waves of
high-speed vessels. It is well known that large vessels sailing at near-critical speeds
in relatively shallow water may produce high wave groups that remain compact for
a long time and may severely impact coastal regions located many kilometres from
the ship lane (Parnell and Kofoed-Hansen 2001; Soomere 2005; Parnell et al. 2007).
The U.S. Patents Nos. 6171021 and 7082355 provide technically and economically
feasible solutions for avoiding the remote influence of dangerous waves. 6
As mentioned above, a complicated set of restrictions and regulations exist for
the rail and road transport of hazardous goods. There have been very few attempts
so far to address these questions in marine conditions. Even in the most comprehensive overviews (Christiansen et al. 2004) this problem is simply mentioned but
no perspectives for this field are outlined. It is addressed at a strategic level in the
framework of transportation of oil products in the Gulf of Mexico (Iakovou et al.
1999). The solution is sought as a selection of paths that minimize a weighted sum
of transport costs and expected risk costs (Fagerholt et al. 2000). The basic risk here
is again a coastal crash, the coastline represents the obstacles and the potential benefit is formulated in terms of economic categories and operational planning of ship
schedules.
An early attempt to address the more general problem of the assessment of risk
levels along fairways has been made in Judson (1997). The objective was to provide
timely risk assessment information to a mariner or decision-maker in a system capable of integration of, among other factors, also historical and metocean information
such as accident location, frequency and type, ice, wind, visibility, environmental
sensitivity and other factors. The resulting collision risk was assessed for each track
in a route plan by applying a predictive accident model patterned after the navigation and collision avoidance process. In essence, this method again addresses the
probability of the accident in the equation of risk.
6 The solutions are targeted at smart fairway design in the context of contemporary fast ferry traffic,
where as a by-product long and high waves are created by ships moving with a specific (critical)
speed, creating a large problem in shallow areas (see Soomere 2009 and references therein). U.S.
Pat. No. 6171021 proposed to design an underwater ramp (equivalently, the fairway crossing such
ramp) so that the water depth abruptly changes. By doing so the ship avoids as much as possible
sailing with critical speed and generating dangerous waves. U.S. Pat. No. 7082355 consists of
a combination of devices that warn the captain when the ship is entering the critical regime in
relatively shallow water. A practical use of this device consists in adjusting the sailing line so that
the danger to the environment caused by vessel waves is minimized.
T. Soomere
remote danger to some other domain. This viewpoint reflects the above-discussed
paradigm that marine anthropogenic activities with high risks usually have a substantial remote influence. The situation is again essentially asymmetric: the risks
caused by metocean factors or by the coasts or obstacles affect the ship only at a
fixed point but the outcome of an accident may have much wider impact. Therefore,
a consistent implementation of methods and technology for an optimum choice of
the fairway in terms of environmental risks stemming from a ship has to cope with
this paradigm.
The first investigations systematically accounting for this aspect were probably
carried out for the analysis and mitigation of hazards associated with wake waves of
high-speed vessels. It is well known that large vessels sailing at near-critical speeds
in relatively shallow water may produce high wave groups that remain compact for
a long time and may severely impact coastal regions located many kilometres from
the ship lane (Parnell and Kofoed-Hansen 2001; Soomere 2005; Parnell et al. 2007).
The U.S. Patents Nos. 6171021 and 7082355 provide technically and economically
feasible solutions for avoiding the remote influence of dangerous waves. 6
As mentioned above, a complicated set of restrictions and regulations exist for
the rail and road transport of hazardous goods. There have been very few attempts
so far to address these questions in marine conditions. Even in the most comprehensive overviews (Christiansen et al. 2004) this problem is simply mentioned but
no perspectives for this field are outlined. It is addressed at a strategic level in the
framework of transportation of oil products in the Gulf of Mexico (Iakovou et al.
1999). The solution is sought as a selection of paths that minimize a weighted sum
of transport costs and expected risk costs (Fagerholt et al. 2000). The basic risk here
is again a coastal crash, the coastline represents the obstacles and the potential benefit is formulated in terms of economic categories and operational planning of ship
schedules.
An early attempt to address the more general problem of the assessment of risk
levels along fairways has been made in Judson (1997). The objective was to provide
timely risk assessment information to a mariner or decision-maker in a system capable of integration of, among other factors, also historical and metocean information
such as accident location, frequency and type, ice, wind, visibility, environmental
sensitivity and other factors. The resulting collision risk was assessed for each track
in a route plan by applying a predictive accident model patterned after the navigation and collision avoidance process. In essence, this method again addresses the
probability of the accident in the equation of risk.
6 The solutions are targeted at smart fairway design in the context of contemporary fast ferry traffic,
where as a by-product long and high waves are created by ships moving with a specific (critical)
speed, creating a large problem in shallow areas (see Soomere 2009 and references therein). U.S.
Pat. No. 6171021 proposed to design an underwater ramp (equivalently, the fairway crossing such
ramp) so that the water depth abruptly changes. By doing so the ship avoids as much as possible
sailing with critical speed and generating dangerous waves. U.S. Pat. No. 7082355 consists of
a combination of devices that warn the captain when the ship is entering the critical regime in
relatively shallow water. A practical use of this device consists in adjusting the sailing line so that
the danger to the environment caused by vessel waves is minimized.