Can a disqualified boat still protest?

The Case Book for 2025-2028 (click here) complements The Racing Rules of Sailing (RRS) and provides details on the application of the rules. Here’s Case 1:

A boat that breaks a rule while racing but continues to race may protest over a later incident, even though after the race she is penalized for her breach.

Facts
Boats A, B, and C are racing with others. After an incident between A and B, A hails ‘Protest’ and displays a red flag, but B does not take a penalty. Later, B protests a third boat, C, after a second incident. The protest committee hears A’s protest against B and disqualifies B.

Question
Does the fact that B is disqualified as a result of A’s protest make B’s protest against C invalid?

Answer
No. When a boat continues to race after an alleged breach of a rule, her rights and obligations under the rules do not change. Consequently, even though A’s protest against B is upheld, the protest committee must hear B’s protest against C and, if B’s protest is valid and the protest committee is satisfied from the evidence that C broke a rule, C must also be penalized.