ISO E051 Two-way VHF radiotelephone apparatus Sign

What ISO 7010 E051 Marks

E051 identifies the charging rack or locker holding the ship's portable two-way VHF radiotelephones — the handheld GMDSS survival craft radios that let people in a lifeboat or liferaft talk to the mother ship, other vessels, and rescue units. The green safe-condition sign carries a white handheld radio pictogram and marks stowage location only; it says nothing about radio procedure.

These are not ordinary walkie-talkies. GMDSS survival craft VHF sets are built to a dedicated standard: waterproof, buoyant or wearable, high-visibility, operable with cold or gloved hands, and powered by a sealed primary battery reserved for emergencies (many models take a rechargeable pack for daily on-board use, with the emergency battery kept sealed). They cover the marine VHF channels including Channel 16, the international distress, safety, and calling frequency.

The Radio's Place in the GMDSS Chain

Within the survival-equipment trio that ISO 7010 signs E047, E051, and E052 mark, the two-way VHF is the voice link. The EPIRB tells the satellite system a distress exists; the SART lets a searching radar home onto the craft; the handheld VHF is what turns the final approach into a conversation — survivors can report injuries, describe their craft, coordinate pickup order, and talk directly to a helicopter or lifeboat coxswain during the recovery itself.

It is also the on-scene communications tool before anyone abandons ship: during an evacuation, officers at the muster stations and embarkation deck use the same portable sets to coordinate with the bridge. That dual role is why the radios are stowed centrally and prominently rather than pre-distributed into the boats, and why their location deserves an unambiguous sign.

Carriage Requirements and Stowage Practice

SOLAS requires passenger ships and cargo ships to carry multiple portable two-way VHF sets as part of their GMDSS outfit, with the count scaled to ship type and size. They are typically kept on the bridge in chargers, ready for the officers to distribute at the muster list's direction. Post E051 at that stowage point, and align the marking with the ship's safety plan so surveyors can trace each required set to a signed location.

Battery management is the compliance detail inspectors check: the sealed emergency primary batteries carry expiry dates and must be in date, while rechargeable service packs need working chargers. A signage audit is a natural moment to verify both, along with the water-resistant instruction card and lanyard each set should retain. IMO Resolution A.1116(30) ties this marking, like the rest of the E-series maritime set, to the ISO 7010 symbols.

E051 and Related Communication Signage

Distinguish E051 from general emergency-telephone signage (E004 marks an emergency telephone) and from the fixed GMDSS installation on the bridge, which needs no location sign because its operators sit in front of it. E051 exists for the portable sets precisely because they must be found, grabbed, and carried by people under stress.

On passenger ships, crew drills should trace the full sequence the signs encode: muster station, E051 radios collected, E047 SART and E052 EPIRB retrieved, E048 pyrotechnics confirmed in the craft, embarkation. Walking that chain with the actual signage is a cheap, repeatable way to expose missing markings before a port state control officer does.

What is a two-way VHF radiotelephone on a ship?

A portable, waterproof handheld VHF radio built to GMDSS survival craft standards. Officers hand the sets out during abandon-ship and take them into the survival craft so survivors can communicate by voice with rescue vessels and aircraft on marine VHF channels, including Channel 16, the international distress and calling frequency. SOLAS ships carry several as part of their required radio outfit.

How is the survival craft VHF different from the EPIRB and SART?

The EPIRB (sign E052) automatically alerts rescue authorities via satellite; the SART (sign E047) makes the survival craft show up on a searcher's radar. Neither carries voice. The two-way VHF (sign E051) is the only device of the three that lets survivors actually speak with rescuers — reporting conditions, injuries, and coordinating the pickup.

Where are the portable GMDSS radios kept on board?

Normally in chargers on or near the navigation bridge, ready for officers to hand out during an emergency per the muster list, rather than stored inside the survival craft. The E051 sign is posted at that stowage point so any crew member can locate the sets, and the location should match the vessel's approved safety plan.

Why do GMDSS handheld radios have a sealed emergency battery?

The dedicated primary battery guarantees a known capacity in a real emergency, unaffected by daily use and charging cycles. Many sets pair it with a rechargeable pack for routine work; the sealed battery stays untouched, carries an expiry date, and must be replaced when it lapses — one of the items surveyors and port state inspectors routinely check.