9.2 Survival Craft VHF (Key Topic 23)

Survival Craft VHF (Key Topic 23)

Quick Answer: A survival-craft portable two-way VHF is a watertight (1 meter for 5 minutes), simplex-voice handheld with a fixed, non-removable antenna and required Channel 16. It is not required to operate simplex on Channel 70, and Channel 13 is not a required SCT channel. Minimum effective radiated power of 0.25 W is a true equipment statement; the pool's minimum SCT transmitter power is 1 watt. The radio may talk to survival craft, ships, and rescue units.

Why this handheld is a different radio from the bridge set

The VHF on the navigational bridge is a 25-watt (reducible to 1 watt) installed station with Channel 13 bridge-to-bridge, Channel 16 distress and calling, Channel 70 DSC, Dual Watch, and a removable or mast-mounted antenna. The survival-craft transceiver (SCT) is the radio that leaves the ship in a raft or lifeboat. Element 1 tests a short, strict equipment list for that portable. If you answer Key Topic 23 with bridge habits, you will pick the distractors the pool wrote for people who confuse the two sets.

OpenExamPrep's independent Element 1 material for this topic walks the portable's required traits, the channels it must and must not claim, the two power figures, and who it may call. The chapter does not claim official FCC endorsement.

Watertight: 1 meter for 5 minutes

Survival-craft portable two-way VHF must be watertight to a depth of 1 meter for 5 minutes. That is a construction requirement, not a suggestion to dunk the radio for fun. Abandon-ship is wet. The handheld will be sprayed, dropped into the well of a raft, and handled with soaked gloves. The 1 m / 5 min figure is the pool's watertight statement. “Watertight” also appears as one of the required characteristics bundled with Channel 16 and a permanently affixed antenna.

Do not upgrade the number in your head to “submersible to 10 meters” or shrink it to “splash resistant.” Write 1 meter for 5 minutes.

Simplex voice only — not a DSC handheld

Equipment for this service is simplex voice communications only. Simplex means both stations transmit and receive on the same frequency, one at a time, so every station in range hears both sides. That matches distress and on-scene voice practice.

What it is not:

• It is not required to operate simplex on Channel 70. Channel 70 is the VHF DSC-only channel (156.525 MHz). Survival-craft portables in this key topic are voice sets. A statement that the SCT “operates simplex on Ch-70 and at least one other channel” is the untrue statement in the pool's first “which is NOT true” item.
• It is not a semi-duplex public-correspondence radio. You are not placing telephone calls from the raft on a paired shore channel as the primary design case.

If a choice mixes DSC Channel 70 into the survival-craft handheld's required capabilities, treat that mix as false for Key Topic 23.

Channels: Channel 16 is required; Channel 13 is not

Operation on Channel 16 is required. Equipment for radiotelephony use in survival craft stations under GMDSS must have Channel 16 capability. That is the international distress, safety, and calling voice channel (156.800 MHz). After abandon-ship, that is how you call the mother ship, another ship, or a rescue unit that is already on scene.

Channel 13 is not a required survival-craft channel. Channel 13 is bridge-to-bridge navigational voice in most U.S. waters. The raft is not keeping a navigational watch. A statement that the portable must operate on Channel 13 is the untrue statement in the pool's second “which is NOT true” item. The true companions on that list are 0.25 W minimum ERP, simplex voice, and Channel 16 — so the false extra is Channel 13.

Other frequencies that show up as capability distractors include 457.525 MHz and 121.500 MHz. Aircraft distress voice is 121.500 MHz A3E — that is a different service, taught under VHF channel selection, not a required SCT capability. When the pool asks what capability GMDSS survival-craft radiotelephony equipment must have, the answer is operation on Channel 16, not “any of those other frequencies.”

Channel 16, Channel 70, and Channel 13 on one comparison line

Keep this three-way split in working memory:

• Channel 16 — required SCT voice channel.
• Channel 70 — DSC only on an installed GMDSS station; not a required SCT simplex voice channel.
• Channel 13 — bridge-to-bridge on the ship; not a required SCT channel.

That split is the whole channel half of Key Topic 23.

Antenna: fixed and non-removable

The survival-craft VHF antenna is fixed and non-removable (also stated as a permanently affixed antenna). Survivors are not expected to thread a separate whip onto a wet connector in the dark. A removable antenna is a failure point: it gets dropped, it is missing from the bag, or the connector floods. The required design is a permanently attached antenna.

Do not import the SART height lesson onto this antenna. You can hold the radio up, but you do not unscrew the antenna to mount it on a pole. The SART is the unit you raise as high as possible. The SCT keeps its antenna attached.

Two power figures: 0.25 W ERP and 1 watt SCT power

Key Topic 23 uses two different power statements. Learn both. Do not collapse them into one number.

Minimum effective radiated power (ERP) of 0.25 watts is a true pool statement. It appears among the true characteristics in the “which statement is NOT true” items. The untrue claims on those items are Channel 70 simplex operation and Channel 13 operation — not the 0.25 W ERP sentence. If a question lists 0.25 W ERP next to watertight construction and a fixed antenna, treat 0.25 W ERP as true.

The minimum power of the SCT is 1 watt. That is a separate, direct pool fact. Distractors are five watts, one-quarter watt as the only figure, or “none of the above.” When the item asks for the minimum power of the SCT, the answer is one watt.

How to keep them from fighting in your head: 0.25 W ERP is a true effective radiated power minimum used in the true/false equipment lists. 1 watt is the minimum SCT transmitter power when the question asks for SCT power by name. Both sentences are true in the pool. The exam will tell you which quantity it wants by the wording — ERP in a characteristics list, or “minimum power of the SCT.”

Bridge VHF must be able to reduce to 1 watt for short-range work. That 1-watt reduce-power rule and the 1-watt SCT minimum are easy to mash together. They are related in magnitude and still different rules: one is a low-power capability on an installed 25-watt set; the other is the survival-craft handheld's minimum power.

Who the handheld may call

Portable survival-craft transceivers may communicate with:

• Survival craft (raft to raft, boat to boat),
• Ships (including the abandoned vessel and other vessels), and
• Rescue units (coast guard boats, helicopters on a marine VHF, other SAR craft).

The correct completeness answer is all of the above. The radio is not limited to intra-raft chatter, not limited to the mother ship, and not limited to a single designated rescue unit. On-scene SAR voice is messy and multi-station. Channel 16 simplex is how those stations meet.

A practical picture: two rafts from the same ship call each other, then call the ship if it is still afloat, then answer a responding cutter. One handheld, three permitted counterparts, same channel plan.

Bundled GMDSS characteristics

When the pool bundles characteristics for radiotelephony equipment in survival craft stations under GMDSS, the true bundle is:

• Operation on Channel 16,
• Watertight construction, and
• Permanently affixed antenna.

All of these is the completeness answer. You will also see the watertight depth/time (1 m / 5 min), simplex voice, fixed non-removable antenna, and 0.25 W ERP restated as individual true lines. The false extras to mark as “NOT true” are Channel 70 simplex and Channel 13 operation.

Survival-craft VHF requirements versus common mix-ups

Using the handheld once you are in the raft

Turn it on, confirm Channel 16, keep the antenna vertical, and listen before you transmit — the same listen-before-talk habit as any maritime voice circuit, except distress. Identify the survival craft and the parent vessel, give position if you have it, and say how many people are in the raft. You are not running a public-coast working channel from the canopy. You are running on-scene voice.

Conserve the battery once contact is made. The SART (Key Topic 22) keeps painting radar while you are quiet. The EPIRB (Key Topic 21) keeps the satellite alert alive. The handheld is the voice layer. Key Topic 23 does not ask you to quote a battery-hour figure; it asks you to know what the radio is — watertight, simplex, fixed antenna, Channel 16, 0.25 W ERP as a true minimum-ERP statement, 1 watt SCT power, and permission to talk to craft, ship, and rescue unit.

If you remember only one negative and one positive, remember these: not Channel 70, not Channel 13; yes Channel 16. Then attach the physical facts (1 m / 5 min, fixed antenna, simplex voice) and the two power figures (0.25 W ERP true; 1 W SCT minimum). That is the entire portable.