VHF marine radio is "line of sight" — what is the approximate range of a 25W VHF between a yacht and HM Coastguard station on a cliff?

A. 200nm — VHF bounces off the ionosphere in good conditions

B. Exactly 25nm — one nautical mile per watt is the standard formula

C. 25–40 nautical miles typically — VHF range depends on antenna height above sea level on both ends, not transmit power. A Coastguard antenna at 50m ASL extends range significantly

D. 5nm maximum — VHF does not propagate over water effectively

A. To operate the radar system remotely

B. To broadcast weather forecasts to other vessels

C. To make telephone calls from the vessel to shore

D. To send a digitally coded distress alert containing the vessel's MMSI and position automatically to all DSC-equipped stations and the Coastguard

A. Maritime Mobile Service Identity — a unique 9-digit number identifying the vessel; without it a DSC distress alert cannot identify the vessel to rescuers

B. A GPS waypoint identifier used in coastal navigation

C. A VHF channel number allocated by Ofcom for distress use only

D. A vessel survey certificate number required by the MCA