THE PIRATE RISK
PIRATE GEOGRAPHY
Although the bulk of the pirate risk is in the Gulf of Aden and concentrated adjacent to or within Yemeni coastal waters, the adjacent map clearly demonstrates that Somali pirates do not restrict themselves to Somali coastal waters and in fact have been known to attack vessels more than 1000 kms offshore and as far south as Tanzania.
 
The latest IMB Piracy Map showing all attempted and successful hijacks in the GoA and offshore Kenya, Tanzania and Somalia, can be found by clicking on the above link.
LIKELY RISKS in the course of a hijack, include:
Firearm Risks - serious injury/fatality or damage to cargo, fire risk (especially if the tanker is carrying hydrocarbons) and environmental risks.
Protracted Vessel Hijack can have a range of effects on the vessel's crew :
Assault by a hijacker leading to serious injury
Poor food leading to illness
Illness/injuries that cannot be treated properly during hijacking, leading to long term/permanent disability and/or fatality
Mental illness
 
PIRATE TACTICS
We are now seeing changes in pirate tactics in order to divert those Naval warships that are escorting convoys, by the use of decoy pirate vessels to carry out ''dummy'' attacks on certain vessels in the convoy, in order to capture an ''easy target''. The diversionary attack which led to the capture of the LPG tanker Longchamp on the 29 January 2009, demonstrated that naval warships do not provide conclusive deterrence. In this case, the naval escort was attempting to cover too many vessels and at too long range. There were also no security professionals onboard that could have delayed attempts by the pirates while the escorting Naval warship was distracted responding to the perceived pirate target. 
SOMALI PIRATE RATIONALE
For an in-depth understanding of the Somali piracy phenomena which is well-elaborated in an 11-minute video documentary presented from Eyl, the capital of the pirate stronghold of Puntland, go to this link -  Pirate Haven