After the collapse of Sector IV, all forces that remained from Sector III fell back into the Martynovski Ravine, southeast of the Serpentine tunnel. The strongest unit – the 138th Naval Infantry Brigade – held the two railroad tunnels located on either side of the Serpentine and the western flank of Kolomiets’ perimeter. In the center, the 2nd Perekop and 79th Naval Infantry Brigade were both reduced to about 20 percent of their authorized strength. On the eastern end, the 25th Rifle Division still had two depleted rifle regiments and most of its artillery, but its right flank was open. Altogether, these forces amounted to perhaps 6,000 combat troops, and they blocked the direct path into Sevastopol from the north. Hansen’s LIV Armeekorps was in desperate need of rest and replacements, but he was still able to assemble some troops to keep the pressure on Kolomiets’ forces. Schmidt’s 50. Infanterie-Division was in the best shape of Hansen’s four divisions, so he deployed that unit to clear the Serpentine and the Martynovski Ravine, assisted by part of the 132. Infanterie-Division and the Romanian 4th Mountain Division.
By chance, two platoon leaders from the 138th Naval Infantry Brigade – Lieutenants Sultan Sultanov and Filip Onelytschenko – deserted to the Germans and provided the Ic of the 22. Infanterie-Division with the strength and dispositions of the remaining Soviet troops around the Martynovski Ravine.76
At 0530hrs on June 22 Hansen used this information to mount a carefully planned attack with the 50. Infanterie-Division, which overran the Serpentine and reached the railroad tunnel. German pioneers cleared out the tunnel with flamethrowers. Another GermanDuring June 24–28 both sides licked their wounds and prepared for the final round. Three Black Sea Fleet destroyers succeeded in bringing in Major Sergei E. Kovalev’s 142nd Naval Infantry Brigade over the course of two nights – the last reinforcements to reach Sevastopol. However, Kovalev’s 3,550 troops were not intended to reinforce the front line but to establish a defensive perimeter around the port in case an evacuation became necessary. The Stavka was already beginning to consider an evacuation if Petrov could not hold the city, and wanted to salvage troops for use in the Caucasus. Yet Petrov was now so short of troops that he committed five construction battalions to reinforce the defenses at Inkerman. Thousands of his troops were wounded and in the 47th Medical Battalion’s hospital, which was located in the champagne factory and catacombs at Inkerman. Now this hospital was on the front line, and there was no way to move large numbers of wounded. Most of his divisions no longer existed as such, and were reduced to regimental-size battle groups. Furthermore, Petrov’s air and artillery support was now minimal and it was clear that no more reinforcements would make it through the Luftwaffe’s blockade.
Although Manstein had gradually destroyed Petrov’s defenses piece by piece in the first three weeks of