Mold Line First

In cases where the mold line is defined first, the mold line can either be defined by a line directly or as a line parallel to a limit of the panel (or to a line).

<mould_line_first>::= <mould_line><end_point_1>/<end_point_2>

Below, we treat the definition of the mold line first and then how to define the end points, once the mold line is known.

A. Mold line definition

The mold line can be defined, either along a given line or as being parallel to a limit or a given line.

<mould_line>::= <line_direct> | <line_parallel>

<line_direct>::= ,<line> (1 ... 25) [,REV]

This makes sense only if any of the end points end against the outer contour.

By adding an extra line, intersecting the limit, the stiffener will be set parallel to the tangent in the intersection point.

Otherwise, the stiffener will be set parallel to the longest straight segment of the limit.

To summarize: The mold line can be defined in one of the following ways:

1. Along a given line.

   

2. Parallel with and at given distances from a line.

   

3. Parallel with and at given distances from (the longest straight part of) a limit.

   

4. Parallel with and at given distances from the tangent to a given limit in the intersection point with a given line.

   

B. Definition of the end points

Once the mold line is defined, the end points can independently of each other - be defined in a number of different ways:

• by attachment to a stiffener/flange on the panel

• by the intersection with a given line

• by the intersection between the mold line and the outer contour.

• by connection to the surface of a given intersecting panel.

• by connection to the surface of a bracket on the same panel.

• by "connection" to a hole in the same panel.

• by "connection" to a seam in the same panel.

  <end_point_1>::=	CON = <con_code>
  	[, <int_prof_ref> |
  	<line_1> |
  	<name> [,REFL] |
  	<bracket_ref> |
  	<hole_ref> |
  	<seam_ref> ]
  CON	is the connection code according to the Design Standards.
  	<con_code>::= <integer>
  <name>	Name of an intersecting panel, to the surface of which the stiffener should be attached. It may be mirrored in the CL plane by adding the keyword REF.
  <int_prof_ref> <line_1> <bracket_ref> <hole_ref>	See General Layout of a Statement.

If not defined by a given profile, line or any other explicitly given item, the stiffener is supposed to end at the outer contour. Depending on the connection type this may be done as though the stiffener were connected to a stiffener along the tangent of the outer contour in its intersection point with the mold line (see the image below).

As an alternative, the stiffener may be connected to the surface that bounds the panel where its outer contour is intersected by the mold line of the stiffener, or it may be connected end-to-end with a stiffener on another panel bounding this panel.

Conditions for the latter cases are:

• a connection code for surface connection has been used, and a hull curve (or panel) has been used for the corresponding boundary.

  or

• a hull connection code for end-to-end connection has been used and a panel has been used for the corresponding boundary.

  <end_point_2>::= <end_point_1>

  However, in <end_point_2>, <line_1> is replaced by <line_2>.

The formal description above means that any of the end points can be defined in one of the following ways:

5. Attach to another stiffener or flange on the current panel. An appropriate connection code must be supplied to define the detailed shape of the connection.

   

6. Intersect the mold line with a given line. A connection code is accepted but does not affect the result.

   

7. "Attach" the stiffener to a "fictitious" stiffener along the tangent to the outer contour in its intersection point with the mold line. Connection code must be supplied.

   Depending on the connection type (see above) the "tangent line" may be replaced by the "tangent plane" of the boundary, for example, of the hull surface.

   In the former case, the end cut angle of the web will normally be 90 degrees and clearance (if any) will be calculated along mold line.

   In the latter, the web angle may have any value and the clearance will be perpendicular to the surface.

   (If any of the end points has been generated according to this alternative, the given direction of the mold line must be that of the stiffener when generated. In other cases, the direction is irrelevant - Hull Modelling will select the correct direction automatically.)

   

8. Attach the stiffener to the surface of a given panel. The connection will be done, as in case 1), to a fictitious flat bar in the location of the panel.

9. Attach to the surface of a given bracket on the panel itself. The connection will be done as in case 4).

10. Attach to a hole on the panel itself. The connection will be done in the same way as to a flange welded to the edge of the hole.

    Below, a number of examples defined according to the syntax for 'mold line first' are given. In some of the examples, the end cut data are left out.

    In the examples 1 and 2, the direction of the given line can coincide with or be opposite to the final mold line, since both end points are explicitly defined.

Example 1 ('line direct'):

Example 2 ('line direct'):

Example 3 ('line direct'):

Example 4 ('parallel to limit'):

Example 5 (see Example 4 - Note: LIM > 0):

Example 6 ('parallel to limit'):

Example 7 ('parallel to limit' - see image above):

Example 8 ('parallel to limit'):

Example 9 ('parallel to line'):

Example 10 (along line between bracket and hole):