World’s Fastest Amphibious Car

World’s Fastest Amphibious Car

According to seller Fantasy Junction, Project Sea Lion Prototype (developed 2006-2012) combines a custom-built aluminium and stainless steel body with a Mazda 13B rotary engine meant to set the record for fastest land-sea vehicle. Unfortunately, the new record calls for 60 mph on the open water, and if I'm reading the listing correctly, that would require a Sea Lion upgrade to a newer Mazda rotary. The Sea Lion's transformation to naval operations is impressive, from sidepods and folding prow to retractable wheels, but the cabin does appear to be a little warm on the road, since it lacks any ventilation aside from driving with the top hatch open.

There are approximately 25 current contenders in the world with a variety of designs and capabilities. Each year, one builder proclaims their performance is superior to the rest, and they display their data through public announcements. The competition is unofficial, and participants enjoy the freedom of having a complete lack of rules. Various extreme designs are continually explored; each has measurable benefits as well as drawbacks. For the most part, a GPS display with a YouTube recording is internationally accepted as “valid” for speed documentation. There has been talk of creating a corporate event, similar to Burning Man or Kinetic Sculpture Race, which records and awards the competitors with specific acknowledgements. This, however, may be more of a detriment than assistance. The addition of Rules and Requirements always diminish scientific achievement and exploration. And it just plain ruins all the fun! If a neutral party is required to settle a performance dispute, “Guinness World Records” is available to record and bear witness to any new achievement. So at least at this time, there does not seem to be a need for any larger event organization. Guinness World Record Sea Lion was designed using CAD software and spread sheet calculations, by M. Witt. The vehicle is primarily, TIG welded 5052 Aluminum constructed from CNC plasma burned shapes and other CNC milled components. It has an integrated monocoque welded uni-body center section. There are removable side pods, used for floatation and cargo, and removable fenders front and rear. With few exceptions, there are no structural parts borrowed from other vehicles. The design is created from a clean sheet of paper, and was calculated to exceed previous speed records. When the project began, in 2006, the top water speed was 45 mph and the top land speed was 125 mph. Today, the land speed remains unchanged, but the water challenge has risen to 60 mph.

There is a wide spectrum of different vehicles competing. Some vehicles are very fast on land but slow on water and others are the reverse. Some of the more unusual designs use tank tracks and have had surprisingly fast results on both water and land with the propulsion being only the tracks. (No propeller)

Sea Lion is currently configured to be World’s Fastest Amphibious “LAND SPEED” vehicle. The transaxle is geared for speeds in the 180 mph range. The car has an extremely small frontal area and very aerodynamic shape. It has great potential to hold the land record for many years to come.

The water speed is currently limited by horse power, and it is up to the next owner, as to how extreme the next power plant should be. The current engine is a Mazda Rotary 13b (1974 –smog exempt). The engine should be upgraded to a Renesis Rx8 unit, and the old engine saved for an SB100 registration, at some later date, if that becomes a goal for the owner….

Building Sea Lion has been an enjoyable exploration. I have provided the basic architecture for the car and resolved every conflicting interaction between Car and Boat. The next chapter of this project is to provide an ultimate engine and begin speed trials. There are many highly qualified Rotary Engine builders who have decades of experience making reliable high performance improvements. It is best to bring a specialist builder on board for the rest of this endeavor and bring the car up to its full potential.

The builder (M.Witt) is willing to work with the buyer on all future modifications and is willing to remain available as a consultant, engineer, machinist and psychiatrist for whoever decides to venture further into the amphibious record books. The car comes with a number of accessories and earlier prototype parts. As a racing car, this Sea Lion is sold on a bill of sale only.


  This car is currently for sale at Fantasy Junction.

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