are high-powered and hence both very quick and durable purpose-built boats. They are normally painted a highly visible colour such as orange, red or yellow. In terms of design, monohull hullforms are most commonly used, though examples of catamarans, SWATHs and Wave Piercing Hulls also exist. Although some pilot boats are still constructed from steel, the need to travel quickly means lighter weight materials such as aluminium, fibreglass and composites are now commonly used. In some instances, such as the Berkeley Class vessels produced in Australia, a combination of materials is used. Gallery Signalling Pilots identified pilot boats with a large number on the mainsail and by flying a large pilot flag, bisected vertically into two colors, usually white and blue, which added to the boat's visibility. In distress, they would fire rockets and blue-lights at night. A brass signal gun was carried to be used when there was fog and sometimes on fair days. Pilot boats are specially marked to indicate their function. During the day they fly the "H" flag and normally the word PILOT (or PILOTS) is written in clearly visible, large, letters on the sides. At night they have special navigation lights: in addition to the "normal" navigation lights, a pilot boat has a white round light at top and below that a red round light, while a fishing vessel has the red light at top and the white light below. To remember this, some people use the mnemonic "white cap, red nose" to reflect the idea that pilots consumed a lot of alcohol while waiting for ships, thus the white captain's cap with a red nose below it. Pilot boats often also use bright colors, like flashy yellow, to make them clearly visible and distinctive in even the worst conditions. This last mainly applies to the so-called pilot tenders: the vessels that go to the ships to bring the pilot on board of arriving ships or pick them up from departing ships. Depending on the local situation the tenders might be launched directly from a nearby harbour or they are coming from the central (large) pilot station: a pilot boat located at a pre-defined location at sea near a pilotage area. In earlier days nearly all pilots came from a "pilot station" at sea, but with the modern very fast tenders it is often more practical not to have a permanently manned pilot station at