Ikari-ing(Risk Assessment Application for Dragging Anchor)
- "Risk Assessment Application for Dragging Anchor"is a system which simply estimates risk level of dragging anchor while anchoring based on the basic ship information (ship types/principal particulars) and the marine weather forecasts.
A ship anchored in rough weather is subject to wind pressure forces from strong winds and wave drift forces from rough waves and swells. In addition, fluid reaction forces (maneuvering hydrodynamic forces) produced by ship motion and fluctuating tension of the anchor chain caused by the ship's movements may also contribute to violent slewing motion.
The IKARI–ing simulation program calculates risk of anchor dragging by taking into account the above–mentioned external forces acting on the ship (wind pressure forces, wave drift forces, anchor chain tension, and maneuvering hydrodynamic forces) to estimate the swing motion.
For maneuvering hydrodynamic forces and wave drift forces, IKARI–ing's estimation method applies experimental results obtained from water tank testing using model coastal tankers and coastal ferries, two representative types of non–international coastal trading vessels. Wind pressure forces are estimated using a method proposed by the National Maritime Research Institute (NMRI). For anchor chain shape and tension, an estimation method that calculates the static catenary is used.
IKARI–ing was developed by NMRI as part of research commissioned by the Ministry of Land, Infrastructure, Transport and Tourism (MLIT)'s FY2020 supplementary budget project "Emergency Measures to Prevent Anchor Dragging Accidents."
In the Input Interface screen, you can choose between Simple Mode, which has reduced input parameters, and Advanced Mode, which performs the same calculations as the PC version. In the Output Interface screen, you can view the risk level of anchor dragging for the input values and the change in risk of anchor dragging depending on different lengths of extended anchor chain and wind speeds. IKARI–ing (Web Application Version) executes simulations in the cloud and can be used on any smartphone regardless of its technical specifications.
Main screen
Input Interface: Simple Mode
Input Interface: Advanced Mode
Output Interface
Main screen
First, tap "Start Risk Assessment Application for Dragging Anchor" on the Main screen.
Terms of Use Acceptance screen
A screen displaying Terms of Use appears. Read the Terms of Use.
Terms of Use
It is necessary to accept the Terms of Use in order to use the Risk Assessment Application for Dragging Anchor.
Terms of Use Acceptance screen (after selecting the "I Agree..." checkbox)
Select the "I have read and accepted Terms of Use" checkbox to accept the terms of use. Then tap "Forward to Risk Assessment Application for Dragging Anchor" to proceed to the Input Interface screen.
Input Interface: Simple Mode
Compared with Advanced Mode, Simple Mode has reduced parameters. This allows you to quickly assess risk level of anchor dragging.
Initial Configuration screen
First, start initial settings.
Select Ship Type from the pull–down menu. If the applicable ship type is not listed, select ship type whose shape is the most similar to your ship's.
Next, select the value for Gross Tonnage from the pull–down menu. If you are unsure about the ship's gross tonnage, select the amount that seem to be the closest to your ship.
Initial Configuration screen
After selecting Ship Type and Gross Tonnage, tap the "Apply" button.
Ship information screen
IKARI–ing automatically fills in parameters for the ship information, projected area of the wind pressure forces, and anchor chain information. Confirm the automatically filled parameters and correct any values that differ from your ship's information.
Anchorage Information screen
You have input all ship parameters. Next, input parameters related to anchorage information, weather and sea state information, and ship conditions.For Anchorage Information parameters, select Sea bottom sediment (Sand or Mud) and the Anchoring Method (Single anchor mooring or Twin–anchor mooring)
Weather & Sea State Information screen
You can use the Simple Estimation function for the Wave Period parameter in weather and sea state information. If you are not sure about the wave period in anchorage, select the Simple Estimation checkbox. IKARI–ing will automatically calculate the Wave Period for you. Note that the estimated Wave Period assumes the wave period during rough weather conditions, such as during a typhoon.
Ship Conditions screen
In the Ship conditions, enter the ship's draft and heading.
"Calculate" button
After you have input all parameters, tap the "Calculate" button. The parameters are validated.If corrections are not needed, the "Calculating..." message is displayed.
Error message
If there are invalid parameters, a warning message and the invalid parameters are displayed. Correct the parameters as instructed by the warning.
Calculation in progress message
Input Interface: Advanced Mode
First, start initial settings.
Select Ship Type from the pull–down menu. If the applicable ship type is not listed, select ship type whose shape is the most similar to your ship's.
Next, select the value for Gross Tonnage from the pull–down menu. If you are unsure about the ship's gross tonnage, select the amount that seem to be the closest to your ship.
Initial Configuration screen
After choosing Ship Type and Gross Tonnage, tap the "Apply button. IKARI–ing automatically fills in parameters for the ship information, projected area of wind pressure forces, and anchor chain information. Confirm the automatically filled parameters and correct any values that differ from your ship's information.
Input ship information
Surface Area Affected by Wind Force (Fully Loaded Hull)screen
Anchorage Information screen
You have input all ship parameters. Next, put parameters related to anchorage information, weather and sea state information, and ship conditions.
Anchorage Information screen
For Anchorage Information parameters, select the Sea bottom sediment (Sand or Mud) and the anchoring Method (Single anchor mooring or Twin–anchor mooring )
Weather & Sea State Information screen
Ship Conditions screen
In the Ship conditions, enter the ship's draft and heading.
"Calculate" button
After you have input all parameters, tap the "Calculate" button. The parameters are validated.
Error message
If there are invalid parameters, a warning message and the invalid parameters are displayed. Correct the parameters as instructed by the warning.
Calculation in progress message
Risk level of anchor dragging
After calculation is completed, the Output Interface screen is displayed. The risk of anchor dragging at one of three levels — High, Medium, or Low — is displayed. Also displayed is a graph showing the change in risk of anchor dragging depending on different length of extended anchor chain or different wind speeds.
Risk of anchor dragging for different lengths of extended anchor chain
Tap the graph name to switch between the two graphs.
Risk of anchor dragging for different wind speeds
Warning message if the anchor dragging risk is high
The bottom of the risk of anchor dragging assessment results shows the input parameters and warning message if the risk of anchor dragging is high.
Input parameters
"Return to Input Parameters" button and "Return to Menu" button
If you wish to update the input parameters and recalculate the risk, tap the "Return to Input Parameters" button.
Single anchor mooring(Possible to select)
- Anchor can be weighed easily for quick anchorage changing.
- Easy to switch to other anchoring method such as steady anchor or twinanchor mooring according to the wind direction change.
- The anchor holding is weaker than other anchoring methods.
- Source of reference
Japan Coast Guard Guidelines for preventing anchor dragging
Twin–anchor mooring(Possible to select)
- The effect of reducing yawing/swaying is highest when anchor chain angle is set to 45-60 degrees and the force on the anchor will be reduced by nearly 40%.
- Anchor may foul by the wind direction changes.
- Fouled chain is difficult to fix on ship's own.
- Weighing of anchor is difficult in the strong wind.
- Source of reference
Japan Coast Guard Guidelines for preventing anchor dragging
Single anchor mooring with snubber anchor(Not possible to select)
- Effective to reduce bow yawing/swaying.
- The snubber anchor is effective to reduce yawing/swaying by halves and to reduce the force on the anchor by 30–40%.
- Effective in sea areas where wind is not very strong.
- Anchor may foul by the wind direction changes.
- Fouled chain is difficult to fix on ship's own.
- Weighing of anchor is difficult in the strong wind.
- Source of reference
Japan Coast Guard Guidelines for preventing anchor dragging
Two–anchor mooring(Not possible to select)
- Anchor holding is enhanced.
- Effective in strong wind and current from the same direction.
- Anchor may foul by the wind direction changes.
- Fouled chain is difficult to fix on ship's own.
- Weighing of anchor is difficult in the strong wind.
- Source of reference
Japan Coast Guard Guidelines for preventing anchor dragging
Tap the Install banner.
Tap "Install."
The IKARI–ing app icon is displayed on the Home Screen.
Tap the browser's Menu button.
Tap "Add to Home Screen."
Tap "Add."
The IKARI–ing app icon is displayed on the Home Screen.
For instructions on how to use IKARI–ing (PC Version), refer to the PC version download site or the instruction manual included with IKARI–ing (PC Version).