A berth, a bridge and a radio check
You are skipper of the 12 m motor cruiser Wanderer, approaching an east-coast harbour at 14:20 on a Saturday in July. Harbour control listens on Ch12; the marina office advertises Ch80 for berthing; the lifting bridge control monitors its published working channel, Ch13. You need a visitor berth for the night and a bridge lift in 20 minutes. Your fixed VHF is on Ch16; you also have a handheld. The harbour is busy with ferries and a regatta. The set's high/low power button is on 25 W. A crew member asks you to call the marina on Ch16 because 'everyone listens there'. You also want a radio check because the antenna was reconnected yesterday. The marina is 1.2 nm away. The bridge is 0.5 nm away.
1. Which channel would you use for the marina berth request, and what is wrong with making the call on Ch16?
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Use the marina's advertised working channel, Ch80 in this harbour, for the berth request. If there is no answer, call harbour control on Ch12, which is the port operations channel for movements and local information. Ch13 is for the bridge on its published working channel, not for a general marina chat.
Ch16 is the international distress, safety and calling channel. A very short initial hail on Ch16 is acceptable if no other channel is known, but it must be followed immediately by 'change to [working channel]'. Holding a conversation about berth availability, power leads and shower tokens on Ch16 is not acceptable: it blocks the one channel every vessel is watching for a MAYDAY. Ch70 is worse - it is DSC only and must never carry voice. The crew member's suggestion is understandable but wrong.
2. Write the sequence for a radio check and explain what 'readability 5' means.
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I would use a working channel or a routine call to a station that offers radio checks, not a long test on Ch16. For example, on Ch80: 'Marina office, marina office, this is Wanderer, Wanderer, radio check, over.' The reply should be: 'Wanderer, this is Marina office, readability 5, over.' I would then thank them and clear the channel.
Readability is normally reported on a five-point scale: 1 unreadable, 2 barely readable, 3 readable with difficulty, 4 readable, 5 perfectly readable. 'Readability 5' means the signal is loud and clear, so the antenna reconnection is probably sound. A radio check should be brief, should identify the vessel and should not become a conversation. If the marina does not offer checks, a short call to the coastguard on Ch16 is acceptable in the UK, but the working channel is better etiquette.
3. You are 0.5 nm from the bridge and need it lifted. What radio etiquette and power setting do you use, and why not simply call 'Bridge, Bridge' on Ch16?
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Call the bridge on its published working channel, Ch13 here, using low power - normally 1 W - because 0.5 nm is very close and high power is unnecessary. Listen first to check the channel is clear, then say: 'Bridge control, bridge control, this is Wanderer, Wanderer, approaching from the east, 0.5 miles off, requesting a lift, over.' Give your position and intentions, not a long story.
Do not call 'Bridge, Bridge' on Ch16. Ch16 is for distress, safety and initial calling; a bridge operation is routine port traffic and belongs on the working channel. Using 25 W at 0.5 nm can also cause unnecessary interference and is poor etiquette. If the bridge does not answer after two short calls, go to harbour control on Ch12 or use the published telephone number rather than continuing to call on Ch16.