I'm amazed that none of the boats got in the way.

As I recall (it's been several years) the Coast Guard marks the
regulated area with special buoys and then patrols it industriously,
assisted by whatever boat-equipped local police can be pressed into
service. See for instance http://www.military.com/Content/More...Notice,00.html

As viewed from small craft in the spectator fleet, the wisdom of this
rule probably seems pretty obvious!

Note also that the "foreshortening" effect of a long lens makes
things seem closer to each other than they really are. The
photographer mentions using a 70-300 mm focal length zoom lens; as the
numbers go in 35mm film cameras and similar digital SLRs, that would
range from mild to quite substantial telephoto.

Cheers,
--Joe