about 160 rifles, weaponry included a 75 mm field gun wz. 1902/26, two Bofors 37 mm anti-tank guns, four 81 mm mortars, and about 40 machine guns, including 18 heavy machine guns. Field fortifications were extended: more trenches were dug, wooden barricades were built, barbed wire was strung into wire obstacles, and reinforced concrete shelters were built into the basements of the barracks. Foliage was thinned to reduce cover on expected avenues of attack. The Polish defence, which anticipated principally a German land-based assault, rested on three lines of defence. The outer line included entrenched outposts (codenamed Prom, Przystań, Łazienki and Wał) which were to hold long enough for the garrison to mobilize. The second line of defence centred on five guardhouses (numbered I to V) in the center of the depot. The final defence comprised the headquarters and barracks at the depot's centre (sometimes referred to as Guardhouse VI). The Poles also had several supporting positions (Elektrownia, Deika, Fort, Tor kolejowy and Kej). The plan called for the garrison to hold out for 12 hours, after which the siege was expected to be lifted by reinforcements arriving from the mainland. On 25 August 1939, the German pre-dreadnought battleship , under the pretext of making a courtesy call, sailed into Danzig harbour, anchoring from Westerplatte. On board was a Marinestosstruppkompanie (marine shock-troop company) of 225 marines under Lieutenant Wilhelm Henningsen. On land the Germans had the SS Heimwehr Danzig force of 1,500 men under Police General Friedrich-Georg Eberhardt. In overall command was Captain Gustav Kleikamp, aboard Schleswig-Holstein. Initially, the marines were ordered to attack on the morning of 26 August 1939, on that day Kleikamp moved the battleship farther upstream, and as a result, Sucharski put his garrison on heightened alert. Shortly before the German disembarkation, the orders were rescinded as Adolf Hitler had postponed hostilities on learning of the Polish-British Common Defence Pact, signed the day before, on 25 August 1939, and that Italy was hesitant about its obligations under the Pact of Steel. Neither Eberhardt nor Kleikamp had specific information on the Polish defences. The Germans assumed that preliminary bombardment would soften up the fortifications enough for the marines to capture Westerplatte. Kleikamp had been assured by the Danzig Police that "Westerplatte would be taken in 10 minutes." Eberhardt himself was more cautious, estimating that "a few hours" would be needed to overcome the Polish garrison, which the