The Caesarea Development Corporation, with the assistance of researchers from the Haifa University, is launching a unique underwater archeological park.
The underwater park will reveal to both amateur and professional divers construction techniques used by Herod to build the ancient port, attempts made to restore the port, following its gradual sinking, and the remnants of wrecked ships and sunken cargo.
The park includes four diving complexes with 25 stops reflecting the wonders of Roman naval engineering and the vicissitudes of the harbor during its 2000 years of existence.
The first complex is intended for amateur divers who will be able to tour it with snorkeling equipment. The other 3 complexes require the use of professional diving equipment, oxygen tanks, etc.
The sunken harbor covers an area of 200,000 sq. m. and includes remnants of basins, breakwaters, loading piers, storage rooms, a promenade, and a lighthouse. Wrecked ships and cargos, ancient anchors, and even one ship that carried illegal immigrants, have been discovered on the seabed.
The Caesarea Development Corporation believes that the park will attract divers and archeologists from around the world, as the underwater tour affords a unique, one of its kind experience – following the technical wonders of ancient harbor construction, observing the ingenious building methods of Herod’s engineers, who built the first breakwater in history.
The underwater park was adapted for visitors with funds provided by the Caesarea Development Corporation, however a significant part of future rehabilitation and maintenance will be performed by volunteer divers.

About the harbor:
Herod began building Sebastus, the harbor of Caesarea Maritima, even before he established the city, with the intention of forming a major port within the domain of his kingdom for the valuable goods that would pass from the Indian Ocean to the Mediterranean Sea.
The demand for these goods (spices, textiles, and jewels) had greatly increased throughout the Roman Empire since the reign of Caesar Augustus. Within the matter of a decade Herod succeeded in building the harbor and the city, which quickly became the economic and political center of Palestine.
Caesarea and its harbor endured many vicissitudes throughout history, but while Caesarea was always well known, its harbor disappeared and was forgotten.
The site was initially recognized by a marine expedition in 1960. Most of the underwater excavations were held since 1975 by the Center for Maritime Studies of the Haifa University, headed by Prof. Avner Raban, until his untimely death in 2004.
Prof. Raban initiated establishment of the underwater park in 1992, and this initiative is now being renewed, 13 years later. This document is based on his numerous publications and dedicated to his memory.
Jewish historian Flavius Josephus in the late first century AD described the harbor as he had seen it, but he was not very precise in his descriptions of the methods of construction and the nature of the parts located underwater. Research indicates that the construction of the harbor better reflects the description of Vitruvius, the Roman engineer who was Herod’s contemporary. This is the most ancient harbor discovered that used Vitruvius’s engineering recommendations, and as such it may be seen as the first artificial harbor in history, the largest and most modern in the Roman Empire of its time.

General description of the harbor and its components:
(The numbers and letters in parentheses are the underwater markings used during recent work.)
The protected anchorage area covered approximately 200,000 sq. meters. It included three sub-basins, of which the innermost was based on an excavated basin, which is today almost entirely on land. Of this basin a circular tower, part of the Hellenistic fortification of Straton’s Tower, the precursor of Caesarea, has remained in the water. The tower is on the northern side of the entrance to the inner harbor. It is 13 meters in diameter and it is built of hewn stones arranged in an outer circle. Its narrow side faces outward (“header blocks”). In the eastern side of the tower there is a depression among the hewn stones from which the tip of a lead pipe protrudes. Fresh water flows from the pipe – indicating the high elevation of the water table in this area (A/1). Today the inner harbor is mostly buried under the buildings on the beach and under the lawns. On the eastern (land) side, at the foot of the temple platform, it is possible to see a quay with a mooring stone, and below it a pool which was fed by ground water. Research has indicated that the inner harbor became blocked in a process that began upon its establishment, and extensive attempts were made to preserve it as a harbor. However, recurring flooding obstructed land construction. Only in the Ancient Islamic Period was an organized and sophisticated residential quarter built in this area. This quarter is today mainly located under the lawn surface that now covers it.
The middle basin was based on a natural bay and it is parallel to the modern wharf. Under the modern cement pier it is possible to see the original Herodian paving of the great breakwater (A/6). Additional piers protruded as “finger” quays into the harbor basins and thus increased the anchoring space (B/8, C/13, C/16).
The outer, largest basin was formed artificially by two giant breakwaters, the first engineering project of its kind. The length of the first breakwater is approximately 500 meters, its base is in the south-east and it faces north-west in a wide arc. Its original width at its base was approximately 60-70 meters (B/12). A seawall with towers at regular intervals (C/16, C/18, C/19, D/25) was situated on the outer part of the breakwater, while a loading pier was installed on its inner side (B/8, C/15, C/19), including storerooms (C/17) and a promenade along its full length. The largest tower was situated at the northern end of the breakwater. This tower, the Drusion, served as the port lighthouse (D/21). The width of the entrance channel was approximately 20 meters (D/22-23). Outside the port entrance there were two towers signaling the entrance course (D/20). The Drusion Tower and the Western Tower were connected in their upper part by a surface intended for statues (which have not survived). The anchorage was bordered in the north by a shorter straight breakwater, which served as the base for the port administration building (D/24). Here special niches were found in the stones, perhaps intended for pulleys holding an iron chain with which the entrance could be closed when necessary.

Construction methods and special characteristics:
Herod’s engineers surprised even modern port planners by some of the special characteristics discovered in the ancient harbor. One of the problems encountered by ports in all times is that of seasonal damages to the main breakwater and the splashing of the waves that interferes with unloading and loading during storms. These problems were solved in the Herodian harbor by a subsidiary breakwater, which was quite narrow (a width of approximately 6 meters) and only reached to the sea level. It was built parallel to the main breakwater and outside it, prevented the breaking surge and was easier to repair seasonally than the main breakwater (B/11). This subsidiary breakwater was called prokomatia in Greek and it is mentioned in Josephus Flavius’s descriptions of the harbor construction.
Another problem is the blocking of the harbor by silt, necessitating constant digging and dredging, performed today by mechanical tools. Herod’s engineers found a solution to this problem as well. In the southeastern margins of the middle basin there is a channel carved in the rock with a threshold higher than the seabed, reaching a level of 20-30 cm. above sea level. In the rock sides it is possible to discern vertical grooves for insertion of sluice gates, set here in order to regulate the flow of water within the channel. From plans designed in the 19th century it seems that there were additional channels of this type to the east of the channel described (in the area of the Crusader moat channel). Their function was to bring silt-free water into the harbor and to flush the additional water constantly outwards. This flow ensured the removal of deposits from the bed of the harbor and prevented the entering of sand and silt through the harbor mouth. Proof of this is found in a layer of 1 meter and higher at the entrance of the harbor (D/22-23) which included muddy silt and an abundance of pottery, metal tools, ship parts, and other deposits that were carried here from the floor of the harbor when it was still active.
The underwater tour reveals some of the sophisticated building techniques that were used in construction of the harbor and that surprised the researchers. Most of the harbor foundations were built from concrete – a Roman invention that was forgotten when the empire fell and redeveloped in modern times. The concrete was poured in various-sized wooden caissons (14X7 m., 13X16 m.), built on the beach from choice imported wood using choice woodworking methods. Remnants of the frame wood have been preserved in various places (D/21, D/25), and in others it is possible to discern impressions that serve as a negative of those frames (C/17). The mortar was a special mix, consisting of lime and a significant quantity of imported volcanic ash (pozzolana), which adapted the material for use in the sea. After pouring a little cement into the caisson on the beach, it was then towed to its appointed place, moored to the bed with chains, and then more cement was poured from service boats, until the frame sunk to the bottom. There the caisson was stabilized and the pouring was completed until the desirable height. The caissons were placed next to each other and served as a type of artificial island, a foundation for the breakwaters. “Caves” or “tunnels” discovered in the base of the port lighthouse structure (D/21) were found to be serious erosion of the mortar from the second pouring stage, which was the most problematic.
Ancient engineers saved money and materials by using double-walled caissons, the hollow walls of which were filled with mortar, leaving the middle empty. The inner space of the frames was filled over time by sand brought by the waves (C/19, D/25).
The platforms and the upper structures were built from giant ashlars, some of which reached a length of seven meters and a weight of ten tons and more. Sometimes these gigantic stone blocks were attached with iron clamps reinforced by lead sockets (D/24).

The sinking of the harbor and its later stages:
Unfortunately, the harbor was built on two geological faults, located about 150 and 450 meters from the current shoreline. The sinking apparently began immediately after construction, and it has been continuing until today. It grew worse due to a series of earthquakes. Today the submersion has reached 5-7 m, however already in the fourth century AD the top of the breakwater was under water, as evidenced by the ships wrecked on it. These shipwrecks and other remnants date the stages of the sinking and the attempts to repair the harbor, mainly in the Byzantine Period.
The best indication of the harbor’s submersion are the installations that were originally located on the shoreline, in order to fulfill their function, but which at present have sunk deep under water. These are primarily the piers (B/8, C/15) as well as a mooring stone (C/16), all currently 5-7 meters underwater. The harbor entranceway was also found to have been blocked in the Byzantine Period, in the early sixth century AD, when efforts were being made to rehabilitate and renovate the sunken harbor. A massive amount of fill was poured on the breakwater and the entranceway, as far as the lighthouse (D/23).
In addition to sunken harbor installations, the tour will present various findings from ships wrecked in the area of the harbor while trying to enter it over the sunken remnants of the breakwaters, which became dangerous reefs. Near the entrance to the harbor is the wreck of a large ship, whose lower part was covered by lead boards. The manner in which the boards were torn shows that it crashed into an underwater obstacle and drowned. Its cargo included a number of lead ingots, inscribed with the name of Caesar Domitianus “Germanicus” (late first century AD) and also the name of the mines from which they came (in the Balkan region). The findings from this shop are no longer in the field, but in another place in the harbor we can see the cargo of a different ship, a large merchant ship from the Roman Period that sunk to the bottom with its expensive cargo – blocks of raw marble. The marble served for creating carved architectural items, coffins (one of which is made of lead) and other prestigious uses in Caesarea (B/9). The only remnants of another ship, dated at the third century AD, are a pile of jug pieces (amphorae, C/18). An additional ship, dated in the late Roman Period (fourth century AD), left its basalt ballast stones on the sea floor. These were carved in the shape of a double and concave trapeze in order to fit in their place in the ship’s interior (C/14).
In the Middle Ages the ancient harbor was no longer in use. Caesarea’s Muslim rulers, and later the Crusader conquerors, recycled marble and granite columns taken from the ruins of Roman Caesarea and in the area of the Middle Basin they erected a sea wall (A/2), a square tower (A/3) and a pier (A/4), but the maritime activity never resumed its days of glory. The wall and the towers were built in poor quality from a pile of rubble and lots of cement. Since the Byzantine Period the bay to the south of the Crusader fort was apparently used as a partially-protected anchorage.
The modern wharf was built after the establishment of the State of Israel, in order to serve the fishermen of nearby Kibbutz Sdot Yam. The metal body of an old ship that carried illegal immigrants (A/5, B/7) was filled with cement and sunk in the northern tip of the breakwater. Thus it too was built of cement, and here too an “artificial island” was used to form the foundations, but in contrast to the Roman construction, this breakwater is in a state of advanced deterioration fifty years after it was built…

Ancient anchors:
The underwater tour will also include a grouping of six ancient anchors, demonstrating the development of the anchor from the beginning of history until modern times. A similar grouping of anchors is situated in the land courtyard at the southern tip of the inner harbor, outside of the walls. The anchors have been placed in the sea bed as they originally functioned.
1. Weight anchor – A stone anchor with one hole, used in the third and second millennium BC (Bronze Period). In order to improve its efficiency, it was usually complemented by another anchor attached along the same rope, the two anchors kept further apart than the water depth.
2. “Byblos” anchor – named after the city Byblos in Lebanon, center of ancient Phoenician shipping. Wooden stakes were inserted in two of the holes and the anchor is flat, so that it would land on its side and the stakes would attach themselves to the seabed. It dates from approximately three thousand years ago.
3. Composite anchor – made of wood and lead, shaped similar to the admiral’s anchor. The shaft and the arms are made of wood and it has a leaden core. A lead stock is attached to the upper side, ensuring that the arms adhere to the seabed. Another part made of lead lends heaviness and maintains the angle between the shaft and the arms. The arms are covered with copper to prevent erosion. This anchor is dated from approximately two thousand years ago, from the Hashmonean Period.
4. Roman anchor – Cast of metal and similar to the previous anchor in its shape and function.
5. Cat anchor – also cast of metal, with four hooked arms and a long heavy shaft. There is no need for an upper stock in this anchor. This anchor is characteristic of the Middle Ages, Arab and Crusader (Italian) shipping, and is still used in small boats. It also served as a hook for grasping enemy ships in times of naval warfare.
6. Admiral’s anchor – a round stock and wide teeth, used since the beginning of the new shipping era in the 14th century AD. It does not feature many improvements over the Roman Period.
From here we shall turn south and cross the Herodian breakwater horizontally, a distance of approximately 70 meters on a sandy bed.