On portable courses, the BBYRA is using an INITIAL MARK (IM) located to windward of the starting area. Boats must leave this mark to port prior to assuming the posted course. The initial mark will be placed approximately 100-200 yards to the right of the first portable mark. See Diagrams.
If a SHORT LEEWARD MARK is used it will be a yellow tetrahedron with a black band placed to windward of Mark 3.
Note particularly SI 7.3, 11.2, 25, 26, 27 & 28