The projectiles fired by the 16-inch HARP gun on Barbados belonged to a family of cylindrical, finned missiles called Martlets, named after the martin bird that appeared on the McGill University crest. Inside the barrel of the gun, the Martlet was surrounded by a sabot, a machined wooden casing that protected the projectile as it traveled through the barrel by soaking up the combustive energy and then splitting apart in the air as the Martlet accelerated upward. The Martlets also carried payloads of metallic chaff, chemical smoke, or meteorological balloons to gather atmospheric data as well as telemetry antennas for tracking the missile's flight. Several telemetry systems used in the HARP program were designed by the Harry Diamond Laboratories. The firing of these Martlet missiles was always accompanied by a huge explosion that shook the houses within close proximity, leading to cracks in several areas. Since the Barbados government refused to recognize the damage claims made by householders, HARP fell into ill favor by much of the Barbados population.