Developing of Dynamic Under Keel Clearance (DUKC)
Fundamental importance of seaports in
different aspects, especially in developing a nation’s economy, cannot be
repudiated. Since seaports make a notable contribution to economic development
of countries, senior managers devote scrupulous attention for seeking methods
to promote efficiency in the overall transport chain. Of the significant parts
of promoting efficiency in ports is boosting navigational safety which can be
reachable by either hardware or software approach. Regular dredging of approach
channels and human resource training or employing well-established
computational methods for managing safe transport in ports can be considered as
hardware and software methods, respectively.
The current project aims to use a software
approach whose goal is to calculate under keel clearance by considering most
environmental conditions. Therefore, not only the ship's safety is guaranteed when entering and exiting the harbor, but also it is
possible to let vessels having greater draft move in shorter time intervals, promoting
transport efficiency in ports. The port of Bushehr located in the Persian Gulf
is considered to implement this engineering system.
A decision-making process for a ship arriving
at or departing from a port should take place by considering three crucial
factors. The first one is arrival or departure time of vessels. Since tidal
effects making a major contribution to vessels’ transport can be regarded as a
function of time, this factor is generally taken into account as the
particularly significant one for each arriving and departing ship. The second
factor is ship’s draught, directly depends upon loading conditions of a given
vessel. The last one is the ship’s speed through the water. Although increase
of the vessel’s speed leads to decrease of UKC due to the squat phenomenon, it
is beneficial in the areas of the access channel covered by fluid mud layers,
inhibiting the ship from grounding. It is noteworthy that since controlling
vessels moving at slow speed is not feasible, vessels’ speed through the water
should not be under a specified limit.
Four plausible scenarios can be constructed
for organizing this maritime engineering system by considering three factors
including time, ship draught and speed for a given vessel.
all aforementioned factors, the user investigates the possibility of a safe
system investigates the safe arrival (departure) time for the vessel, after the
user specified the ship draught and speed.
system gives the safe ship draught for arrival (departure) in (from) the port,
after the user specified the speed and time.
system gives the safe vessel’s speed for arrival (departure) in (from) the port,
after the user specified time and ship draught.
The calculations based on which the final
suggestion will be made for decision-making are performed with both the short
time scale (less than 72-hour) and the long time scale (more than 72-hour). In
the long time scale calculations, effects of bed forms, water level, tidal
speed and squat will be taken into account. These terms are the most important
ones for estimating under keel clearance, referring to the results of the
previous research. In the short time scale, in addition to the aforementioned factors,
the effects of wave, wind and wind set-up will be also considered.
Before the launch of the project, applying
soft-computing methods was considered for calculating the aforementioned
parameters. The reason behind this decision, except for their high computational
speed, was on the assumption that we have comprehensive data available. However, after beginning
of the project and gathering data, it was found that there were not extensive data available, especially for modeling
wave characteristics. Further, if the models were set up carefully,
computational time can be tremendously reduced. Hence, for obtaining the
results, usual simulations were conducted.