NAUTILUS MINISUB
WORLD’S
FIRST MANNED SCALE SUBMERSIBLE
WORLD’S FIRST AND ONLY
DISNEY NAUTILUS SUBMARINE

NAUTILUS
MINISUB after a successful proving test at the Benicia Marina, 1991.
“To
understand what’s significant about the NAUTILUS MINISUB, it helps to know what
the state-of-the-art in homebuilt subs was like at the time she was
conceived. Back then, some said it was
impossible.”
Pat Regan, Hawaii, 2005.
In the 1970’s and 1980’s, personal computers were in their infancy; we didn’t have the Internet resources we enjoy today; the first Human Powered Submarine Race had yet to be conducted; the term “Hydrobatic” had not yet been coined; information about submarine systems was extremely esoteric; and sub design math was the realm of nautical engineers.
In an episode of the 1980 TV show Cosmos, Doctor Carl Sagan (1934 – 1996) said, “If you wish to make an apple pie from scratch, you must first create the universe.” In a way, that summarizes the plight of the homebuilt submarine enthusiast during the last decades of the 20th Century. When I wanted to build a submarine, I first had to teach myself how it would work, and develop the math by which I would design it. And then I had to organize the manufacturing facility in which a sub could be built.
Contemporary Homebuilt
Submersibles: 1987 – 1989.

DENNOCH submarine, San
Francisco, California, 1991.
In the latter 1980’s, four Stanford University engineering students got together in a Menlo Park garage to turn a propane tank into a submersible they named DENNOCH. At the time, homebuilt submarines were so few in number that many people thought they were beyond the capabilities of amateur craftsmen. That public mindset is reflected in the motto painted on the DENNOCH tail fin, which reads: “Because it can’t be done.”

Close=up detail of DENNOCH
tail fin, San Francisco, 1991.
The builders of DENNOCH devised clever ways to overcome technological challenges. Today, the propane tank pressure hull, the general layout of the ballast tank plumbing, the lack of hydrodynamic control surfaces, and using a basketball to correct pitch variables, would all be generally frowned upon by experienced subbers Worldwide. But back then, those features weren’t yet recognized as shortcomings; they were considered innovations.

Port forward quartering view
of DENNOCH, San Francisco, 1991.
In its day, DENNOCH was pretty much the state-of-the-art in homebuilt submarines. Basically, people just wanted to prove it could be done. Accordingly, the designs they came up with had little or no aesthetic appeal whatsoever, and were based mainly on what the designer understood of functionality at the time.
NAUTILUS MINISUB: 1986 –
1991.

NAUTILUS MINISUB under
construction, 1989.
Independently developed in the 1980’s about the same time as DENNOCH, the NAUTILUS MINISUB was a quantum leap ahead. The pressure hull was an efficient steel teardrop spindle shape, adapted with a naviform cabin structure. The ornate NAUTILUS replica metalwork comprised or enclosed the ballast, propulsion, and guidance control systems. Adding to the challenge, there had never been a manned scale submersible prior to this one, and the Disney NAUTILUS was an unproven design some said was unfeasible. Many predicted I’d fail, and I was never entirely sure they weren’t right. But I had faith in my self-taught design math, and was determined to see the project through.

Screen Image from Walt
Disney’s 20,000 Leagues Under the Sea.
In replicating the Disney NAUTILUS, my graphic reference materials were limited to photographs of a TV screen taken while the rented movie played on a VCR; and a very poor quality Xerox copy of the tiny image of the Disney plans featured in Joel Frazier and Harry Hathorne’s 1984 Cinefantastique Magazine article on the making of 20,000 Leagues Under the Sea, which I enlarged to a size big enough to take measurements from.

Pat shaping the tail fin, 1988. (Do NOT try this yourself!)
Due to the large scale I was working in, I couldn’t simply trace the plans onto a piece of material and cut out the silhouette of the submarine as modelers dealing with smaller NAUTILUS replicas do today. Instead, I had to rely on a process of mathematical extrapolation and template making to produce the parts that would comprise this submarine. Without a computer, that work had to be done with a pen, a pad of graph paper, and a calculator.

NAUTILUS MINISUB on the boat
ramp, Benicia Marina, 1991.
When first launched, the NAUTILUS MINISUB utilized electric motor propulsion, manual “aircraft type” guidance controls, and a rudimentary form of SONAR to operate in zero visibility water. While subs like DENNOCH were designed to maintain a generally level attitude, the MINISUB’s Hydrobatic Ballast System enabled maneuverability through the full range of pitch variables: including vertical and inverted.

NAUTILUS MINISUB underway at
the Benicia Marina, 1991.
Thus, by 1991, we’d combined unprecedented utility and aesthetics to achieve an advanced homebuilt submarine that truly was in a new class all by itself: the World’s first Manned Scale Submersible. In doing so, we also proved the feasibility of the Goff / Disney NAUTILUS design as a manned, free-roving submarine. To date, the NAUTILUS MINISUB remains the only real submarine of Disney NAUTILUS configuration in any scale.

Pat Regan refurbishing
NAUTILUS MINISUB, Hawaii, 2003.
Today, as priorities allow, I continue developing the NAUTILUS MINISUB by replicating the exterior details seen on SFX models and stage sets used in the movie, and by making improvements to the operating systems. I’m also building functional replica 20K diving suits, and working on other scale replica projects of my own, as well.
Meanwhile, I am advancing the “Manned Scale Movement” in the Homebuilt Submarine and 20,000 Leagues Communities, to help people produce submersibles that are accurate scale replicas of famous designs from fiction or history. Presently, I am in contact with craftsmen wanting to build other Disney NAUTILUS submarines, and I’m helping them achieve that goal.

Peter Madsen’s submarine
KRAKA, Copenhagen Denmark, 2005.
In other parts of the World, subbers continue to advance virtually every conceivable aspect of homebuilt submarines. In Denmark, Peter Madsen and Claus Norregaard recently launched KRAKA: a submarine we call “manned scale” because it bears such a strong resemblance to a German WW-II U-boat. What an absolutely fantastic achievement!

Pat Regan and NAUTILUS
MINISUB, Benicia Marina, 1991.
Tomorrow? I believe Manned Scale Submersibles will continue to increase in numbers and popularity. If you’re wondering if you can do it, remember: it began in a small backyard shop, with one man doing what others said was impossible. There will always be obstacles to overcome, but the path becomes more clearly defined with every passing day. Homebuilt submarines will always be a challenge, but that’s part of the satisfaction in doing it. There may never be any guarantee of success, but you’ll never know unless you try. Only one thing is sure: it’s not impossible.