Ãļ§Ö±²¥

Introduction

Recently (Gibaja, et al., 2024), boats dug from single tree trunks found in Lake Bracciano near Rome were classified, on the basis of their morphology, as boats suitable for sea navigation and therefore fundamental for the process of the Neolithisation in the Mediterranean. Such possibilities were considered not only because of the size of boat 1 from this site, but also because of other wooden artefacts found in the surrounding area (Caruso Fermé, et al., 2023).

Description of the experiment

The proposal that the Bracciano boats could have been used for sea navigation was debated since their discovery. The lake could have been connected, via the Arone River, with the Tyrrhenian Sea (Fugazzola and Mauro, 2014). Later, this supposition was accepted as a fact (Mineo, 2015). The complexity of the vessel was supported by the presence of two artefacts with holes and a cut in the shape of "T" (Fugazzola and Mineo, 1995), which could have been used to anchor ropes controlling a sail, to connect two such vessels as a catamaran, or to fasten a stabiliser (Mineo, et al., 2021). The excavation of the Early Neolithic village, where five variously preserved boats were found, revealed wooden paddles made from one piece of wood and an artefact interpreted as a possible steering paddle (Caruso Fermé, et al., 2023). It is important to ask if these artefacts are truly proof of sea navigation. The original Expedition Monoxylon became accepted as an argument supporting the sea faring possibilities of the boat (Mineo, 2015). For the Expedition Monoxylon IV the boat based on Bracciano 1 was made even more accurately to reflect the original. The main aim of the 2023 expedition was to evaluate the sea faring capabilities of the Bracciano 1 boat.

It is important to emphasize that the 2023 nautical experiment best fitted the rules established by John Coles (1979, pp.43-48) the best. The material used(oak) corresponded (rule 1). During the building of the boat, while working on the interior, we dug 3 metres from the total 9 using authentic lithic technology (rule 2). We used modern technology to document the navigation: GPS, the accompanying boats instruments to measure strength and direction of the wind, and a dictaphone to record height and direction of waves, as observed relative to the accompanying boat (rule 3). The work output and performance of the vessel replica were noted (rule 4). We understand the results as only a supporting argument in the discussion on the navigation characteristics of Bracciano 1 (rule 7), though we consider them cardinal. The nautical experiment was carried out with thoroughness and honesty (rule 8). The repeatability of the experiment (rule 5) would be, in this case, very difficult because of the constant change of the weather conditions during the voyage. This, however, relates to Coles' requirement (1979) to not refrain from improvisation (rule 6) but to thoroughly record it.

Boat design

During the Expeditions Monoxylon, the design of the vessel developed as our knowledge did. At the beginning, in 1994, we built a hypothetical boat from a 6.2 m long poplar trunk. Theoretically, it was ready for sea navigation, with a raised bow and stern (See Figure 1). In the same year the Bracciano 1 boat was discovered (Fugazzola and Mineo, 1995). The publication of that find influenced the next boat from 1997/1998, which was built from an oak trunk (See Figure 2a). Because of the size of the available tree, it was only 9.2 m long in comparison to the original's 10.45m. The second boat was adjusted (thinned bottom and walls) in 2018 for the Monoxylon III Expedition (2019) (See Figure 2b). During 2022 we obtained a tree big enough to build a boat which was accurate, in size to Bracciano 1 (See Figures 4 - 13). Because of the close correspondence of its measurements to the original, we considered it as close a replica as we could achieve.

The design of the third boat was still partially hypothetical as the original was not fully preserved. The 11.5 m length of the replica fills in the missing part of the bow and also includes a 0.5m long 'wave breaker' (See Figure 9b) known from ethnographic parallels. Its absence would limit the capability of the boat to navigate in waves. The width of the original was followed, and it allowed for a comfortable seating of two paddlers side by side. The number and position of inner ribs was followed. From the point of view of the navigation, the height of the sides is the most important. The original's sides are preserved to between 44 and 65 cm (Gibaja, et al., 2024). Because of the damage, the sides of the experimental vessel were reconstructed to a height of 75 cm. This had the most influence on the capability of the experimental vessel to navigate waves.

It is important to note that the length of the vessel restricts the influence of high waves. The difference was obvious from comparing the voyage of the first hypothetical vessel (See Figure 1) in high waves in 1995 when the boat lost speed between neighbouring waves, and the third vessel built according to Bracciano 1 where the length allowed it to span two neighbouring waves, so the vessel does not significantly lose speed.

Voyage route

Fig 3. The route of Monoxylon 4 Expedition with marked stages and location of wave types along the route. Map by Ondřej Štulc.

The result of the experimental navigation was fundamentally influenced by weather conditions during the voyage. The more demanding conditions meant more exacting testing of the nautical characteristics of the replica. For example, the route and time of the year suitable for the Monoxylon III voyage in 2019 was chosen deliberately. The main aim was to cover a 100 km long stretch without landing. Therefore, we chose the calmest weather, which in the western part of the Mediterranean occurs mostly in May and June. The Monoxylon IV route was chosen to correspond with historical evidence (Early Neolithic site Çukuriçi Höyük (Horejs, et al., 2015) with finds of large amount of obsidian from Melos - Melos - Franchthi cave with obsidian finds (Perlès, 1990) and evidence of early Neolithisation (Perlès, et al., 2013). At the same time, we chose alternative navigation routes depending on the actual weather, so the navigation along the southern wind later changed to navigation in side waves. The middle part of the voyage could shelter from the wind along the southern coasts of the islands and the longest stage could, in the final phase before arrival on the Greek mainland, use the following wind (See Figure 3). The voyage aimed to land on the islands to sleep and rest during unfavourable weather (strong wind, high waves).

Powering and steering

The vessel was mainly powered by paddling. That corresponds with the finds from Bracciano (Caruso Fermé, et al., 2023). At both sites, two types of paddles were discovered. One is a paddle with a long, narrow leaf, the other with a short and wide leaf. According to modern interpretation, the first one is intended for use in deep water, and therefore, it was chosen for sea navigation. The paddles were made from a single piece of ash wood. These paddles proved effective in waves and allowed for faster frequency of paddling (35 and more strokes per minute) than during earlier expeditions. This affected positively the overall speed, which was more than 5km/hour during the stages powered by paddling only.

We used a sail as a supporting propulsion, We attached it to a sailyard and a mast, operated with ropes (See Figure 4). A 4m long, 10 cm thick artefact, interpreted as a possible mast, was documented near the Bracciano 1 boat find, though the interpretation is tentative (Mineo et al., 2023, pp.38-39). We chose to replicate it based on our earlier experience from the Monoxylon expeditions (Tichý, 2019), which highlighted the possible importance of wind. It represented a return to testing a sail, which had been planned for the first crossing of the Aegean Sea (See Figure 1). At that time, we could not proceed because of our lack of knowledge of weather/ wind conditions. The sail was used minimally in 2019 (Monoxylon III) because of the chosen route and the time of the voyage. That time, we chose a windless part of the year (Tichý, 2020). In 2023, the situation was different. Some of the stages were chosen deliberately to test wind power (See Figure 3) despite the lack of archaeological evidence of sail used in such an early period.

The sail was a simple, loosely woven rectangle, which partially let wind through. That, to a certain extent, mitigated the pressure on the vessel during wind gusts. The sail was usable only for following and following-side winds. Thanks to the experience of the crew, even a very weak wind could be used, with the sail being positioned nearly parallel to the boat. The sail was fastened between two sailyards. It was possible to pull the top sailyard to the top of the mast. The guiding ropes were attached to the ends of the yards. This simple system used five ropes which were attachable to the hull of the vessel thanks to wooden objects with holes, like the 'T artefacts' found near the boats at the Bracciano site. Their replicas were tested in 2019. In 2023, the ropes were attached in a different, simple way. We do not consider the 'T artefacts' necessary for fastening ropes. Their function cannot be either confirmed or denied by the experiment. The sail could have been very quickly lowered by lowering the top sailyard and simultaneously rolling the sail onto the bottom sailyard. The rolled sail was then fastened vertically to the mast.

As a result of our trials, we can say that a simple sail could successfully support a vessel in the conditions around the islands of the Aegean Sea (See Figure 3). It was most noticeable during stages two and three, but also in the second half of stage 15 (See Figure 13a). The use of the sail speeded the vessel up and shortened the time spent at sea, even if used only for parts of the stages. This way, it reduced the influence of a quick weather change on a safe landing. Support of the sail managed to increase the speed of the vessel up to 7 km/hour. The average speed of all stretches thus reached 5.4 km/hour, that is over 1km faster than in 2019, when the sea conditions were much calmer, and we alternated two crews.

The fundamental tool for navigating the replica vessel was a long steering paddle (See Figure 5, 11b). In high following waves (up to 1.5m) the steering paddle sometimes did not reach below the sea surface and the vessel became uncontrollable. Because of the total weight of the vessel (2.7 tonnes when dry, at sea up to 3.3 tonnes) attempts to control the boat with just paddles were not effective. It is, therefore, a question if artefact 12005 found between boats 2 and 4 at Bracciano (Caruso Fermé, et al., 2023) could have been used as a helm or if it is just an alternative fastening of the paddle leaf. Equally, it could have possibly served to steer while navigating the lake.

Crew

The modern experimenter is the weak link in any archaeological experiment. They are part of a modern society, and their experiences and skills influence the experiment (Dvořáková, 2024). On the top, we do not know anything about physical performance in prehistory. While we justifiably presume that it was better than of a modern human, it does not apply on a general level. I would like to correct the information that the crew of Monoxylon III (2019) was inexperienced (Mineo, et al., 2021; Mineo, et al., 2023; Gibaja, et al., 2024). That information came from unofficial internet sources. In reality, part of each crew were members of the previous expeditions. Even among the 21-member crew of 2023 there were five people who took part in all four expeditions and another eight took part in one or two of the previous expeditions. It was important that experience and physical condition were not the only measures we could arrange to ensure the quality of a nautical experiment.

There are other factors concerning the crew. For example, in 1995, a third of the crew switched while at sea. In 1998, during the longest expedition (800km), three crews switched. In 2019, two crews switched. In 2023, there was only one crew.

The positions of those who manipulate the sail are important as these are specialised activities. There were two helmspersons who shared the effort because of the great strain of sailing in waves. In 2023, the number of crew members rose to 21 (until then, at most 11 persons), which required one crew. A failure of a paddler is when, because of tiredness, they decrease the frequency of paddling, given by seat one, or they stop paddling and lower the vessel's performance. One of the risks we faced in 2023 was the hot weather, with temperatures approaching 40°C. When the surface was calm, the crew needed to bathe (See Figure 5). Even this time was used for taking measurements (possible influence of the surface currents), but i