the B gun: six if the spray and blast shield was fitted, three if not. A 40 mm QF 2-pounder Mk VIII "pom-pom" was fitted as bowchaser to ships that were to serve as Coastal Forces control frigates. The bridge layout was significantly altered; the biggest alteration was the addition of a two-tier director control tower that improved visibility and gave better protection to the equipment. Vertically fired "snowflake" parachute flare projectors were fitted to the bridge wings. Anti-submarine More depth charges were fitted on the upper deck of each side of the ship, allowing for about 200 in total; Royal Navy smoke floats were fitted above the depth charges in addition to the US Navy chemical smoke cylinders fitted to the stern of the Captains. A medium frequency direction finding antenna (MF/DF) was fitted in front of the bridge and a high-frequency direction finding (HF/DF, "Huffduff") Type FH 4 antenna was fitted on top of the mainmast; furthermore, a radio-receiving set tuned to the frequencies used for ship-to-ship communication by German U-boats and E-boats was fitted and a German-speaking rating carried. The Captains were eventually given Type 144 series Asdic (sonar) sets, an upgrade from the original Type 128D, and a Foxer was fitted to the aft of the Captains (and most other Atlantic escort vessels) during 1944 to counter the new G7es acoustic torpedoes. Navigation and communications The steel parts around the binnacle (the enclosure containing the compass) were replaced by non-ferrous materials. In addition to the standard US Navy long-range position-fixing set (LORAN), a Royal Navy GEE short-range position-fixing set was fitted. A radar interrogation system was installed that was able to challenge ships at sea (only ships likewise fitted with the system would be able to reply), along with four coloured fighting lights (signalling lamps installed on the yardarm to aid recognition by friendly forces during night fighting). Camouflage and insignia Following standard Royal Navy protocols, all of the Captains had large pennant numbers painted on the sides and stern of the hull, usually in blue, red or black. The escort groups to which most Captains were assigned had their own individual insignia; these distinctive and colourful designs were painted on the side of the ship's funnel, and if the ship was home to the escort group's senior officer it would also have a coloured band painted around the top of the funnel (usually in blue