Cars for the surf and turf

Oct. 21, 2004
Amphibious cars might never be mainstream, but that isn't stopping developers from turning out new models.

Senior Editor

The Aquada from Gibbs Technologies uses an engine-driven jet to propel itself across the water at over 30 mph and with enough power to tow a skier.

On land, the three-seat Aquada has a top speed of 100 mph.

With the hydrofoils disguised as a rear spoiler and sideboards on the car body, Splash is a unique-looking concept car capable of 120 mph.

The Splash uses a compact, lightweight 750-cc engine that burns natural gas coupled to a three-bladed propeller.

Splash deploys a series of hydrofoils that generate enough lift to push the car out of the water as it speeds along at up to 50 mph.

Driving a car out on the open road gives most people the feeling of total control and limitless freedom. Others get that same feeling piloting a boat in open waters. So why haven't amphibious cars, a vehicle that lets drivers do both, ever really caught on?

According to Alan Gibbs, the businessman behind the Aquada amphibious car, in the future 15% of the cars sold will travel both on land and water. In the meantime, he and others around the globe are developing the technologies that will make such vehicles possible.

Gibbs and his company, Gibbs Technologies Ltd., got their start in Detroit where he assembled some engineering talent and came up with new ideas for the next generation of amphibious cars, ones that would go 30 mph or faster on the water. (Most previous amphibious cars did little better than 5 mph on water.) He took his company to England to take advantage of the low-volume manufacturing expertise in turning out high-performance vehicles and eventually finished the Aquada.

On terra firma, the Aquada is a good-looking convertible with unusually sleek and flowing lines. The only clues that something isn't quite kosher are the fully covered underbody, running boards but no doors, and an odd seating arrangement: a centered driver's seat flanked by two slightly set back passenger seats. (The seats are optimized for water-skiing, with a driver, skier, and observer.)

The engine, an MG-Rover's KV6, like those in the Rover 75, is a 2.5-liter V6 putting out 175 hp through an automatic transmission, giving it a top speed of around 100 mph and a 0 to 60-mph time of 10 sec. The engine was selected because of its alloy construction, light weight, and power density. It mounts right behind the passenger cockpit in a sealed box. This might be good for keeping water out, but makes cooling a problem, one the company focused on. With safety in mind, engineers installed hydrocarbon sensors in the engine bay, along with an automatic fire extinguisher.

Transitioning to water travel is as simple as driving into the water and pressing a switch. When the Aquada determines there is enough water under its keel, it retracts front and rear wheels using hydraulic struts. The struts, a Gibbs design, not only pull the wheels up and out of the way to reduce hull drag, but also act as self-leveling springs, shock absorbers, and bump-stops. The driveshafts disen-gage when the struts retract the wheels. And the tires, when tucked in, keep the vehicle from scraping its sides along piers and docks.

During transition, which can only be done in the water, thanks to safety interlocks, the car's road lights switch off and marine running lights hidden around the license plate come on. Dihedral trim tabs on both sides of the back of the car deploy. They lift the vehicle up in the water as it accelerates, letting it plane across the water more easily. Other features that contribute to Aquada's seaworthiness are three independent bilge pumps, a speedometer that works on land and water, and cleats integrated into the car body for tying up at docks.

When water-borne, the mid-chassis V6 powers a compact jet that spits out water with the equivalence of 2,000 lb of thrust, which is what it takes to get the Aquada planing across the water (in under 5 sec). The jet measures just 35 in. long and weighs 88 lb. It is fully enclosed to protect swimmers and a stoneguard prevents it from ingesting large objects. In operation, the jet's engine-driven impeller spins the water while stator blades and nozzles straighten and constrict the flow, creating the ton of thrust. A swiveling nozzle mounted on the stator nozzle directs the jet and lets the driver steer. In fact, the craft can turn in its own length with the steering fully locked one way or the other. If necessary, the jet can be run backwards, albeit at a reduced speed, giving Aquada a "reverse" gear in the water.

When designing Aquada, Gibb's engineers knew that car chassis are loaded at fixed points, such as the engine and suspension mounts. But speedboats spread loads across large areas of the hull. So they compromised, constructing a bonded aluminum chassis not quite tough enough for a car and bonding it to a composite hull not tough enough for a boat. The result is a hybrid space frame capable of supporting the Aquada on land and water.

The entire car is inherently buoyant and all components undergo 2,000 hr of salt-spray testing. The underside of the car or hull is specially shaped for lift with a keel fin for directional stability and chines and strakes that "grip" water in turns, giving it better maneuverability. The single-piece hull generates 3,850 lb of hydrodynamic lift at speed, which lets it get on top of the water. The chines, along with spray rails, also deflect water away from the vehicle and cockpit.

The car went on sale last year in Europe, having met all emission and safety regulations. EPA regulations are holding up sales in the U.S. It quickly set a new speed record for amphibian vehicles, 32.8 mph, eclipsing the old record of 9 mph set in 1996. The first person to buy one, British businessman Richard Bran-son, also broke a record, the fastest crossing of the English Channel in an amphibious vehicle. He did it in 1:46:06, smashing the previous record of 6 hr. And although it went on sale for roughly $230,000, an over-whelming response by the buying public led Gibbs to increase production and cut prices in half.

In landlocked (but lake-laden) Switzerland, Frank Rinderknecht and his team of designers at Rinspeed Design, a firm known for turning out high-tech concept vehicles, have created Splash, an amphibious sports car. It is said to be the first car that can "fly" across the water. It is powered by the MPE (multipurpose engine) 750, a 750-cc turbocharged natural-gas-burning engine from Weber Motor AG. The two-cylinder, four-stroke engine kicks out 140 hp, enough to take the ultra-light, composite-bodied Splash (1,815 lb) to a top speed of 125 mph on land. The car's bold styling, a head-turner on the roads, also hides the hydrofoils that let fly over the water.

A three-bladed prop swivel-mounted on a Z-drive hydraulically deploys from a compartment at the rear of the car and into the water, as long as the water is at least 1.1-m deep. The driver directs Splash through the water using the steering wheel, which controls where the prop is pointing. The prop is powered by the MPE Weber engine, courtesy of a transfer case that sends power to the prop, rear wheels, or all three, depending on the driver's choice.

When the driver hits the right button, hydrofoils hydraulically unfold and position themselves. The Formula-1 Type rear spoiler, for example, rotates 180°, creating a U-shaped wing behind the rear wheels. Hydrofoils hidden along both sides of the cockpit rotate down from just behind the front wheels. Once they are pointing straight down, each unfolds a second wing extending outward, forming a V.

The driver adjusts the angle of attack on each hydrofoil, letting him account for various water conditions based on practice and experience. At speeds below 19 mph, the car relies on its built-in buoyancy to stay afloat. Rinderknecht says the two-seat Splash goes about 32 mph in the water with the hydrofoils retracted. Buoyancy comes from a watertight body, several air chambers, a few cubic feet of buoyant material, an"'foils" deployed and at speeds over 20 mph, the vehicle rises up almost 2 ft out of the water &mdash enough to clear the tires. With little drag, top speed is about 50 mph.

The car was shown at last year's Geneva International Auto Show, but there are no plans to put it into production or build follow-on models. There is, however, some talk of setting a new record time for crossing the English Channel.

The original "car that swims"

Between 1962 and 1967, before product liability and pollution were much in the headlines, a small corporation in West Berlin turned out 3,878 Amphicars. Until recently, it was the only nonmilitary amphibious vehicle ever put into commercial production (i.e., over 50 produced). Most of the little four-seaters, at least 3,000 of them, were snapped up by U.S buyers eager to try it out on the highways and waterways. Estimates vary on how many still remain in some sort of working condition, putting it anywhere from 50 to 500.

The cars 1,147-cc Triumph engine located in the rear puts out 43 hp through a special transmission that accommodates travel on land and water. On land, the car can reach 70 mph. For water travel, a second transmission lever puts twin nylon propellers in forward or reverse, letting the car travel at up to 6 knots over the waves. The transmission can power the wheels and props one at a time or together. And the car uses the front wheels to steer on land and in the water.

Amphicars were constructed of mild steel assembled using continuous welds and lead filling around joints to make it watertight. There's a hull beneath the chassis, sealing all components in a (theoretically) watertight chamber. And the door seals used dual rubber strips that close together like seals on refrigerator doors. Water pressure helps force them shut and engage the seals. But in case of leaks, the manufacturer included a built-in bilge pump.

Some Amphicar enthusiasts blame the demise of the original amphibious car on poor marketing. It seems the company had no marketing staff, just engineers. It was also too costly, and no one had ever heard of a recreational/sports vehicle back then. It retailed initially for more than $3,300. For comparison, a 1962 Corvette cost about $4,000 and VW bug about $1,200. Later Amphicars actually had a lower sticker price, about $1,800. But the Amphicar's death knell was sounded by the EPA and DOT. In 1968 they enacted regulations on emissions and bumpers that did not let Amphicar export vehicles into the U.S., its largest market. Amphicar locked its doors before the end of that year.




Amphicars have a loyal following and there is a strong market in gleaming refurbished versions, as well as rust buckets. Originally, it came in four colors: Beach White, Regatta Red, Lagoon Blue, and Fjord Green (Aqua).

Hans Tripper began experimenting and built several amphibious vehicles for the German Army in World War II. Later, he formed a company to build the Amphicar, Model 770. (It has a top speed of 7 mph on water and 70 mph on land.

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