In our local area (San Francisco Bay and the Sacramento & San Joaquin River deltas) there are numerous exclusion areas around various areas. I used to define these as "Not Navigable". If you sail into some of those, an armed patrol boat will stop you and may arrest you. Pretty clear that this is a legitimate use of the term Not Navigable, as it is closed by US Government order.

The St Francis YC standard language for SIs is below. The Race Committee has chosen to declare these areas and others "obstructions", and to expand the coverage to include all time periods before, during, and after racing. This wording has worked well so far.

A recent SI:
"7.1. Any line bounded by the following points is designated as an obstruction. Boats are prohibited from crossing

- The “H” Beam piling and the closest point ashore -located approximately 200 yards west of StFYC (d)"

Think this one deserves its own thead to get folks opinions. Standby. 

You have made me realize that I spend too much time practicing starts, and not enough time practicing finishes.

Yes John, I agree. I meant there may be no reasonable opportunity on some courses and so there seemed to be some suggestion that the protest needed to be raised before the NSC boat crossed the finishing line and I was merely trying to say that couldn't always be possible.