The seeds of Tholstrup's adventurous streak were planted by meeting Thor Heyerdahl as a school boy in his native Denmark.
[1] His record, set between May and August 1970, starting and ending in Sydney, was all the more remarkable for having been achieved in an open 5.2 meters (17 feet) boat, a standard Caribbean Cougar runabout,[2] which he named Tom Thumb.
The boat, powered by a single 80 hp Mercury main outboard engine[3] and with a fuel capacity over 100 gallons, was purchased with funds raised selling his sports car.
[1] Twenty-nine years after setting his circumnavigation record, Tholstrup took to the sea again in another daring small powerboat voyage, this time from Darwin to Japan, in another 17-footer, a production Haines Signature 540 half-cabin[5] fitted with a long-range tank and additional buoyancy.
[2] Tholstrup devised the concept of the World Solar Challenge,[6][7] after, in 1983, having made the first transcontinental journey in a solar-powered car, crossing Australia in "The Quiet Achiever".