The latest underwater vehicle from the Netherlands-based submersible manufacturer U-Boat Worx, the HP Sport Sub 2, is also its most compact to date, requiring a footprint of just 71 square feet of storage space and weighing only 4,850 pounds—nearly 3,000 pounds less than the company’s next smallest sub. Because of its compact size, the sub can easily fit in the tender garage of nearly any yacht longer than 100 feet without a requiring a refit. It is also light enough to be launched and recovered with existing …