However, this was all very well but something rather more substantial was going to be needed if the Allied fleet was going to be able to cruise back home with any sense of achievement.
The seond largest fortress in the Baltic theatre was Sveaborg, which guarded the approaches to Helsingvors, today Helsinki. Built by the Swedes, it was composed of a series of islets with rocky precipitous cliffs rising 30 to 40 feet sheer from the sea and thus very difficult to capture. The Russians had been able to take it in 1809 because the bay had frozen solidly enough to permit their army to cross the ice from Helsingvors and capture the islands piecemeal. Since then they had improved the defences to a level which had earned it the nickname 'Gibraltar of the North'. The whole complex was about a mile deep by half a mile wide. The three biggest islands, Gustavsfvard where the main citadel was, Vargoe and Oster-Svarto, were linked by stone causeways. The remaining islands were isolated. The two channels round these defences into Helsingfors were controlled each by a Russian three-decker anchored across the access, the Russland to the west, the Ezekielto the east. Around a thousand mines had been laid on the seaward side and especially in front of the entrance to the two channels.
On the 6th, following an updating reconnaissance by Sulivan, the two Admirals, Dundas and Penaud, decided to bombard Sveaborg, leaving a small force of fifteen assorted vessels in front of Kronstadt to keep the Russian Fleet bottled up. By the evening of the 7th their fleet had arrived off the fortress - it numbered 75 vessels including 22 gun boats and 21 mortar vessels. Dundas had decided that the defences were so strong that an assault was out of the question - equally a bombardment by the line ships was impracticable as their maximum range was well inside that of the more powerful shore batteries; the Russian gunners were well trained and would have blown them out of the water, even if they had survived a hazardous approach through the mines, sunken ships and natural obstacles of rocks and reefs. The admirals decided on a mortar bombardment and deployed at 4000 yards range in an arc facing the forts, eight British mortars, one per vessel, on each flank, and 10 French, two per vessel, in the middle. The deployment was laborious and dangerous, even for the shallow draught vessels, but by the morning of the 8th everything was in position. Each mortar vessel was attached by cable to one of a line of ships, moored half a mile back. In between, the four British tugs and two paddle steamers were lying ready to come to the help of any mortar vessel in trouble. For the moment the gunships were lying back near the towing ships. Also during the night, Penaud had landed a force on the undefended Abraham islet, situated directly opposite Gustavsfvard at a distance of 2500 yards, and in double quick-time had mounted a battery of four 27cm mortars there, with a plentiful supply of bombs well protected by overhanding rock.
