Tides and tidal ranges
General
Seiches, which are dramatic changes in tidal level experienced in relatively enclosed areas of water and caused by very low barometric pressure, sometimes occur in the Adriatic. The surge created by a seiche can be particularly dangerous to a yacht in harbour or in an anchorage. The Admiralty Pilot gives an example of a seiche, which occurred at Starigrad (on Otok Hvar, 43°1 l'N l6°35'E) on 19 September 1977. A deep low pressure trough moved SE across the area from the northern Adriatic. Not long after the passage of the front, the water level in the harbour dropped by 1 .8m, only to rise again by 2.7m a few minutes later. These oscillations continued for several hours, with each cycle lasting about ten minutes. The Admiralty Pilot does not record what damage was caused on that occasion, but no doubt yachts and other vessels in the harbour would have been very lucky to escape damage, if not total destruction.
Currents
There are three types of current encountered in the Adriatic: tidal streams, regular inshore currents, and wind-driven surface drift currents. See the diagram (on page 4) showing the surface current tracks in the Adriatic. Tidal streams are weak in the southern Adriatic and can flow at up to half a knot in the norther Adriatic. Near the Croatian coast the combination of the regular inshore current and the tidal streams creates a strong northwest-going current on the flood tide and a weak southeast-going current on the ebb tide. The southeast-going circulating current on the Italian coast is not much affected by tidal influence. Wind direction however does influence this circulating current. Regular inshore surface currents basically flow in an anticlockwise direction around the Adriatic. The currents are variable, but typically north-going at a rate of up to half a knot off the coasts of Albania and Montenegro and southern Croatia. From there, they flow in a NW direction off the Croatian coast and are felt up to 20M offshore. They then flo around the Golfo di Venezia, and then curve round to flow in a SE direction off the eastern Italian coast. These currents are stronger off the Italian coast where they can flow at up to 3kns in the S, but their influence is not felt so far offshore. In the N, the currents are felt up to lOM offshore, and in the Sup to 6M offshore. The strength of these currents is irregular. In the summer there is little current off the Italian coast north of Fiume Tronto (43°55'N 13°05'E). Further south the strength of the current increases until it can be running at up to 3kns off the south Italian coast. These regular surface circulating currents are modified by tidal streams and wind-driven surface drift currents. Surface drift currents A wind blowing from a constant direction causes water, by surface friction, to flow in the same direction as the wind. This is known as a surface drift current. These surface drift currents can mask, and even reverse, the circulating currents mentioned above. Currents at the entrance to the Adriatic vary in direction. Off Albania, the currents flow northwards. Off Capo Santa Maria di Leuca, the current is southeast-going and usually strong. Even in calm weather, the current can be flowing at 2kns inshore, and at lkn 6M offshore. NW winds can increase the current to 3kns. There is also a current which flows from Italy towards Albania. The currents are described in greater detail in the individual pilotage sections. The Adriatic Sea is crystal clear in most areas, and sea temperatures can be as high as 31 °C, even out in the deep channels! Pollution Pollution is a matter of concern throughout the Mediterranean, and the Adriatic is no exception. The most polluted areas of the Adriatic are near the large industrial centres where chemical effluent is discharged, near the Po delta, and in the area around Venice and Trieste. The Po delta drains agricultural areas of Italy and carries large quantities of dissolved fertilizers into the Adriatic. This encourages the growth of plankton in the northern Adritic, which stains the sea a dark bottle green. The stamed water is noticeable from the lstrian Peninsula northwards, and on the Italian side of the Adriatic is obvious almost as far south as Ancona. Many towns and cities, especially in the former Yugoslavia, used to discharge untreated sewage into the sea via the harbours, making these harbours particularly unpleasant. The most polluted arbour we visited was Split. On our most recent v1s1t, the harbours were cleaner, although Pula was still a dirty harbour. There are regulations governing the discharge of waste, including oily waste, from vessels. Oily waste should be kept in a special container for subsequent safe disposal, and yachts should not pump bilges or toilets in harbour. These regulations however do not seem to be enforced, and the worst offenders are the local fishing boats. Yachts should, as a matter of courtesy, avoid pumping bilges and toilets in anchorages used ?Y swimmers. Some Slovenian marinas have fac1ht1es for pumping out toilet holding tanks, but to date these facilities are not available in Croatian mannas. Buoyage and navigation aids The Adriatic Sea is for the most part well provided with buoys and other aids to navigation. The exception is the coast of Albania, where, as far as the passage-making yacht is concere?, many of the lights will not normally be visible <_mts1de of Albanian territorial waters. The Admiralty also warns that navigation aids in Albanian waters are not always reliable. IALA Buoyage System A applies throughout the Adriatic. All harbour entrances in Montenegro, Croatia, Slovenia and Italy, where lit, are marked in the conventional manner, i.e. red lights on walls and dangers which are to be left to port on entry, and green lights on those walls and dangers to be left to starboard on entry.
Coast Radio Stations
The Adriatic is served by a number of coast radio stations with just a few gaps in coverage. Albania, Montenegro, Croatia and Italy all operate them. The services offered include public correspondence, medical advice, and the issuing of weather forecasts and other navigational information. Besides the national language, English is used. During the summer months the Croatian and Italian coast radio stations also give the forecasts in German and Italian. The coast radio stations open for public correspondence in the Adriatic are: Greece Kerkira (Corfu). Call Olympia Radio Albania Sarande, Vlore, Durres, Shengjin Serbia and Montenegro Bar Croatia Dubrovnik, Split, Rijeka Italy Trieste, Ancona, San Benedetto del Tronto, Bari Many of the ports and marinas can be contacted on VHF radio. The national radios also offer services of interest to the yachtsman. Working frequencies, channels, and times of forecasts are given in the introduction to each country. Coastguard and lifesaving There is no voluntary organisation in the Adriatic comparable with the Royal National Lifebat Institution in Britain. In Montenegro, Croatia, Slovenia and Italy rescue at sea is organised and coordinated by the harbourmasters. In Italy the capitaneria di porto, a quasi-naval organisation with representatives in even the smallest harbours, organises search and rescue operations, calling upon the aid of fishing boats and other vessels in the area as necessary. At many of the larger ports the capitaneria di porto has fast launches equipped as lifeboats. There are no dedicated lifeboats to be seen in Croatia, Montenegro or Slovenia. In Croatia the main maritime rescue co-ordination centre is based at the harbourmaster's office in Rijeka, with subcentres in Dubrovnik, Ploce, Split, Sibenik, Zadar and Pula. They are able to call upon search and rescue vessels if required. In Croatia, assistance can be requested on VHF channels 16 and 10, or DSC channel 70. Commercial shipping and fishing The Adriatic Sea is busy with commercial shipping and fishing boats. Yachts should therefore keep a good watch at all times, and at night should show na viga ti on lights. Vessels encountered range in size from small coasters, which call at many of the smaller ports, to large ocean-going tankers and ships. There re also busy ferry lines linking many of the Adriatic ports with each other and with Greece. Naval vessels may also be encountered exercising in the Adriatic, particularly off Boka Kotorska, in the approaches t? Venice north of the Po delta, off Porto Corsm1, Ancona and Brindisi. At night, unlit high speed motor launches may be encountered. These may be Italian guardia di finanza (customs) launches on patrol looking for smugglers, or they may be smugglers. Compared with other parts of the Mediterranean, the Adriatic is a rich fishing area, although the catches still do not compare with the catches landed at North Sea ports. Commercial fishing is an important economic activity and fishing fleets operate out of all the states bordering th AdnatJC. The Italian fleet is the largest with f1shmg vessels based at most harbours. The Croatian fleet is smaller and mainly works from northern and central Hrid Sveti Ivan na Pucini lighthouse off the W coast of lstria, near Rovinj. The Adriatic coast is well supplied with modern navigation aids Croatia. Several of the ports in these areas have fish canneries. It is rare to see a fishing vessel in Montenegrin waters. Fishing methods There are various fishing methods practised in the Adriatic. The majority of the larger fishing vessels are trawlers. Sometimes the trawlers work alone, sometimes in fleets. In Italian waters from Monfalcone to Bari it is not uncommon to see shellfishing boats in comparatively shallow water a few miles off the coast. From a distance, these are strange looking vessels with a large metal cage carried on their bow. Their method of fishing is to drop a buoyed anchor from the stern, motor forward a hundred yards or so, drop the cage from the bow onto the seabed, and then pull themselves back to the anchor, dragging the cage along the seabed as they go. The cage is raised from the water, the contents rinsed, and then poured onto a metal sorting tray, before the whole process is repeated. When sailing near these fishing boats never pass too close to them. They may take off at speed, without any warning, dragging their anchor cable across your bow. At the head of the Adriatic, there are several areas where shellfish are farmed. The shellfish beds, which consist of rows of oil drums or floats with ropes hanging between them, could be a hazard to yachts on passage. Their position is indicated in the appropriate sections. There are a number of areas in Croatia where there are oyster beds or other shellfish farms, but these are rarely a problem for the passage-making yacht. Fish farming is, however, increasing. The location of the farms, where known, is given in the appropriate sections. Nets, lobster pots, and long lines, all marked by buoys, are also found in the Adriatic. In Italian waters, the buoys and floats are usually easily visible. Most have flags on them, and, if left out at night, are lit by small flickering lamps. In Croatia and Montenegro, on the other hand, something which from a distance appears to be a bit of flotsam (a piece of polystyrene or an old plastic detergent bottle) may prove to be a fishing float with a line or net attached to it. Some of these polystyrene floats may only be 2 inches square! Be particularly careful when entering an anchorage, especially at twilight. May, June, and sometimes July are the months when long nets are set out at right angles to the coast to catch the migrating tuna and swordfish. The former system of death chambers is now illegal in Italy. Tuna fishing is carried out along the foot of Italy in the approaches to the Adriatic, and into the southern part of the Adriatic. The nets are usually set at night in good weather and can stretch over 7M out to sea into the shipping lanes. The nets lie close to the surface, and although their ends are lit by small flickering lights, they are frequently damaged by ships, and are a real hazard to yachts sailing at night. We have met several yachts on our travels, which have become entangled in the nets and have had to be cut free by the fishermen and towed into harbour. In some parts of the Adriatic small fishing boats go out at night equipped with bright gas lamps. These lights can be confusing. As the boat bobs up and down in the swell, the light can seem to assume the characteristics of that lighthouse you are looking for! With the exception of the tuna boats and the small 'sardine' boats mentioned above, most fishing vessels in the Adriatic only work during the day. The fishing boats leave harbour early, often before 0500 and return in the afternoon from 1530 onwards. They rarely leave harbour on Sundays or public holidays. If there are no suitable spaces in harbour for a yacht, it may be possible to tie alongside a fishing boat overnight. Always check that this will be alright with the fishermen, and be prepared to get up early to move. Many fishing boats in Italy have guard dogs living on board, so before leaping on a fishing boat to take your lines ashore check the reception committee! Oil exploration
Adriatic Navigation Guide Images for Tides and tidal ranges
Adriatic Navigation Guide images and captions provide additional visual reference for this navigation location.
