Chart correction N50/23 — chart 55042
55042 2Ed. 07/28/12 LAST NM N40/23 N50/23 Add Buoy Y, pillar, "X" topmark, Fl Y 3s with legend "Buoys (2)" [Q130.6] 41°03′23″N 28°12′48″E Buoy Y, pillar, "X" topmark, Fl Y 3s with legend "Buoys (2)" [Q130.6] 41°03′28″N 28°09′37″E (34(166)23 Istanbul)
Source: NGA U.S. Notice to Mariners · edition: 2Ed. 07/28/12
Reference information — always verify against official Notices to Mariners before navigation.