The 99 meter long, 4557 dwt chemical tanker Sabahat Telli became disabled in the Istanbul Strait.  The tanker was proceeding north through the strait when it suffered engine failure.   The crew contacted traffic authorities who dispatched tugs and rescue boats to the scene.  The Sabahat Telli was taken under tow to an anchorage in the Marmara Sea.  No reports of injuries, damage or pollution released.  The tanker was en route to Russia from Iskenderun.