AccueilNuméros21PostersThe size of wooden components in ...

Posters

# The size of wooden components in relation to the tonnage of Greek and Roman ships

Emmanuel Nantet
p. 365-368

## Résumés

Cet article traite de l’influence du tonnage sur la taille des éléments architecturaux en bois d’un navire. Il repose sur une liste de 66 tonnages, élaborée au moyen d’une méthode employant trois procédés pour déterminer le tonnage (restitution graphique des lignes de coque, formule de jauge et poids de la cargaison). Cette liste note l’épaisseur du bordé et la hauteur des membrures. Cependant, l’article évoque également d’autres facteurs tels que l’évolution des types architecturaux.

Haut de page

## Entrées d’index

### Mots-clés :

Membrure, restitution graphique de la ligne de coque, bordé, tonnage

### Keywords:

Frame, hull line reconstruction, planking, tonnage
Haut de page

# 1. What is tonnage?

1Tonnage is the load capacity of a ship – the space that can be used in a boat for merchandise (Nantet 2016). It should not be confused with displacement, which is the overall amount of water moved by the ship while she is sailing. Tonnage gives a valuable clue to estimate the volume of trade. It helps us to understand the scale of trade in which the ship was involved. While ancient mariners used volume units of measurement, historians prefer to provide tonnages with weight units of measurement in order to allow a more relevant comparison to the size of the ships.

# 2. How to estimate tonnage?

2The tonnage of a ship can be estimated via three methods (Pomey, Rieth 2005, p. 41-45). The first provides the most accurate results and relies on a close study of the hull remains. Indeed, if a significant part of the hull is preserved, it is possible to reconstruct the original hull lines of the ship and thus the loaded displacement and the deadweight tonnage.

3However, this method cannot be carried out in many situations, since the hull remains are not always sufficiently well preserved to allow a reliable reconstruction of the hull lines. In this case, only the overall dimensions of the ship can be estimated. It is possible then to use a formula, similar to those formulas used in the early modern period, to provide a quick estimate of the tonnage of a ship. When used by archaeologists, the ‘tonnage formula’ provides a result that must be considered as more approximate than the result obtained through the first of our three methods.

4Nevertheless, it may be that the hull is not well preserved, which means that the overall dimensions cannot be estimated. It is still possible to add the weight of each item of merchandise found in the shipwreck in order to estimate the weight of the cargo when the ship sunk. Of course, the relevance of this estimate relies heavily on the accuracy of the available data recorded in the field, which can be impacted by many factors, such as looting by unscrupulous divers. In other words, the weight of the cargo, as estimated by archaeologists, can sometimes be very different from the tonnage, if, for example, the ship was loaded with a cargo of organic material, such as grain or fabric, which has not been preserved after 2000 years in the sea.

5Therefore, a comparison between the results generated by these several methods is possible. However, it must be carried out with great caution. With caution in mind, this methodology has been applied to 102 shipwrecks (Nantet 2016), and two further, recently published examples, i.e. 104 Mediterranean shipwrecks, dated from the Archaic period to the Muslim conquests in the Mediterranean in the 7th century. For this study, only seagoing ships have been considered, while riverboats have been excluded.

# 3. The tonnage, a major impact on the size of wooden elements

6The database also allowed comparisons to be made between the tonnage of the ships and the size of their wooden elements, such as the thickness of the planking and the moulded side of the frames. Of course, such details about the components of the hull are not always available, since hull remains might not have been preserved or publications do not include details about the specific locations where measurements were taken. Thus, only 66 hull remains out of the 104 shipwrecks were sufficiently well documented, although very briefly in most cases (table 1).

Table 1: Estimates of the tonnage of ships from their remains and comparison with their wooden components

 Name Date Deadweight tonnage (tonnes) Methodology Average planking thickness (mm) Average moulded frame (mm) References Mazarrón 1 – 650/– 600 4 Tonnage formula 36 70-80 Nantet 2016: no 3 Mazarrón 2 – 650/– 600 2-2.8 Weight of the cargo unknown 40 Nantet 2016: no 4 Pabuç Burnu – 600/– 550 16 Tonnage formula 32-45 unknown Nantet 2016: no 6 Bon-Porté 1 – 540/– 510 2 Tonnage formula unknown 110-140 Nantet 2016: no 7 Cala Sant Vicenç – 530/– 500 30 Tonnage formula 45-50 310 Nantet 2016: no 9 Jules-Verne 9 – 510/– 500 2 Reconstruction of the hull lines 29 100 Nantet 2016: no 10 Jules-Verne 7 – 525/– 500 12.2 Reconstruction of the hull lines 25-30 – Nantet 2016: no 11 Golo – 510/– 490 4.5 Tonnage formula 33 unknown Nantet 2016: no 12 Grand Ribaud F – 510/– 490 40 Weight of the cargo unknown 260 Nantet 2016: no 13 Gela 1 – 500/– 480 40 Tonnage formula 50 140 Nantet 2016: no 14 Ma’agan Mikhael ca. – 400 15.9 Reconstruction of the hull lines 25 110 Nantet 2016: no 17 El Sec – 375/– 350 20 Weight of the cargo unknown 250-280 Nantet 2016: no 18 Kyrenia – 295/– 285 23.3 Reconstruction of the hull lines 30-40 80-100 Nantet 2016: no 20 Chrétienne C – 175/– 150 40 Tonnage formula 29-36 80 Nantet 2016: no 21 Apollonia 1 – 150/– 80 24 Tonnage formula 30 unknown Nantet 2016: no 22 Carry-le-Rouet – 125/– 75 25 Weight of the cargo 60 unknown Nantet 2016: no 23 Dramont C – 125/– 75 14 Tonnage formula 24 58-90 Nantet 2016: no 24 Cavalière ca. – 100 22.17 Reconstruction of the hull lines 30 90 Nantet 2016: no 26 Bénat 2 – 125/– 50 3.3 Weight of the cargo 22 55-65 Nantet 2016: no 29 Le Miladou – 125/– 50 11.25 Weight of the cargo 25 – Nantet 2016: no 30 La Madrague de Giens – 75/– 60 402.5 Reconstruction of the hull lines 60-100 120-150 Nantet 2016: no 31 Kızılburun – 100/– 25 54-61 Weight of the cargo 40-45 140 Nantet 2016: no 32 Dramont A ca. – 50 111 Tonnage formula 55-70 unknown Nantet 2016: no 33 Planier 3 – 50/– 47 32-46 Tonnage formula unknown 120 Nantet 2016: no 34 Cap Béar 3 – 40/– 30 9.15 Weight of the cargo 40 75-95 Nantet 2016: no 36 Tre Senghe A – 30/– 20 58.2 Weight of the cargo 40 100 Nantet 2016: no 37 Comacchio – 25/– 12 59 Tonnage formula – 160 Nantet 2016: no 38 Ladispoli ca. 1 20.5-33.7 Weight of the cargo 40-45 180-200 Nantet 2016: no 40 Barthélemy B 1/15 2.1 Weight of the cargo 20-25 60-100 Nantet 2016: no 41 Saintes-Maries-de-la-Mer 2 1/25 21 Weight of the cargo 60 210-230 Nantet 2016: no 43 Chrétienne H 15/25 27 Weight of the cargo unknown 120 Nantet 2016: no 44 La Giraglia 15/25 33.6-38.6 Weight of the cargo 29-38 100-155 Nantet 2016: no 45 Diano Marina 40/60 50 Weight of the cargo 60 unknown Nantet 2016: no 49 Antirhodos Island 1/100 341 Tonnage formula 108 280 Nantet 2016: no 50 Dramont I 1/100 24 Weight of the cargo 50 – Nantet 2016: no 51 Lardier 4 50/75 6.5 Weight of the cargo 21 55-64 Nantet 2016: no 53 Herculanum 79 4 Tonnage formula 17-20 50 Nantet 2016: no 58 Napoli A 75/100 16 Reconstruction of the hull lines 32 86.3 Boetto & Poveda 2018 Calanque de l’Âne 75/110 50-80 Tonnage formula unknown 140-160 Nantet 2016: no 59 Tiboulen de Maïre ca. 116 270 Tonnage formula 55 204 Poveda et al. 2016 Saint-Gervais 3 100/150 81.133 Reconstruction of the hull lines 35 130 Nantet 2016: no 61 Grado 100/160 23-25 Weight of the cargo 25-45 unknown Nantet 2016: no 62 Monfalcone 1/300 140-200 Tonnage formula 45-55 90 Nantet 2016: no 65 La Bourse 160/220 142 Reconstruction of the hull lines 60 150 Nantet 2016: no 69 Ouest-Embiez 1 180/220 20 Weight of the cargo unknown 85-90 Nantet 2016: no 71 Torre Sgarrata 180/220 160 Weight of the cargo 72 80 Nantet 2016: no 72 Giglio Porto 200/225 30 Tonnage formula 35 100-130 Nantet 2016: no 74 Punta Scifo A 200/225 200 Weight of the cargo 80 unknown Nantet 2016: no 75 Punta Scifo B 200/300 347 Weight of the cargo 80 unknown Nantet 2016: no 79 Laurons 2 280/300 28.354 Restitution graphique 25 90 Nantet 2016: no 80 Chrétienne D 300/320 19.7 Weight of the cargo 25-28 – Nantet 2016: no 83 Pointe de la Luque B 300/325 50-65 Tonnage formula 30 130 Nantet 2016: no 84 Yassı Ada 2 350/400 100-115 Tonnage formula 42 125 Nantet 2016: no 85 Dramont F 380/400 9-11 Tonnage formula 30 85-100 Nantet 2016: no 87 Fiumicino 1 300/500 50 Reconstruction of the hull lines 30-54 60-120 Nantet 2016: no 89 Fiumicino 2 300/500 70 Tonnage formula 77-90 100-170 Nantet 2016: no 90 Fiumicino 3 300/500 27 Tonnage formula 23 55-67 Nantet 2016: no 91 Port-Vendres 1 ca. 400 78.740 Reconstruction of the hull lines 40 230 Nantet 2016: no 92 Dramont E 425/455 32.4 Reconstruction of the hull lines 30-40 100-180 Nantet 2016: no 93 Parco di Teodorico 450/500 4-8 Tonnage formula 25-30 80-90 Nantet 2016: no 95 Tantura A 480/600 17-22 Tonnage formula 25 95 Nantet 2016: no 96 Dor 2001/1 500/530 35 Reconstruction of the hull lines 35 104 Nantet 2016: no 97 Dor 2006 550/625 128-171 Tonnage formula 32 85-185 Nantet 2016: no 99 Saint-Gervais 2 600/625 40 Tonnage formula 25-30 220 Nantet 2016: no 100 Yassı Ada 1 ca. 625 55.765 Reconstruction of the hull lines 35 140 Nantet 2016: no 101 Pantano Longarini 600/650 200 Tonnage formula 50 unknown Nantet 2016: no 102

Measurements show the average size of the component, as far as publications provide such details. Where a double layer exists, the measurement includes the overall thickness of the planking.

(from Nantet 2016, updated with Poveda et al. 2016 and Boetto, Poveda 2018)

7While the data is neither uniform nor complete, it is possible to propose a comparison and make some comments. Unsurprisingly, the size of the wooden components of the hull is closely related to the tonnage: the bigger the ship, the bigger the frames and the planks. It is no surprise that the thinnest planks – between 17 and 20 mm thick – and the smallest frames – 50 mm moulded – were found on the Herculanum shipwreck (2 tonnes). On the contrary, the Madrague de Giens shipwreck had 120 to 150 mm moulded frames. The planking of her hull was 60 mm thick, even double-­layered in the bottom, reaching an overall thickness of 100 mm.

8Indeed, the decision to build a small or a large boat relies primarily on three main factors:

9– the traffic setting (scale of trade, direct route or redistri­bution);

10– the merchandise, according to the available resources and the needs;

11– the sailing conditions (winds and currents, depth of harbours, open or closed sea, nature of the coasts, etc.).

# 4. Changes in tonnage

12During the Archaic Period, tonnage does not exceed approxi­mately 30 tonnes, as evidenced by the Cala Sant Vincenç shipwreck. From the end of the 6th century AD, tonnage increased slowly but considerably during the two next centuries. In the Hellenistic and Late Republican Periods, the largest ships could load cargoes up to several hundred tonnes, such as the Madrague de Giens shipwreck (402.5 tonnes). Then, in the early Roman Period, the tonnage is still very high for ships carrying stone or wheat as part of state-sponsored traffic. But the tonnage of ships carrying wine, salted fish and olive oil seems to decrease. However, because of the scarcity of data, it is hard to determine precisely the changes in tonnage in the Byzantine Period and early Middle Ages. In any case, the idea that it would have dropped dramatically must be rejected.

# 5. Further factors impacting the size of wooden components

13The increase in the size of wooden components is not exactly proportionate to the tonnage. Further factors also impact the size of the frames and the planking, such as (fig. 1):

14– the function of the ship;

15– the tree species and the tools;

17– the architectural features of the shipyard;

18– the architectural type and the construction system.

Fig. 1:The various factors that impact the size of wooden components

19Indeed, this last factor appears quite important, since Greek Archaic boats, fastened with ligatures, were built with thick planks, usually between 30 and 50 mm. As for the frames, widely spaced, they are very high moulded in comparison with their tiny tonnage: for example, 100 mm for the Jules-Verne 9 shipwreck, although she could carry only 2 tonnes. A few centuries later, the Benat 2 shipwreck, which was found with a cargo weighing 3.3 tonnes, was fitted with a 22 mm-thick planking and circa 60 mm moulded frames. Even a large ship like the Madrague de Giens shipwreck was constructed with 120 to 150 mm moulded frames. After the adoption of mortise-and-tenon joints, it seems that the evolution of construction techniques did not impact the size of wooden components in the next centuries. For example, the transition from shell-first construction to frame-first construction, which changed the concept of the structure of the ship completely (Pomey et al. 2012), does not seem to have produced a significant decrease or increase in the dimensions.

Haut de page

## Bibliographie

Boetto G., Poveda P.
2018 “Napoli A, un voilier abandonné dans le port de Neapolis à la fin du ier siècle : architecture, fonction, restitution et espace de navigation,” in G. Boetto, E. Rieth, (eds), De re navali. Pérégrinations nautiques entre Méditerranée et océan Indien. Mélanges en l’honneur de Patrice Pomey, Paris, CNRS Éditions, Archaeonautica 20, p. 19-56.

Nantet E.
2016 Phortia. Le Tonnage des navires de commerce en Méditerranée du viiie siècle av. l’è. chr. au viie siècle de l’è. chr., Rennes, Presses Universitaires.

Pomey P., Kahanov Y., Rieth É.
2012 “Transition from Shell to Skeleton in Ancient Mediterranean Ship-Construction: Analysis, Problems, and Future Research, IJNA 41.2, p. 235-314.

Pomey P., Rieth É.
2005 L’Archéologie navale, Paris, Errance.

Poveda P., Sabastia A., Ximénes S.
2016 “Étude architecturale de l’épave Tiboulen de Maïre,” Cahiers d’Archéologie Subaquatique 23, p. 13-33.

Haut de page

## Table des illustrations

Titre Fig. 1:The various factors that impact the size of wooden components
URL http://journals.openedition.org/archaeonautica/docannexe/image/3800/img-1.jpg
Fichier image/jpeg, 93k
Haut de page

## Pour citer cet article

### Référence papier

Emmanuel Nantet, « The size of wooden components in relation to the tonnage of Greek and Roman ships »Archaeonautica, 21 | 2021, 365-368.

### Référence électronique

Emmanuel Nantet, « The size of wooden components in relation to the tonnage of Greek and Roman ships »Archaeonautica [En ligne], 21 | 2021, mis en ligne le 01 juillet 2022, consulté le 28 novembre 2023. URL : http://journals.openedition.org/archaeonautica/3800 ; DOI : https://doi.org/10.4000/archaeonautica.3800

Haut de page

## Auteur

### Emmanuel Nantet

Department of Maritime Civilizations and Leon Recanati, Institute for Maritime Studies, University of Haifa, Abba Khoushy Avenue 199 3498838 Haifa, Israel

Haut de page

## Droits d’auteur

Le texte seul est utilisable sous licence CC BY 4.0. Les autres éléments (illustrations, fichiers annexes importés) sont « Tous droits réservés », sauf mention contraire.

Haut de page
Rechercher dans OpenEdition Search

Vous allez être redirigé vers OpenEdition Search