Archduke Grand Excelsior $2,500 homemade semi-submersible

There are shed projects, and then there are shed projects. This is the latter. The superbly named Archduke Grand Excelsior is a homemade semi-submersible built by Cal Giordano from Alaska. The 32-foot vessel is built using a discarded 500-gallon propane tank, a recycled industrial buoy, some scrap metal, old trailer wheels, and a Johnson outboard motor. It weighs in at a hefty 3,000 lbs (1,360 kgs), and has a top speed of 10 knots.

The Archduke Grand Excelsior is a semi-submersible, meaning that it’s not capable of going fully under the water, but it can take its single occupant up to 8-foot below the surface, while the rear portion of the craft remains above the water. The vessel dives by adjusting the front bow planes downwards while moving forwards. This forces the cockpit underwater, however it can only stay underwater while moving. If the speed drops below 3 knots then it rises back to the surface.

Archduke Grand Excelsior semi-submersible

The sub’s builder, Cal Giordano, says the design was inspired by similar semi-submersible vessels used in the tourist industry, although he has adapted it to suit the harsh Alaskan climate. A steel cutting blade at the front of the vessel is able to smash through ice up to 4 inches thick.

The cockpit of the Archduke Grand Excelsior is basic, but features a display monitor showing a video feed from a camera mounted on the top deck so the pilot can see where they are headed while underwater. Air is supplied to the 4-foot (1.2 meter) wide cockpit via an electric-powered snorkel.

Mounted up front is a working homemade cannon. Yes cannon. Giordano says he only fires the cannon on 4th of July.

The estimated build cost for the Excelsior Grand Duke semi-submersible was just $2,500!

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