SMS:ADH Vessel Coverage

The ADH Vessel Coverage is used to add vessels to the simulation and give them paths to follow. Generally, one coverage represents one vessel. A user can drag one or more vessel coverages into the ADH Mesh to add those coverages to the simulation (by creating links). This allows a user to have more vessels defined than they are using in the simulation, and they can swap them in and out of the simulation to run different tests with different vessels.

Boat Path

Each vessel coverage has at least one arc to define the boat path. The arc determines the vessel's starting position and starting speed, and where it will go from there. Additional segments can be added to the arc by adding vertices. Vertices add destinations but do not affect speed. To change the speed of the boat, convert a vertice into a node, and enter the node's attributes.

In general, there will always be exactly one path per vessel coverage. The path can be made up of multiple arcs, but the arcs should not split into multiple paths. The one exception to the rule of "one path per coverage" is when there are multiple vessels that are identical except for their speeds and paths. In this case SMS can have multiple separate paths in the same coverage, and each will create its own separate copy of the boat defined in the coverage properties. These paths can cross each other as long as they do not connect to each other (at a node). Another option is to simply duplicate the coverage after the boat properties are defined. This allows adding and removing the boats from the simulation separately, and the boats can have vertices and nodes in the same place (same x and y coord) along their path without conflicting. The boat path writes the FDEF and SDEF cards to the boat file.

Dialogs

Node Attributes

Nodes on arcs change the speed of the boat or, in the case of the first node of the path, define the boat's starting speed. To change the speed of the boat at a node, select it and right-click, then select Node Attributes.... Alternately, a user can double-click the node.

File:ADH Vessel Node Att.jpg

ADH Vessel Node Properties dialog

Boat Parameters

File:ADH Vessel Att.jpg

ADH Vessel Attributes dialog

The boat's parameters are defined in the coverage properties. Right-click on the coverage and choose Properties.... This dialog lets the user set the boat's size and shape, and define propellers if desired. If the OP BTS card is included, each vessel in the simulation will need to have propellers defined. Without the OP BTS card, propellers supposedly do nothing.

Each field corresponds directly to a card in the boat file.

• Length (BLEN)
• Width (BWID)
• Bow to Length Ratio (PBOW)
• Stern to Length Ratio (PSTR)
• Draft (DRFT)
• Fraction of Draft Applied to PBOW (CBOW)
• Fraction of Draft Applied to PSTR (CSTR)

Propeller (PROP card):

• Propeller Type: Open wheel or Kort nozzle
• Propeller Diameter
• Distance between propellers
• Tow boat length: This length provides an offset distance of the propeller induced shear stresses from the vessel. Set to 0 if there is no tow boat.
• Distance from prop to tow boat stern

Related Topics

• ADH