Why haven't submarine cars made a splash?

CONSIDERING how quickly automotive technology moves on and how closely the cars that appear in Bond films reflect innovations that will soon become a production reality, it's amazing that no company has yet cracked the market for a sportscar that converts into a submarine and back again.
When Pierce Brosnan pulled out a cellphone and used it to drive his BMW 7 Series in "Tomorrow Never Dies," people laughed. But exactly 20 years on, your BMW can indeed drive itself and with the touch of a button or the swipe of a smartphone screen will go and park itself or pull out of a space and pull up in front of you.
It's been twice as long since "The Spy Who Loved me hit the big screen" – it celebrates its 40th anniversary this month – however, a 2017 Lotus, no matter in which trim specification, still doesn't double as a submarine if driven at speed off a pier in Sardinia.
But that doesn't mean that companies haven't been trying to solve the problem of how to turn a car into a sub-aquatic means of personal mobility and most of them admit that the 1977 film was their inspiration for doing so.
Rinspeed sQuba
To date, the closest to a genuine submarine car is the Rinspeed sQuba, which is based on a Lotus body in a direct nod to the original.
It really can drive on land and on the sea bed. Unfortunately its wheels don't fold up. Rather the completely open-top car initially floats on the surface. Hitting a switch makes the car fill with water and submerge and a laser guidance system enables it to drive along the sea bed. However, the driver and passenger at this point will have needed to don masks and breathing apparatus.
The battery-powered car can manage 128km on land at speeds of up to 121km/h on dry land, or it can remain submerged at a speed of 2 knots and at depths of up to 10 meters, for three hours.
Gibbs Quadski
For those that want a vehicle that physically converts, look no further than the Gibbs Quadski. It's a quadbike on land and a jet ski, complete with folding wheels on water and is capable of doing 72.5km/h up to and beyond the water's edge. However, this particular aquatic vehicle will not submerge.
For those that feel quadbikes are too dangerous or uncomfortable, Gibbs also offers an aquatic open-top car that seats three. Called the Aquada, it can hit speeds equivalent to 48km/h on water and 161km/h on land and in 2004 was used by Sir Richard Branson to cross the English Channel in, in one hour, 40 minutes and six seconds, setting a new world record for an amphibious vehicle in the process.
WaterCar Panther
For those looking for something on-trend, US company WaterCar has started making a name for itself with its amphibious SUV the Panther. Though each one is a custom-built car, every model is capable of 88.5km/h on land and 71km/h across, but unfortunately not under the water. – AFP Relaxnews