Bulletin No.: 11/1995

Date (Y-M-D): 1995-06-01

Subject: Radar Reflectors on Small Vessels: Construction, Fitting, and Limitations

This Bulletin replaces Bulletin No. 04/1992 and has been replaced by Bulletin No. 14/1998.

This updated Bulletin replaces earlier Bulletins 3/81 and 4/92, in order to remind owners and operators of small vessels of the importance of complying with the requirements for using radar reflectors.


In the past few years, several small vessels operating in restricted visibility or heavy weather have been run down or swamped by larger vessels due to lack of detection. Subsequent investigations have revealed that many of these vessels were not using a radar reflector to increase their chances of being detected.

Small vessels generally make poor radar targets because they are mainly constructed of non-metallic materials and because they present a low profile due to their small amount of superstructure. Even in good visibility, they are difficult to see from the bridge of a large vessel since they are so low down on the horizon that they do not show against the sky. In rough weather, they are often screened by spray or may not be seen when in the trough of a swell. At night, their navigation lights may be obscured by the presence of shore lights in the background. In restricted visibility, where radar and the exchange of sound signals are the only means of detection, it is important that small vessels use radar reflectors to indicate their presence to other vessels in the vicinity. This is particularly important for small fishing vessels, which operate in all weathers and in a manner which may make it difficult for larger vessels to determine what action they may have to take to avoid collision.

Collision Regulations

Rule 40 of the Collision Regulations, TP 10739, requires a small vessel that is less than 20 metres in length, or is primarily constructed of non-metallic materials, to carry a passive radar reflector that meets the required standards. Flexibility, however, was intentionally built into the provisions of these regulations to permit exceptions from compliance, provided it is impracticable or not essential for the safety of the vessel to carry a radar reflector.

The vessel owner/operator makes the initial decision as to whether the carriage of a radar reflector is practical or essential for the safety of the vessel. If in doubt, the local Coast Guard, Ship Safety office should be contacted for advice. Although it may not appear to the owner/operator that there is an obvious need for the carriage of this equipment, a marine surveyor may indicate that a radar reflector is essential for the safety of the vessel and its occupants, based on incidents where small vessels have escaped detection.

The interpretation of "impracticable" or "not essential" for the safety of the vessel is probably best illustrated by the following examples, and may assist small vessel owners/operators in reaching a decision concerning the carriage of a radar reflector.

Small vessels which operate offshore in all types of weather or which operate in busy waters in darkness and/or restricted visibility should permanently display a radar reflector for their own safety. For example, small vessels should display radar reflectors when fishing in offshore areas such as La Pérouse Bank, the Grand Banks and on other traditional fishing grounds. In addition, small vessels should display radar reflectors when in busy waters such as the Gulf and St. Lawrence River, the Great Lakes, Georgia Strait, Juan de Fuca Strait and when operating in fairways, channels or in entrances to harbours.

On the other hand, it would be impracticable and not essential for the safety of small vessels, runabouts, canoes, etc., to carry a radar reflector when used at the cottage or at resort areas for short trips along the lake or for fishing and water-skiing purposes. Such vessels usually operate close to shore and are normally too small to carry a radar reflector. Furthermore, they generally operate in good weather and often in areas where a radar reflector may be of little use.


Many fishermen consider that equipment such as trolling poles, and/or various makeshift gadgets such as washing machine impellers, can be used in place of a radar reflector. These devices do not substitute for a good radar reflector that has been designed, constructed and properly positioned to ensure maximum reflective performance under all conditions likely to be experienced in the marine environment. Efficient reflectors are relatively inexpensive and represent a modest investment when compared with the cost of a vessel, its equipment and the lives of those on board.

Small vessel owners/operators wishing to build a radar reflector that meets the required standards can obtain plans from their regional Ship Safety office. Mariners are cautioned not to deviate from these plans, as the design and fitting of these reflectors have been tested to give the maximum echoing area.

Detection Limitations

Operators of small vessels should be aware, however, that during heavy weather, even when fitted with a proper radar reflector, small vessels may not always be visible on the radar of an approaching vessel. Despite the use of a radar reflector, detection can become intermittent when the reflector disappears in the trough of a swell or large waves. For this reason, it should be borne in mind that there is no substitute for keeping a proper look-out and maintaining an efficient radar watch.

This Bulletin replaces Bulletins 3/81 and 4/92.

Keywords:                                  Questions concerning this bulletin should be addressed to:

1. Radar reflectors
2. Detection
3. Construction
D.G. Jenkins
Transport Canada
Marine Safety
Tower C, Place de Ville
11th Floor, 330 Sparks Street
Ottawa, Ontario K1A 0N8

To add or change your address, contact us at: marinesafety@tc.gc.ca

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