Whilst traveling on the ferry from Cowes to Southampton after the
firwork display, I noted the frequent use of flashing lights on
vessels under way. Two categories stood out:

a. Fast ferries (not aircushion vehicles) used a rotating yellow
strobe above their masthead lights.

b. Several RIBS, mostly around 6m - 10m length, displayed rotating
blue strobe lights below their masthead lights.

So far, I was only aware that flashing lights were permitted for
air cushion vehicles (quite sensible, because they don't
necessarily travel in the direction they're pointing - so other
navigators need to be aware of this when interpreting their
navigation lights), and for purse seine fishing vessels working in
close proximity. Otherwise, colregs seem to forbid the use of
flashing lights.

Does anyone know when or by what instrument the colregs were
amended for the Solent?
--
JimB
http://www.jimbaerselman.f2s.com/
Describing some Greek and Spanish cruising areas