Did you know ...

#17: How to model open deck wells

Open wells on the deck of displacer parts take on water at the level of the external waterline like flooded tanks, regardless of whether these wells appear to be protected by deck edges that are above the waterline. This can be clearly visualized in Condition Graphics by looking at a body view that cuts through the open well.

However, often it is desired instead for water to enter an open well only when the external waterline reaches the well's perimeter on the deck. This can be accomplished using the following method:

1. In Part Maker, create a new tank part (say, OPENWELL.C) with the dimensions of the open well, and remove any corresponding open well deduction from the displacer part.

2. Create a series of critical points that are appropriately spaced around the perimeter where the open well intersects the displacer deck. If this perimeter is roughly shaped like a polygon (such as a rectangle), then a critical point at each vertex would be sufficient. These points can be created using the CRTPT command either in Part Maker when the vessel tanks are modeled or later in GHS. In either case, be sure to include the CRTPT /TANK:OPENWELL.C parameter when defining each critical point to associate it with the open well tank.

3. In GHS, set the open well tank to damaged with sea contents using the commands:

CONTENTS (OPENWELL.C) SEA
TYPE (OPENWELL.C) DAMAGED

By associating the perimeter critical points with the damaged open well tank, its reference point for damage will be dynamically assigned to the lowest critical point along the perimeter of the open well. This produces the desired behavior of keeping the open well dry when the external waterline is below the well's deck perimeter, otherwise flooding it to the level of the waterline.

More information can be found at HELP CRTPT and HELP PM in the "Critical Point Specification" section. GHS version 11.94 or later is required to access this feature. For help updating your GHS version, please contact support@ghsport.com.