Although not many details are known, the Fatimid-era Egyptian navy seems to have been well organized. The overall responsibility for the navy lay with the ʾamīr al-baḥr (commander of the sea), a rather elevated office in the hierarchy, with the administration entrusted to a special department (dīwān), characteristically named the dīwān al-jihād. The navy was funded by revenue from special estates set aside for the purpose. The total manpower reached some 5,000 men, divided into a system of naval ranks analogous to that of the army, with pay scales of two, five, ten, fifteen, and twenty gold dinars a month. In addition, the Fatimid fleet had a standing force of marine infantry for shipborne combat. The fleet seems to have been well trained, at least if the reports of elaborate fleet reviews in which manoeuvres and wargames were displayed for the Caliph are an indication. There is also evidence of the study of naval tactics on a theoretical basis, and portions of naval manuals, analogous to their better-known Byzantine counterparts, have survived. On the other hand, if the numbers reported by al-Qalqashandi come close to reality, and given the manpower needs of a galley, 5,000 men were insufficient to crew the larger fleets reported in the sources. This means that in times of mobilization, wide-scale impressment of civilian sailors took place—as is indeed indicated by some sources—which probably diminished the cohesion and effectiveness of the navy somewhat. In addition, Fatimid naval strength was hampered by the limitations of Egypt itself: a small coast with a relatively small seafaring population, and the lack of adequate lumber for shipbuilding due to the country's progressive deforestation, which was essentially complete by the 13th century. This placed a greater reliance on the woods of the Levant, especially Mount Lebanon, but access to these was lost with the onset of the Crusades.