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Submarine 101

Types of Privately Owned Subs

Scuba Tow Sled

Tow SledNot really a submarine, but a good starting point.  The sled or "dive plane" is tied to a slow moving boat and the diver hangs on for the ride, controlling the angle of the sled to control side to side and depth.  Obstacles, snags, and no communication with the boat would be a problem, but they would be great for searching large areas as long as you did not need to stop frequently.  A nice add-on would be to build in a simple electric light signal system to signal boat operator.  The advantage is the dirt cheap price and the fact that and children could build this.  Otherwise they are also available from for $70.

Tow sleds were used to search miles of shallow, clear waters off the shores of the Turks and Caicos Islands, looking for the wreak of the Spanish slave ship Trouvadore bound for Cuba.  In broke apart on the reefs 1841 and all of the 193 slaves made it to shore and freedom under the British rule of the islands.  Most ended up working salt ponds and settled on the islands, where their ancestors live today.  See:

Diver Propulsion Vehicle or DPV

DPVAlso not really a submarine, but getting closer. The basic scuba tows is little more that battery powered boat trolling motors with an on/off switch. New they cost from $260 but several Do-It-Yourself plans are available. See  Scuba tows give the divers much greater speed and range.  And because the diver is not exerting energy swimming the available air supply will last much longer.  Keep in mind that you may need to return on your own if the battery goes dead.  Cave divers have drown when they used up their air supply trying to exit a cavern system after their tows stopped running after having assisted them deep into the cave.

Wet Sub

Wet SubA wet sub is the next step up from a scuba tow. A wet sub provides added protection for the divers.  More battery capacity provides greater range than scuba tows.  The occupants still breath from scuba tanks but additional tanks are often incorporated in order to increase the bottom time.  The divers can park the sub on the bottom and leave it with their own air tank.  Another advantage is wet subs allow the divers to transport cargo such as spear guns, metal detectors, and catches like catfish and lobsters.  The depth of wet subs is limited to scuba diving depths or about 120 feet, and the depth is controlled by first adjusting the amount of air in the sub's ballast tanks, and then fine adjustment are made with the thrusters.  If the subs thrusters are at the aft the forward momentum is needed in order before the steering is effective.  See More Photos...

Semi Dry Sub

Semi Dry SubNot being completely wet has its advantages.  Sitting in a semi dry sub your out of the water from about your chest on up, about like sitting in a hot tub. The top of the sub traps a pocket of air that allows the occupants to breath, talk, and view thought the windows without wearing any scuba gear.  Because air is compressed as the sub descends and because the occupants need to breath, fresh air from scuba tanks is constantly feed into the compartment at about 4 cubic feet per minute.  The excess air simply leaks out of a hole so the water maintains a constant depth inside the sub.  Since the top of the sub must be air tight you enter most semi dry subs, like the Resort Sub show here, by swimming up into the cabin.  The sub simply has an opening underneath, no hatch is needed.  Like wet subs, semi dry subs maintain their depth by balancing the amount of air in there ballast tanks against the amount of weight from lead and batteries.  It is important for semi dry subs to be maintain a constant volume of air in order to not upset their buoyancy.  The Resort Sub shown is equipped with vertical thrusters on each side.  These allow it to maintain control of the depth without constant adjustments to the ballast tanks.  It is very important to understand that even though the occupants are not breathing thought a scuba regulator, they are still breathing compressed air, nitrogen is still building up in their bodies, and a sudden accent is very dangerous.  So all of the rules an precautions for scuba divers also apply to semi-dry sub occupants.  The Resort Sub is manufactured by International VentureCraft Corp, and they provide a wealth of information on their web site: and will be glad to sell you one for only $44,000

Dry Ambient Sub

Dry Ambient SubDry ambient subs are just a simple step up from semi-dry subs.  Ambient means that the occupants are exposed to the pressure of the water surrounding the sub.  They ride in an air bubble, and like all air bubbles it want to rise to the surface.  The larger the amount of air then the larger the upward force.  That force is equal to the weight of the water that fill the space where the air is.  When you think about building a dry ambient submarine, it's a lot like thinking of building an aquarium.  A 100 gallon aquarium weights about 820 pounds.  That's a lot of weight pushing down on the bottom, so it must be built strong.  If you took the same 100 gallon aquarium and put it upside down in a swimming pool then filled it with air, it would be the same.   820 pounds of water wants to fill the aquarium and push the air out, so the air is pushing on what is normally the bottom of the aquarium with 820 pounds of force.  And your going to need 820 pounds to hold that aquarium down.  For the crew inside a dry ambient is breathing air that is under pressure so to the crew it's still just like scuba diving but they are are warm and dry. Herve Jaubert designed and built a complete line of dry ambient subs like the Explorer pictured here

Diesel Electric Dry Ambient Sub

Once there is a dry place to put an engine you can add a diesel to power the boat when it is not completely submerged.  Diesel engines are most commonly used because there is no danger of the gasoline vapors causing an explosion. The diesels are only good while they can draw air from the surface, but they use so much air that it is impractical to try an run them from air tanks, so electric motors are still used when under water.

My favorite dry ambient sub is DryDive.  She and her builder Brent Shaw,  hail from New Zealand.  Read more and see construction photos here: Dry Ambient Sub


1 ATM Subs

1 ATM SubBy far the most popular choice in home submersibles is the 1 ATM or 1 Atmosphere submarine. Dan H is launching his Kittredge; K350 pictured here. 

Standing on the sea shore we are subjected to 1 atmosphere of air pressure and once a 1 ATM sub is closes it's hatch the pressure inside does not change even when its dives. Typical maximum operating depths for home built 1 ATM subs is about 350 feet.  Depth is the 1 ATM subs greatest advantage, and by adding carbon dioxide scrubbers and supplemental oxygen a 1 ATM sub can stay submerged for days. However the 1 ATM is also one of the more complex and demanding submarine to build.


James from Guernsey, England is shown here standing next to his hull components. His web site; will quickly show the amount of work that goes into building a 1 ATM.  Another good site is John Farrington's Sub page. Both are building Kittredge designs from plans. This is a popular choice and is discussed in detail on the forum. 



You do not need $25,000 to build a sub.  Even a 1 ATM sub.  And you do not have to be an engineer. Tao Xiangli for Begin China, spent less that $5000.  Read more here: Tao Xiangli's Submarine



Interesting Variations from the "Normal" Sub

Wood  Hull, Dry Ambient, Bottom Crawler

Argonaut JuniorIn 1894, Simon Lake needed a cheap way to demonstrate his idea for a submarine so he built the Argonaut Junior from wood, canvas and pine pitch.  He used lead or iron for the ballast and air tanks from a soda fountain.  There was a hatch in the bottom that allow him to retrieve items from the bottom, proving to a skeptical audience that he had actually been on the bottom.  The best part is that it worked like a charm.  So if you really want to build a sub and don't have much budget, then follow Simon Lakes "can do" approach.  And we build and dove a recreation of Simon's Argonaut Jr. so we know. See Argonaut Jr. 2010


1 ATM Concrete Hull

Concrete Submarine

In 1994 Wilfried Ellmer built a 20 ton, 9 m long 2.5 meter diameter concrete sub with an 18cm wall thickness in the form of a blimp.  The photo show the sub being launched into lake Atter in Austria.  Concrete is actually a  great material submarines as you need a lot of ballast for a 1 ATM hull, and the compression force applied by water is exactly the thing that concrete does best.  So if you are in the market for a big, low cost hull, Wilfrend will be glad to hear from you. See more at




Deep Flight

Wings, aelerons, and tails work underwater too. Deep Flight is a commercial submarine developed by Gram Hawkes that takes advantage of this in order to give the submarine airplane like qualities. Deep Flight is positive buoyant and only stays underwater as long as it stays moving.  If slows down too much is stalls and rises uncontrolled to the surface, just like like an airplane.  See more at


Bionic Dolphin

The Bionic Dolphin is another example of a flying submarine.  Power by a large air breathing engine its submerge time is measured in seconds, but its surface performance is more that of a jet ski.  See more at:




Surface Planing

Hyper-SubPlaning is a trait know to speed boats and not submarines.  A boat is on plane when the hull lifts from the water enough to ride over its bow wave.  The heaver a boat is, the more horse power it will require to get it to plane.  Submarines are notoriously heavy because of the ballast weight required in order to get drop beneath the surface, so getting a 1 ATM submarine to plan is a remarkable achievement.  The Hyper-Sub, pictured here is built by Reynolds Marion and the first 1 ATM to achieve a plan using a staggering 880HP to do so. See more at

The Navy SEALS are the ideal candidates for a go-fast small submarine, and they have a diesel powered SPWS (surface planing wet sub) built for them by STIDD Systems. A wet sub does not have the ballast weight of a 1 ATM so the the available HP translates into more speed and range. The SPWS design criteria called for the ability to carry a six-man team and 1,830 pounds of gear up to 165 nautical miles away on the surface or 18 nautical miles under the surface. Surface speed is to be around 30 knots and submerged speeds are thought to be around 6 knots. 

Surface Planing Wet SubmarineIf your interest is in a garage build Surface Planing Wet Sub then you want a to follow Franck Iapichino's progress as he builds his wet sub out of a fiberglass speed boat hull.  He has added a water tight compartment for an 80hp yamaha jet-ski engine that will propel the boat on the surface. Franck's lovely wife Loetitia demonstrates the helm.  See more...




Dry Ambient Submarine Yacht

Dry Ambient Submarine Yacht

At $8 million a submarine can be just another ostentatious display but Proteus created by Herve Jaubert of Exomos is also an example of creative engineering.  "Displacement 45 tons, carries 10 people in the watertight cabin and up to 15 divers on deck. 1200HP diesel engine for surface and 200 kw electric motor for submerged transits. 300 miles range surface, 24 miles range under the water. Manned with 1 pilot and 1 engineer
Top speed 25 knts price tag: $8M"  --Herve Jaubert
See more photos...