Unusual failed attack off Nigeria - 1245Z 30 July 2013

The IMB reports the following unusual failed attack on an unidentified chemical tanker 47m south of Brass, Nigeria at 1245Z on 30 July 2013:

‘30.07.2013:1345 LT: Posn: 03:31N - 006:05E, Around 45nm South of Brass, Nigeria.
A gunboat claiming to be a Nigerian navy boat called a chemical tanker on VHF and asked details of vessel, cargo, last and next ports. This information was passed to the gun boat. After around 15 minutes the gun boat approached the vessel at high speed and demanded that the vessel be stopped and boarding permitted. Master informed that he would not be stopping as the area was high risk for piracy attacks. The gun boat threatened and followed the vessel for 20 minutes and then fired two shots in the air. Master immediately raised alarm over VHF and requested ships in the vicinity to relay its message to port control which was not responding to its calls. On hearing the VHF alarm the gun boat moved away. ‘

The colour key for Google earth images is:
Red - Hijacked vessel, kidnapped crew or attack in progress.
White - Failed or aborted attack.
Yellow - Pirate action group (PAG) or mother ship.
Green - Suspicious approach, incident or activity.