Yes Constantinople did have several shore batteries of varying quality, but the presence of German 'Advisors" greatly increased their efficiency, as demonstrated down flow at Gallipoli and in the Dardanelles.

The biggest threat to the Black Sea Fleet was far and away the Battlecruiser Goeben, a fully modern warship, crewed by Germans, and who'se Capt. essentially forced the Ottoman's hand into joining the war when he sailed off and began shelling Russian positions and shipping after the ship was "sold" to the Empire.

By 1916 though the addition of 2 modern Dreadnoughts to the BSF and the wear and tear on Goeben had shifted the momentum to the Russians but their lack of breakthroughs on land, lack of naval elan and daring, and perpetual shortages of material contributed to a lack of any daring plan. They DID however manage to mine the exits of the Bosphourous meaning that any ottoman movements were dangerous and had to be conducted slowly to with major resources to protect the Goeben. The fleet was then used primarily to shell targets in the Caucuses, and in late 1916 an internal explosion destroyed one of the 2 Russian Dreadnoughts, once again leaving them with an uncomfortably small margin of strength.

Then just months later the nation would dissolve into civil war, revolution, and ineffectiveness before leaving the war entirely.