Mirabella V - believed to be the largest and most expensive yacht in the world - left Portsmouth on her maiden voyage on Sunday A good head for heights is needed atop the £30m yacht's 90m-tall mast The yacht was made in Southampton for US businessman Joe Vittoria, the former head of car hire firm Avis The interior was designed by Mrs Vittoria herself The yacht is heading for Mrs Vittoria's home town of Naples ====================================== Snippets of Related BBC Article: ....Mr Vittoria....The former head of car hire firm Avis then intends to charter the yacht out at a cost...