There are various means available for small vessels to communicate distress to search and rescue (SAR) authorities; each method has different capabilities that are outlined in general below. It is important to note that relying on a single means of communication can be problematic because distress equipment may fail, become damaged, or become inaccessible in an emergency. Note also that there are various other types of equipment that can be used to signal distress on a local scale.Government of Canada, C.R.C., c. 1416, Collision Regulations, Schedule 1, Annex 4.
Radiotelephones
There are three primary types of radiotelephones: very high frequency (VHF), medium frequency (MF), and high frequency (HF). Each type operates on a different frequency band, has a different range and can be used to communicate with coast stations and other vessels within range.
Most modern radiotelephones include a digital selective calling (DSC) feature that allows users to send a digital distress signal quickly by pressing and holding a button for at least five seconds. A distress signal sent by DSC will repeat until it is acknowledged. The functional range for DSC is typically 25% further than voice communications due to the elimination of squelch on the receiving radio. Radiotelephones must be programmed with a maritime mobile service identity (MMSI) number in order for DSC to function as intended. Radiotelephones rely on manual activation, which may not be possible in emergencies where those on board are incapacitated or must rapidly abandon the vessel.
- VHF radiotelephones can be fixed or portable devices. The typical maximum range for voice communications sent over a fixed VHF is between 10 to 60 nautical miles (NM) depending on factors such as the available power and height of the antennae. The maximum range for portable VHF radiotelephones is significantly less at 5 to 15 NM.
- MF radiotelephones are fixed devices that typically have a maximum range of 100 to 150 NM. The range is generally greater at night.
- HF radiotelephones are fixed devices that typically have a maximum range of several hundred NM. The range varies depending on the time of day and season.
Emergency position-indicating radio beacons
Emergency position-indicating radio beacons (EPIRBs) are typically mounted on a vessel. Some models are designed to float free and activate automatically when submerged to a depth of 4 m. These models can be activated manually as well. Some EPIRB models can only be activated manually while other models do not float free. EPIRBs transmit distress signals through a satellite system to SAR authorities for at least 48 hours after activation. The transmission can be used by SAR vessels and aircraft to home in on the location of the EPIRB. EPIRBs, when registered with the Canadian Beacon Registry,National Defence, Canadian Beacon Registry, at https://cbr-rcb.ca/cbr/presentation/other_autre/index.php (last accessed 10 January 2025). provide SAR coordinators with information about the vessel, such as an emergency contact, that helps facilitate an effective response. Where an EPIRB is mounted on a vessel can be critical—if an EPIRB becomes damaged from a fire or other incident or is prevented from floating free because it is stored in a locker or trapped, it may not function as intended. It is also important that EPIRBs be mounted in locations that protect them from the elements and from accidental activation.
Personal locator beacons
Personal locator beacons (PLBs) are small waterproof devices that are designed to be worn by a person. They have a simple design whereby a person presses a button to transmit a distress signal through a satellite system directly to SAR authorities. The signal will transmit for at least 24 hours. Like EPIRBs, PLBs should be registered with the Canadian Beacon Registry.Ibid. PLBs are not necessarily designed specifically for maritime environments, so they often do not float.
Commercially available satellite communication devices
There are various commercially available satellite communication devices, from satellite messengers to satellite phones, that can be used to communicate distress. These devices work on commercial satellite systems and have wide coverage, in some cases worldwide. Satellite messengers typically allow a person to transmit a distress message to a third-party response centre that then shares the information with SAR authorities. Satellite phones can be used to call SAR authorities directly.
Satellite communication devices are not registered with SAR authorities and are usually subscription based. In addition to distress alerting, these devices may include tracking and text messaging. Features that allow for distress calls may not function without an active subscription.
Cellphones
A cellphone may be used to communicate distress by calling SAR authorities, but only if it has service. If 911 is called, the call will be transferred to the appropriate SAR authority.Some cellphone manufacturers provide a limited ability to transmit a 911 message as a distress signal by satellite when a cell tower is not available. Alternatively, with many carriers, dialing *16 will connect a caller directly to the nearest Marine Communications and Traffic Services (MCTS) centre. At sea, cellphone service may reach a maximum of 16 to 30 NM from shore, depending on the characteristics of the nearest cell tower. However, many regions of Canada do not have optimal cellphone coverage; there may not be cell towers nearby or the cellphone signal may be obstructed by the geography.
In 2024, cellular airborne sensors were installed on some SAR aircraft.National Defence, Cellular Airborne Sensor for Search and Rescue (CASSAR), at https://www.canada.ca/en/department-national-defence/corporate/transparency/access-information-privacy/privacy-impact-assessment/cellular-airborne-sensor-for-search-rescue.html (last accessed 10 January 2025). If such an aircraft is within range of a cellphone, the rescue crew can detect its location and text or call the phone. This is only possible if the phone number is known and the phone is capable of sending and receiving calls.
Sail plans
A SAR response differs depending on whether a vessel is in distress or in potential distress, or if it is uncertain whether the vessel needs assistance or not. In cases of distress (e.g., an EPIRB signal is received) or potential distress (e.g., a vessel is overdue at its destination), SAR coordinators have the authority to deploy resources to search for the vessel. Otherwise, SAR coordinators continue to attempt to establish communication and monitor for signs of distress.
If a vessel has a sail plan that defines expectations for communication during a voyage and expected communications are missed, SAR coordinators consider this as a sign of potential distress even if no other distress signals have been received. Sail plans should be filed with a responsible person or MCTS, who can contact SAR coordinators if expected communication does not occur. If a vessel does not have a sail plan, SAR coordinators will use the vessel’s approximate date of arrival as the time at which the vessel is considered overdue; for extended voyages, this could possibly be days or weeks after an emergency occurs.