1 Activate Your Free Trial!  Yawl. Yawl, two-masted sailboat, usually rigged with one or more jibsails, a mainsail, and a mizzen. In common with the ketch, the forward (main) mast is higher than the mizzenmast, but the mizzenmast of a yawl is placed astern of the rudder post, while that of the ketch is closer amidships.
System design is documented in the System Design Document (SDD). It describes design goals set by the project, subsystem decomposition (with UML class diagrams), hardware/software mapping (with UML deployment diagrams), data management, access control, control flow mechanisms, and boundary conditions.
A system project comes to a critical point when the complete new system is described in a System Design Specification or SDS. This is the time when management can be told enough about the project to make a go/no go decision. The System Design Specification provides the input into management's decisions.