A 40-year-old New Zealand man has been killed by a blade from a home-made hovercraft.

Police have said the blade came loose and struck Alastair Senior in the back of the head (the accident was originally reported to have decapitated the victim). Senior had “spent years” building the device in his garage, according to the New Zealand Herald.

Sergeant Colin Nutall of the Waitemata Serious Crash Unit told the NZ Herald the death resulted from “a structural failure” of the craft.

The hovercraft’s design apparently imitates what’s called a “swamp boat” in the USA, with a propeller attached to an A-frame at the rear of the boat. This A-frame structure is believed to have failed after Senior had taken the boat out on the water following successful tests at home.

Private hovercraft are not regulated in New Zealand, according to the NZ Herald report. According to Sergeant Nutall, no license is required to build or operate hovercraft unless they’re used on public roads. ®