If you're one of the few lucky people with a heap of spare cash lying around, you can now purchase a Ego Semi Submarine from South Korea based Roanhaje. The Ego Semi Submarine your own personal submarine and with barely any instruction you be navigating the blue in no time. It's called a semi submarine because it doesn't fully submerge ever. The cockpit is submerged underwater but essentially hangs from two poontoons up top to keep everything afloat, so there is no chance sinking to the bottom of the ocean. Because it doesn't dive you can really consider this semi-submarine to be the ultimate snorkelling accessory. Giving you eye popping views of any surrounding wildlife. At around the £100,000 mark it is certainly the most expensive snorkelling accessory. It's designed to be environmentally friendly (well relatively) with two electric powered motors giving you up to 6 hours cruising about at 5 knots.