Introduction: Homemade Diving Apparatus

Picture of Homemade Diving Apparatus

This is essentially a small diving bell that fits over the user's head and allows him to descend to moderate depths. It does not protect the user from pressure, but could be easily modified to do so. It should be noted that I am not responsible for any injuries sustained while using this device; If, however, you take the proper precautions, the possibility of this is small, even in the event of a pressure failure. This helmet can be made from simple, inexpensive materials. It can be operated by two people, and with some design modifications, could be made self - contained. I have made sustained dives of over two minutes without a problem, at depths of approximately ten feet.

Step 1: Design

Picture of Design

This apparatus consists of a watertight helmet which partially encloses the diver's head, and is connected to a topside air supply by a hose. It is chained or otherwise affixed to a ballast weight to counter the positive buoyancy of the air trapped inside the helmet. It is very similar to diving apparatus used in the early days of ocean exploration.

Step 2: Helmet Container

Picture of Helmet Container

This is the main component of the apparatus. Any watertight container large enough to fit over your head should work; I found Sparklett's water bottles of the variety used in office water coolers to be particularly suitable. For those unfamiliar with these containers, they are large, clear plastic bottles about a foot and a half in diameter, and having a flat base, a mostly cylindrical shape, and a conical top terminating in a neck six inches high and two inches in diameter. I sawed the bottom off of one of these bottles to make my helmet. It is just large enough to fit over the diver's head, is transparent, negating the need to cut a window or porthole, and its neck provides a convenient attachment point for an air hose. A large plastic cement bucket would probably work too, but its lack of transparency would require the cutting of a viewing port, which would reduce the container's tolerance for pressure. You should pad the edges of the helmet to protect the diver's shoulders. I used two pieces of rubber hosing slit lengthwise and taped in place as pads.

Step 3: Air Hose

Picture of Air Hose

Many things would conceivably work here. I happened to use rubber aquarium hosing that I happened to have in a shed. This is about half an inch in diameter, and works fine. An old garden hose would probably be the most easily available thing. Just make sure you don't use drip irrigation hosing. It's riddled with little holes, and would leak A LOT. Other than that, just about any watertight hose would work. The way you attach it to the helmet and the pump will depend on the diameter of hosing you use, and the diameter of the helmet hose connection and bike pump nozzle. I'll leave that up to your ingenuity.

Step 4: Air Supply

In the first picture, you see a bicycle pump connected to the air hose to pressurize the helmet. If you use one, make sure it's a large one, capable of supplying enough air; an electric air compressor would probably work better and allow for longer dives. With my design, the diver must come up when the person working the pump gets tired. Probably, you could eliminate the topside air supply entirely and use a chemical re-oxygenation system inside the helmet itself, like on Isaac Peral - class submarines, and on the Columbiad projectile in Jules Verne's JOURNEY FROM THE EARTH TO THE MOON. If anyone knows how this could be done, feel free to comment!

Step 5: Ballast

Picture of Ballast

You'll probably need about 25 pounds of ballast to get the helmet to sink. Old U.S. Army ammunition boxes filled with rocks work great, but failing that, use your ingenuity. Test to ensure that your buoyancy is right, and you can ascend and descend with ease. Ballast could be attached directly to the helmet itself, or hung on a chain or rope, as I did. 19th century divers used cast metal helmets, contributing some weight, and also wore weighted boots and large weights around their necks, one at the front, one at the back, contributing weight (see image). Anything heavy would work; I used rocks, but old metal junk, bricks, cast- iron pots, etc., would probably all work if you had enough of them. Make sure you have a rope tied to the ballast to allow you to haul it out of the water, or pull up the diver in an emergency.

Step 6: Operating

Picture of Operating

Drop the ballast into the water, holding it just under with the rope. Have the diver drop into the water and put on the helmet, taking care to keep it level. Let the rope out, and pump continuously to keep the helmet pressurized. When the helmet begins to descend, the diver will feel a sensation like a rapid descent in an airplane, and the diver's ears might pop. After that, pressure should remain constant. If the water level in the helmet begins to rise, air is escaping faster than the assistant topside is pumping it in. Some air must escape to stop carbon dioxide buildup, But not too much, or the helmet will flood. A system using pulls on the rope to signal distress is probably a good idea. Make sure to observe proper safety precautions.

Step 7: Closing Notes

Many modifications could be made to this design; the helmet could be sealed around the diver's neck or onto a dry suit to increase pressure protection and allow for greater depth, although it should be noted that this would make it more difficult for the diver to remove the helmet in the event of an emergency. The topside air supply, as stated earlier, could be eliminated and replaced with a self contained air refresher. You could mod it into an awesome steampunk helmet! The possibilities are endless! be careful, and have fun!


ChrisB862 (author)2017-05-11

Never EVER do this. As a diver I'm breathing air out of a scrubbed tank - this "bike pump" method uses air that is supplied by an oil coated plunger. The oil particles are in that air - though you won't see them - they will be present. Oil and your lungs are a good combo. Never do this!!

steven13920 (author)2016-05-29

pretty cool, seen something like this on you tube

Dreistein (author)2010-10-21

i have got a air compressor,so what im going to do is make this but instead of a bike pump i will use the air compressor.

Proana (author)Dreistein2015-06-06

As others have said make sure your compressor either has a dryer to remove oil or even better doesn't use oil at all

Kirk (author)Proana 2015-10-25

oil-less is mandatory because of oxidation. At these low pressures the temperature is too low but scuba tanks have been filled with lethal mix (co - co2) from oil combustion in a compressor. Just filtering the oil out sets a bad habit.

Deutschmann (author)Dreistein2010-10-29

That should work fine, as long as the manufacturer of the compressor didn't use any strange, toxic lubricants, but that seems exceedingly unlikely.

xTOGx (author)Deutschmann2011-01-11

Builders, I am happy to see everyone interested in diving. I am a Salvage Diver by trade. Unfortunately, after reading this instructable I have identified some dangers. I DO NOT INTEND TO INSULT ANYONE...HOWEVER, I ALSO WANT YOU TO STAY ALIVE AND HEALTHY. I wrote everything, essentially, straight and to the point.

Hypercapnia - excess breathing of carbon dioxide that commonly gets caught in "dead space" of helmet. Note the difference in the Mark V dive helmet and KM-37. Over time, engineers reduce the dead space to reduce this danger. I suggest designing a lower profile helmet.

Asphyxia - simply put, lack of air to breath (in case compressor shuts off or leak in hose or what not)

Carbon monoxide poisoning - By using a regular compressor and not a diver's are compressor, which specifically uses lubricants and has an intake far far from the exhaust, you increase your probability of death. Consider it like breathing air from the exhaust of a car...not good. I suggest researching proper lubricants and different diver air compressors. Also, learn more about High pressure vs Low pressure compressors.

Decompression sickness - using the compressor will allow you to have more "bottom time." depending on depth and bottom time you may need to decompress, this allows nitrogen gases to be removed from your body. If you surface without decompression you may find yourself immobile. This is because a nitrogen bubble is trapped in the nerves that allow you to operate your legs, arms, or whatever it is that can't move. You then need to find a recompression chamber to shrink the bubble immediately. When treated hopefully the immobile body part will be able to move (expect loss of sensation). Aside from that, you can also die from Decompression sickness, depending if the bubble is trapped in your head or heart.

Pulmonary Over Inflation Syndrome - Air can get trapped between the lungs and chest cavity. This is more painful than anything else, see a doctor. If you do not regulate the air from the compressor with respect to minimum manifold pressure you may also over inflate your lungs. Think of the cartoon breathing in a balloon and over inflating. This also happens when you go from a deeper depth to a shallower depth with too much air already in your lungs.

Arterial Gas Embolism - Those going up and down 20 ft of water may find themselves within the cold grasp of AGE. Though different from Decompression Sickness it is treated the same as has many of the same dangers.

I made this list as short as possible. If you research each danger you will find greater detail. I encourage everyone to take a class in diving to learn how ti mitigate the dangers. I wish you all safe diving and good luck.

HalfFish (author)xTOGx2012-02-21

Hi, I am also a surface supplied air diver like xTOGx. I would like to confirm his warnings.

I google'd home made diving bell and found this.

I signed up just to confirm xTOGx and warn people that this is dangerous and not smart.
You CANNOT simply use a regular air compressor to pump breathable air. You will get sick and possibly die. If you survive you will most likely never dive again. You will become too sick with respiratory issues, or you will become too scared to dive from a scary experience.

If you want to experience this the RIGHT way, the way that is WORTH IT, then look up Kirby Morgan Helmets. Kirby Morgan makes industrial grade SSAir Diving Helmets. An even cheaper more recreational way are Bandmask surface supplied air masks.

Developing surface supplied diving helmets for military and industry use took decade of research and many many lives of divers. Even if you dont kill yourself, you can mess yourself up for life and prevent yourself from ever being able to dive again!

A guy who is certified to 1,000 foot depths.

Safetylast (author)xTOGx2011-02-11

what kind of safety and/or danger(s) should one consider if he/she had an air pump for in and one for out and has thinking of shallow dives (10 feet or less) for a time longer than a single breath?


ddzh (author)Safetylast2011-09-19

Long time ago one seaman decided to dive using cast-iron kettle as a helmet and stones as a weight. When he reached the bottom he dropped stones and came to surface. He managed to cry 'help' and lost his consciousness. Soon he died.

His mistake was that he held his breathe while surfacing. 3-5 feet and one breathe may be enought to seriously damage your lungs and die.

9w2xyz (author)Dreistein2011-11-26

Either one is not a good idea. Use Bellows. THe problem with pistons is that they tend to use oil as a lubricant. When it heats up under pressure...... it gets into the air. YOu ant to breathe that?

SeaPanther (author)Dreistein2011-01-23

Please don't do this. Unless it is for human use it can lead to mineral oils being absorbed through the lungs into the blood stream, damaging the lung lining and blood poisoning.

SubDude350 (author)2014-01-28

Cool system! I am attempting a small(ish) diving bell that works on basically the same principle! It is for shallow water though. Really shallow water...

burnerjack01 (author)2009-10-12

Another version is to use a 5 gallon bucket with a weighted collar. Bolt in a clear plastic viewing window with air hose entering from the bottom. CO2 will be forced out the open bottom.
 With ALL of these devices it is imperitive to adhere to these safety rules:
Never use alone but under ACTIVE supervision.
Never use any kind of compressor that uses oil AT ALL. This leads to suffication by coating the lungs preventing respiration. You cannot be saved once the lungs are coated.
Stop immeadiately if your vision becomes cloudy. I have played with this type of activity during my preteens and luckily survived.

Deutschmann (author)burnerjack012009-10-17

I prefer to just use a transparent helmet, as cutting a hole in an opaque bucket not only limits your field of vision, but also creates the possibility of a seal failure.  As for oil, I don't think most bicycle pumps have any; it would work its way out of the system to quickly to do any good, and I'm sure something bad would happen if you got oil inside a bike tire.  This device is perfectly safe if used intelligently.

Bike pumps usually have silicone grease made with petroleum products. Oil works fine in bike pumps if it is a type that doesn't deteriorate the seals or leather wipe (some use leather for seals).

arifshakeel6 (author)2013-08-03

If you are over 18 welcome to the Darwin Club but handing this to a kid would be criminal. You can breathe hold dive 100 feet and when you surface the lungs have the same pressure and volume they started out with. Take a breath in that bucket just 5 feet underwater and surface without exhaling and the lung would be stretched 15% greater in volume. If the weights you duck-taped on to yourself fell off the buoyant helmet would shoot you to the surface you have a good chance of tearing lung tissue tissue. People dived somewhat safely with this style equipment for 200 years but there was a reason the equipement was metal, weighed 200 pounds, needed a team and cost more than a home.

HackJob (author)2013-05-10

The change in pressure in 10 feet of water can cause an air embolism that will kill you DEAD - forget contaminated air - the gas in your blood expands blocks flow in the brain and that's it - lights out game over! This is not something to screw around with period - I strongly suggest this be taken down immediately before somebody kills themselves. This is beyond dangerous - as a Divemaster I'm begging you, don't try this.

geo909 (author)2013-02-26

Just a +1 to all those warnings. This has the potential of being very-very
dangerous and result to lung over-expansion (that's death) even in a
deep pool or poisoning from contaminated air, depending on how it is

If you like to explore the depths, try freediving or scuba diving and do
not try this, please.

I apologize for posting this to somebody's instructable, I know that they
probably spent a lot of time and effort on making it, but this can be fatal
in the wrong hands.

Fishnking (author)2012-12-01

You have to use ammonium nitrate or some such thing but it is toxic and will kill you when mixed with water

wagon173 (author)2012-11-20

I agree with most of these people. I have tens of thousands of dollars tied up in diving equipment and education and I'm still very very weary of home made scuba or umbilical diving configurations. You can embolize in 4 feet of water, in your pool maybe it'll take 5 feet. But if it doesn't kill you, it will definitely put a damper on any plans you have for doing anything for quite some time. Divers are notoriously cheap and I'm no different, but when it comes to the life support part, you shouldn't be. If you're interested in this type of thing, I highly reccomend you get certified and not stop with just an OW cert! There are plenty of fun DIY diving projects that won't get you killed. I like to make my own dive lights and DPV's. Right now I'm designing a submarine :) (That could get you killed lol)

Toga_Dan (author)2012-10-25

It should be noted that after breathing compressed air at depth, you must exhale while ascending. Holding your breath while ascending can injure your lungs.

At 10 ft depth, the air is 5psi. When you return to the surface, that air wants to expand.

I don't think you need to worry about the bends at 10 ft. I'm not sure what depth the bends can occur.

mouse23 (author)2012-06-07

Ever heard of snuba diving?
It is like snorkeling but the snorkel is attached to a hose which goes to the air supply, which floats on the water's surface.
I think if one only goes the depth of a swimming pool, just an air hose to the surface would be just fine. No?

ImageMaker (author)mouse232012-07-05

No. If the hose is long enough to contain a significant fraction of your lung volume, you'll fairly quickly faint when you try to breath through it, because you only get to rebreathe air already in the hose -- which is the same air you just exhaled. This could be solved by using two hoses with one-way valves; you'd inhale through one and exhale through the other.

Beyond that, however, your diaphragm can't draw air against water pressure, deeper than four or five feet; further down, you'll find yourself exhaling and unable to inhale (which, by the way, greatly reduces your buoyancy; you may have to actively swim to return to the surface, which rapidly gets more difficult when you're already out of breath).

The floating air pump systems work fairly well -- but some important safety features shouldn't be neglected. First, if you use a gasoline engine, you need to insure that your breathing air intake doesn't draw your engine exhaust (gasoline fumes will make you feel ill, but carbon monoxide can kill you). Second, you'll need a regulator of some sort at your mouthpiece, else the airflow and pressure from the air pump can rupture your lungs and potentially kill you. Third, the hose must be less than thirty feet long, to ensure you can't go deep enough to need to decompress. Finally, you need to have enough training in SCUBA diving to know things like the reason you need to exhale continuously as you ascend, else you can *still* kill yourself with one of these...

deepwaterhippy (author)2012-05-09

Same as HalfFish I only made this account to post as both he and xTOGx did, being another commercial diver myself. I suggest anyone doing or considering this to read their posts, due to the fact that the sight of this and resulting comments of buying random compressors and the like is enough to send a shiverdown my spine. Even in shallow water under the best conditions there is a great deal of danger to a surface supplied diver. One thing I noticed lacking from every post was something that should be fundamental law to EVERY dive and that is BACK UP. I don't just mean topside support, though that's always key. I mean there is 0 mention of a secondary breathing apparatus at all. Divers who dive anything whether scuba or a hat should ALWAYS have a back up plan. Commercial divers do this with a backup bottle integration but also have other back ups such as their pnuemofathometer which while normally just measures depth can be used as yet another breathing back up JUST INCASE. Many dive shops that sell commercial gear will actually do classes on teaching you the ins and outs of dive helmets. On that note I say be safe, and refine, who knows where the next great helmet could come from

techno guy (author)2011-03-04

I made my own equation for finding the weight in ponds of the ballast.

ballast (lbs)=(capacity in gallons of inner helmet * 8) + (-weight of helmet+5lbs)

snowluck2345 (author)techno guy2011-07-12

just wanted to point out its not realy "your equation", many people have probably created it before you.

techno guy (author)2011-03-15

Since the helmet has like 5 galons capacity, I calculated that the weight would have to be 44.5 lbs.

SeaPanther (author)2011-01-23

If you use it at any depth you must be aware that the air in your lungs will be at a greater pressure than atmospheric. If you return to the surface with the pressurised air in your lungs multiple forms of damage can result.


Kryptonite (author)2010-07-14

I really ought to try this one!

Doctor What (author)2010-01-13

 What a fantastically dangerous idea!  

Deutschmann (author)Doctor What2010-01-31

Opens up a whole world of unsafe possibilities, doesn't it?

SirNoodlehe (author)Deutschmann2010-04-19

Exactly how I like it

darkevilapie (author)2009-12-11

good job, me and my frend made something like this: we called it the diving bucket. but then we made a better one that doesnt uses large amounts of balast toget down. we used a gas mask from a army dump. maybe i should put it on instructables. also we used a pump for inflating airthingies and we are making an light for visior

Deutschmann (author)darkevilapie2010-01-10

Yes, post it, definitely!  Sounds way more awesome than mine!  Funny enough, I have an old air force high altitude breathing mask, but its probably not waterproof, and I would not want to try anyway.  It could be worth something!

darkevilapie (author)Deutschmann2010-01-31

:D thanks mate i will make an instructables.  and i think ur mask would do fine: if water gets in then the air will  pump it out :P
and im making more upgrades: my mask is about to get an auto pump made of an airco fan (the inflator of airthingis blew up) and the lights work underwater and our newest idear is an vacumcleaner for underwater to suck up stuff thats buried under sediment :) like my watch :(

Deutschmann (author)darkevilapie2010-02-01

Cool.  What do you plan to use it for?

darkevilapie (author)Deutschmann2010-04-01

wel i want to clean up our water so we can swin in it (lots of broken botles and iron shards in the water) and we just like to build things, we made more stuff and im planning to make a few instructables: this underwater breading mask (made a new 1)  , an crossbow (extreme power ) and more stuff if you think you want it here ( pipe for smoking or sommething like flametrower)

darkevilapie (author)Deutschmann2010-01-31

 ps. ow and i have clocked the time i was underwater: 43 mins (my frend was tyred)

Goodhart (author)2010-01-13

Would a filter of some sort be useful?   I mean, pumping any particulates in the hose, etc forcefully into that helmet could cause some serious distress

Deutschmann (author)Goodhart2010-01-31

I never had a problem, but it wouldn't hurt to put a filter from a painter's mask or something in there, just to be safe (I appreciate the irony of the word "safe" in this context).

Goodhart (author)Deutschmann2010-01-31
engineer_01 (author)2009-09-29

I can hold my breath for 2 minutes

Deutschmann (author)engineer_012009-10-01

I could stay down longer than that, I just haven't tried; My friend can't pump much longer than that, but I couldn't hold my breath anywhere near that long; we're both wimps.

stephenniall (author)2009-09-16

Hehhe i got a idea to run a compressor as the pump And Put a tap Wher eyou are so you control it

Deutschmann (author)stephenniall2009-09-29

I'm thinking of doing that, but all my compressors are the 12V car kind. I'll probably get around to it as soon as I find a 12V wall plug that has enough amps to run them.

stephenniall (author)Deutschmann2009-09-30

you should make a compressor tank out of a propane tank (search for ible) and do the tap to that after filling

Deutschmann (author)stephenniall2009-10-01

Might be cool. I'll have to try it; not really necessary at the depths I use this assembly at, but it would still be cool.

agis68 (author)2009-09-23

dude i had the same idea like you, but with some other details. 1 the container is metallic, inox maded to carry perssurized coffee (Illy). 2 i didn't use it for helmet but i place two belts from car safety belts so i can carry it. The air remains pressurised in the container and i can use it for 15-25 min. The basic is that has portability. I paced all the container in a solid base of cement and iron so now it can be sink. I don't use it for deeper than 4 meters cause the air pressure change dramatically....

Deutschmann (author)agis682009-09-29

Sounds cool, way better than mine. You should post it!

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