Description
Day Shapes provide valuable information about a vessel which would otherwise be indicated by navigation lights at night. This information can help avoid collisions as well as indicate the vessel's activity or ability to maneuver.
Note that Day Shapes are not distress signals — see USCG "Navigation Rules" (Rule 27[h]) and (Annex IV), except when a round ball is displayed immediately above or below a square flag, as a signal indicating distress and need of asistance.
What follows is for educational purposes only. For the actual day shape requirements, please refer to your copy of the USCG "Navigation Rules."
Day shapes are required to be black, have certain dimensions (vessels less than 20m may use smaller shapes - refer to the "Rules"), and be displayed in a particular fashion. As with navigation lights, there are both Inland and International Rules for the display of day shapes.
All Cal June Day Shapes are manufactured from heavy-duty vinyl coated nylon fabric with stainless steel or galvanized framing. They are fully collapsible when stored. Simplicity of design offers rapid and rigid display when required to be used.
Below are some examples of day shapes and their uses:
• Single Ball - Vessel at anchor (not required on vessels less than 20 meters (65.6 ft) when anchored within a designated special anchorage)
• Double Ball (vertically) - Vessel not under command (unable to follow the Rules of the Road)
• Triple Ball (vertically) - Vessel aground or Vessel with Restricted Maneuverability
• Single Cone (apex upward) - Commercial fishing gear extends more than 150m (492 ft) from the vessel
• Single Cone (apex downward) - Vessel under sail with auxiliary power engaged
• Double Cones (apexes together; vertically) - Commercial fishing - trawling
• Diamond (double cones with bases together; vertically) - Towing where length of tow* exceeds 200m (656 ft) or placed at aft end of the tow, when tow is inconspicuous or partially submerged - like a log raft
• Cylinder (optional) - Vessel is constrained by draft
* Length of tow is measured from the stern of the towing vessel to the aft end of the towed object.