When Vice Admiral Bakhirev received notification about this skirmish he dispatched the III Division Torpedoboat-Destroyers from Kuiwast to the Kassar Wiek, fearing a landing on Moon was imminent. The armoured cruiser Admiral Makarov, laying to the north near Kumora Buoy, was likewise ordered to lend support. To increase the range of her guns Admiral Makarov could be heeled over 5°. Likewise, Slava, at Schildau, could be heeled to extend the range of her 12-inch cannon in support, just as she had done in defense of the Riga Gulf in August 1915. During her winter 1916 refit the range of Slava’s heavy artillery had already been improved from 88 cables to 115 cables.
Meanwhile, towards midday, the five minesweeper boats promised the previous day from the II Minesweeper Division, reported to the I FdT, Kommodore Heinrich. They were sent to clear a channel in the mined area in the middle of the Kassar Wiek, the barrier laid by Pripyat, which was greatly hindering the freedom of action of the German torpedoboats. The bow of B98 and the wreck of Grom were still conspicuous above the water and served as good navigation marks. Soon the minesweepers found a ‘V’-shaped mine barrier beginning near Grom and stretching to the northwest and southwest. Most of the mines were of the 1908 type, spherical with lead caps and a charge of 150kg. At the beginning of the barrier were a few mines of the new 1912 type with a fat seam.
At about this time the small hospital ship Viola appeared on the Kassar Wiek, en route to the Kleinen Sound to evacuate the wounded of Section Winterfeld. The Russians took her for a troop transport and Vsadnik and the gunboats opened fire on her.
As the Russian destroyers of III Div TBD, Izyaslav, Avtroil and Gavriil, approached Raugen buoy they could make out Viola and the German torpedoboats. The I FdT had ordered his boats to withdraw to the west, but when the large Russian destroyers were reported he immediately took course towards them with his eleven craft.
At 1214hrs, as the range reached 65 cables (12,000 metres), Captain 1st Rank Shevelev’s destroyers opened fire on the nearest German torpedoboats. As the range fell to 10,000 metres the Germans returned the fire. Shortly after, at 1220hrs, the III Division TBD turned eight points (90°) to port and moved away to the east, maintaining fire from their aft guns. During the turn Avtroil was hit three times: one shell struck an oil bunker and two shells struck under the bridge, wounding some of the crew.
The waters which the Russian destroyers were negotiating were shallow and extremely tricky. Their freedom to manoeuvre was restricted and they were forced to travel at slow speed. At 1225hrs, moving under fire, Izyaslav and Avtroil scraped their screws on the bottom at a speed of 15 knots. By 1230hrs the firing had ceased. Izyaslav was sent to Rogekul for an inspection of her propellers and Avtroil went to Kuiwast to have the shell hole closed up.
Towards 1300 Kommodore Heinrich and his boats returned to their old anchorage, whilst the A-boats in the Kleinen Sound continued about their business, despite fire from Slava and the Woi battery, some of which was falling quite close to the small vessels. Slava fired a total of eighteen 12-inch shells. With the Russian fire being so accurate, the Germans decided that their observation post must be close by. Therefore T144, T160 and the A-boats undertook an hour-long bombardment of the houses and other positions on the western end of Moon and near Kaggowa.
The gunboat Grozyashchi also continued to fire until 1415hrs, shifting fire to the German torpedoboats. After all the firing of this day there was damage to Grozyashchi’s bow and stern guns; the first had its mounting damaged, the second had its mounting split, which was pulling it from the deck.
The battle on Ösel was drawing to a conclusion, with the last Russian resistance slowly being broken. Once the III Battle Squadron had broken through the minefields in the Irben Straits, the invasion of Moon Island would be able to proceed, probably on 17 October. Vizeadmiral Ehrhardt Schmidt still had the opportunity to further weaken the Russian sea forces in the Moon Sound and therefore he gave the following order by wireless to the I FdT, Kommodore Heinrich: ‘During darkness attack the Russian forces in Moon Sound and Riga Gulf with all means: the A-Boats are first to complete their task in the Kleinen Sound’. The previous day, torpedoes from other T-boats had been taken aboard Emden and serviced before being delivered to the A-boats by T160, so the small torpedoboats were now fully armed.
Before darkness fell, Kommodore Heinrich, aboard V100, went to the western exit of Moon Sound to see where the Russian guard forces were located. To the northeast was the armoured cruiser Admiral Makarov and near Kumora Reef lay five destroyers. However, once again Kommodore Heinrich baulked at the prospect of a night attack. He justified himself in his war diary thus:
I must refrain from a night attack by torpedoboats in the Moon Sound on this day. The A-boats have not yet completed their task in the Kleinen Sound: of the torpedoboat flotillas, the large boats of II Flotilla do not come into the question due to the difficult navigational conditions in Moon Sound, therefore only the 13th Half Flotilla remain. I hold it as premature to attack now – I must reckon on losses through mines or else stranding, without necessarily finding the enemy – I must for the moment employ myself with the security of the Kassar Wiek for Army operations.
It is odd that the I FdT discounted the B and G-Boats of II Torpedoboat Flotilla, as the majority of the Russian destroyers were of almost identical dimensions and displacement (although there had been several groundings of both Russian and German large types). Towards 1845hrs Kommodore Heinrich and his torpedoboats anchored near Pavasterort, whilst a squad of boats from 13 TBHF patrolled near the channel to Moon Sound.
During 16 October the German Naval Air Arm was also active. Earlier Arensburg had been established as a base for seaplanes and during the morning two torpedo-bomber aircraft took off on a mission against land targets, escorted by two single-seat seaplanes. Each bomber aircraft carried eight 60kg bombs and at about 1000hrs they attacked the base of the stone dam on Moon. The bombs fell between the Russian guns and their ammunition lockers and an ammunition fire started and was visible for a considerable time afterwards. Two Russian single-seat aircraft took off but did not press home their attacks. Russian reports state that the flyer Shteven met an enemy aircraft over the Kleinen Sound, but, after his third pass, his machine gun jammed and he returned home.