Folks, please, when considering IRPCAS, look carefully at the Definitions in Rule 3.  Just like the RRS, IRPCAS rely on Definitions, but in IRPCAS, defined terms are not distinguished in the text by italics or bolding, and many of the defined terms are phrases that look like simple phrases having their ordinary english meaning , when the definition is quite precise and restrictive.

Also, by the nature of IRPCAS, the Steering and Sailing Rules with respect to vessels not under command, restricted in their ability to manoeuvre, constrained by their draught and so on, are independent of the Lights and Shapes Rules with respect to those vessels, in much the same way as RRS 17 is independent of RRS 11.

For example a vessel that meets the criteria of Rule 3(f) as being not under command, does not cease to be not under command because she is not displaying the lights or shapes required by Rule 27(a).

Another vessel that did not keep out of the way of a vessel not under command, but not displaying the required lights or shapes would nevertheless be in breach of Rule 18, although her blameworthiness would be reduced by the failure to display the required lights or shapes.

Matters under IRPCAS nearly always result in shared blame and apportioned damages.

There's an evolving mass of information about the obligations of and with respect to unmanned vessels, this FAQ from the IMo may give you some ideas:  https://www.imo.org/en/mediacentre/hottopics/pages/autonomous-shipping.aspx

In response to Charlie's OP questions

The mark bot:

IRPCAS Rules 13, 16, 17, 18(a), Rule 34(d).

The mark bot does not meet the requirements of the definition of vessel not under command.  It is NOT not under command.  A sailing vessel is NOT required to keep out of the way of the mark bot unless overtaking.

Five short blasts if in doubt as required by Rule 34(d)

Angelo -- 

The mark referenced in 7.1.1.(d) is the "B" (or Bellingham) mark about 80 ft. from the rock seawall. It is not a starting mark; that is typically the "A" mark, about 150' offshore to the north, and a placard that is displayed on the Clubhouse Race Deck as the southern end. The Race Deck end of the line is where the Race Committee views the starting line. As you know, we have such regular westerly winds that we can use this start/finish line 40 to 50 times a year for all sorts of starts and finishes. For example, it is the traditional finish line for the Rolex Big Boat Series.

The "obstruction" is almost always either on the starting line or within 20-30 feet of it, depending on the tide and the associated movement of the marks due to current. We added the obstruction to the long list of other obstructions in our SIs because competitors would occasionally run aground during starts, causing significant damage. During a start, it is now common for the southernmost competitor to hail for room on this obstruction, forcing a significant percentage of the fleet to tack away.

I think this obstruction, while not at one end of the starting line, is closely related for this discussion.

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.