Radio prowords — procedure words — are standardized terms used in maritime VHF radio communication, each carrying one specific, unambiguous meaning, preventing the confusion that casual or varied phrasing could cause.
The Core Prowords
| Proword | Meaning |
|---|---|
| Over | I have finished this transmission and am inviting a reply — expect a response |
| Out | I have finished this transmission and am not expecting a reply — conversation complete |
| Roger | I have received and understood your last transmission (does NOT mean “I agree” or “I will comply”) |
| Wilco | ”Will comply” — I received your message, understood it, AND will act on it |
| Say Again | Repeat your last transmission — used instead of “repeat,” which has a different specific meaning in gunnery/naval contexts |
| Affirmative / Negative | Yes / No — used instead of casual “yes/no” for clarity over noisy radio |
| Correct / Wrong | Confirms whether a repeated-back message matches what was actually said |
Why “Roger” Doesn’t Mean “I Agree”
This is a genuinely common misunderstanding — Roger only confirms you received and understood the message. It says nothing about whether you’ll act on it or whether you agree with it. If compliance is what you mean to convey, the correct proword is Wilco. Using “Roger” when you mean “I’ll do it” is imprecise and, in a genuinely critical exchange, can create real ambiguity about whether the instruction will actually be followed.
Over vs Out: Never Used Together
“Over and out” — a phrase common in movies — is actually a contradiction and never used in real radio procedure: “Over” invites a reply, “Out” says no reply is expected. You use one or the other, never both together.
Why Standardized Prowords Matter
Casual phrasing over a radio connection — especially with background noise, accents, or a weak signal — is genuinely more likely to be misheard or misinterpreted than a small, fixed set of standardized words everyone recognizes identically. This is exactly the same reasoning behind the phonetic alphabet: removing ambiguity from a communication channel that’s inherently more failure-prone than face-to-face speech.
Exam Relevance
Correct proword usage — particularly the Roger/Wilco distinction and proper Over/Out usage — is a standard, practically-tested topic in GMDSS operator certification and deck officer competency exams.