In 1894, American inventor Simon Lake designed the Argonaut Jr., a wheeled vehicle that would drive along the seafloor, the only way to reliably navigate underwater at the time. The unusual concept has inspired sub aficionados ever since. Among its fans are Doug and Kay Jackson, married DIYers from Tulsa, Oklahoma, who in June built a watertight replica from lumber, lead and enough marine epoxy to overflow a bathtub.
Because no pictures of the Argonaut Jr.'s interior remain, making an exact replica would have been impossible. Instead, the Jacksons added a few modern touches while staying faithful to the basic design. Like its predecessor probably was, it is an ambient sub—it keeps the air pressure inside the cabin equal to the water pressure outside. Doug designed the narrow, tall sub using CAD software. The curved part of the frame is mostly 1x4 beams, while the underside is steel. For the rest of the hull, the couple found that four layers of quarter-inch-thick plywood pressed together by epoxy was the best mix of strong and cheap. For the 40-inch-tall, 4.5-inch-thick wheels, they cut and sandwiched together three layers of lumber and added leftover treads from a local tire shop.
The initial test dive started poorly when the trailer carrying the sub broke loose and careened into the lake. But the Jacksons recovered, poured a celebratory beer on the hull, closed the hatch, and took the Argonaut Jr. 2010 for its first successful drive, 10 feet below the surface of the water.
How It Works
Time: 8 Months
The operators lower a pair of anchors to the seafloor and, from the sub's single cabin, open a series of valves linked to six ballast tanks. Water floods the tanks, making the vessel heavier. An electronic anchor-winch controller winds up the cable, further pulling the sub down. As Argonaut Jr. descends slowly, an automatic air-pressurization system retrofitted to the craft draws air into the cabin from scuba tanks, equalizing with the ambient water pressure.
To surface, the operators drop the anchors (stored outside) again. Once those hit the floor, the sub rises. The Jacksons let out more cable and open valves that release compressed air into the ballast tanks, gradually expelling the water and making the sub more buoyant. "You open or close valves, and you go down or you go up," Kay explains. "It's really simple."
The Jacksons welded a trolling motor normally used for small fishing boats to the steel-pipe-based tiller. By turning the tiller's handle, they redirect the motor's propeller and turn the sub. They can also use a hand crank to drive the craft. The drivetrain consists of 30 feet of roller chain and matching sprockets, custom-cut from steel plates on their CNC machine. A dozen turns of the crank moves the sub about 10 feet.
The Jacksons received help from sub experts on the Internet, many of whom urged them to install a drop-weight system for emergencies. They ended up cutting or casting 3,500 pounds of lead blocks that fit jigsaw-like into the exposed steel frame on the bottom. If they need to ascend immediately, they can turn a handle that releases all the blocks at once. With 3,500 pounds shed, the sub, weighing a scant 1.25 tons, rockets up to the surface. The sudden change in pressure could cause the sub to explode, though, so Doug says that in all but the direst circumstances, "I'd swim out and leave the sub on the bottom."
The H2Whoa Credo: DIY Can Be Dangerous
We review all our projects before publishing them, but ultimately your safety is your responsibility. Always wear protective gear, take proper safety precautions, and follow all laws and regulations.
A nice craft and family project. From what I can tell from the photos, nice workmanship. I only have one suggestion, on the hand crank you need a few pieces of larger diameter pipe over the the crank rods to hold onto while you crank so you don't blister your hands as much.
As for exploding when the weights are dropped, I kind of have my doubts about that. You left the surface sealed with about 15-PSI and took it to the bottom. If you came up fast, you are still at 15-PSI, the only pressure difference is on the outside of the hull. If it were on the inside, you and the sub would be crushed.
Actually Phil the fear of the submarine exploding is well founded, since the pressure inside the hull is the same outside the hull at depth. Due to Boyle's law as the pressure increases, volume decreases; the ratio is about one Atm (15 psi ish) for every 33ft of depth at 1/Atm volume. So if the sub at 1 atm (surface) dove 99ft (3 Atm)the air in the sub would take up 1/3 the space at depth. however this sub matches the pressure outside so it won't crush so it has 3 Atm pressure at the full volume. If there is a rapid acsent to the surface the air in the submarine will expand to match the surrounding pressure and blow the submarine apart at depth. It's the same reason scuba divers have to exhale as they surface. Their lungs could overexpand causing serious injury or death.
DanMechEng, very nice description, but I believe the pressure at 30 meters is 4 Atm. Surfacing from this depth, air should expand 4 times it's original volume (as opposed to 3). This is only a minor detail.
wjrussell, Dan and you are both right, just different points of reference. Dan is referencing gauge pressure, you are right with respect to absolute pressure. Dan's is more correct for this instance, as the craft is not starting with a perfect vacuum inside on the surface, so a gauge reference (1 atm.=0 gauge)is more appropriate.
And to the Jackson's my congratulation, you are every bit of whom T.R. was talking about:
It is not the critic who counts, not the man who points out how the
strong man stumbled, or where the doer of deeds could have done them
better. The credit belongs to the man who is actually in the arena;
whose face is marred by dust and sweat and blood; who strives
valiantly, who errs and comes up short again and again; who knows the
great enthusiasms, the great devotions, and spends himself in a worthy
cause; who, at the best, knows in the end the triumph of high
achievement; and who at the worst, at least fails while daring
greatly, so that his place shall never be with those cold and timid
souls who know neither victory nor defeat. - Teddy Roosevelt
"It's a trap! Are ye blind?" Yep, it's a deathtrap, certifiable. The history of home built submarines is not pretty. Salute then scuttle.
Dang OldCarGuy, that's a nice compliment. Makes me feel a lot better about all the stuff I do that does not work. :) Thanks. And it's really heart warming to see people discussing Boyle's law. Best of luck to each of you and your projects.
Hey Nicholson, didn't you read the disclaimer? Keep your bike helmet on and don't make any left hand turns. :)
Doug "Death Trap" Jackson
Skipper, Argonaut Jr.