Frequently Asked Questions | General Questions
is the advantage of Direct Drive surface supplied air unit?
design, simple is better. The Third Lung Direct Drive
units don't have belts and pulleys. Fewer components mean even
fewer maintenance concerns. More importantly, the Direct Drive
compressor can handle high RPM's and produce more air. Our older
compressors had to be stepped down by way of a pulley, as they
handled only half the rpm's that the engine generated. The result
is a unit that can provide an extended operating depth for multiple
Third Lung 275, 325 and the 460 look a lot alike. What are the differences?
325 and the 460 Direct Drive Third Lungs use different compressors
and/or engines and have differing number of diver sets. (A set
is the maximum number of divers that can descend to the deepest
operating depth.) The 275-DD is a single piston system on a 2.5
hp Honda that can support 2 divers from 45 to 75 feet. Its main
advantage is that it's only 32 pounds-- about the same weight
as a single tank SCUBA rig. If the divers must carry a system
over a great distance to get to their entry point, the 275-DD
would be very attractive.
active hooka diver would be well advised to select the 4.0 hp
Honda offered with the 325-DD. The 275-DD's 2.5 hp Honda engine
is working at full capacity during a dive. A complete overhaul
can be anticipated after 200 to 300 hours of operation. For many
recreational divers, this number represents years of use; to some,
a single season. The 325-DD has the same single piston system
that the 275-DD has but is mounted on a 4 hp Honda engine. Like
the 275-DD, it can support 2 divers from 45 to 75 feet. The 325-DD
comes standard with setups for three divers (estimated depths
for three divers is 15 to 30 feet.) It weighs 48 pounds. The advantage
of the 4 hp engine over the smaller 2.5 hp engine is the 4 hp
is actually quieter and works less hard, resulting in less engine
maintenance and repair. Overhaul is anticipated from 500 to 800
hours of operation. The 325-DD is a good choice for the more active
is a double piston system and produces enough air for 4 divers,
supporting them from 40 to 60 feet. It is also equipped for 4
divers. It uses a 5.5 hp Honda and weighs 55 pounds. The 460-DD
is the workhorse of the Third Lung's line and is the perfect selection
for the diver looking to get the highest possible performance
from a hooka system.
diving looks like snorkeling. Do I need to be trained?
True, Third Lung
diving is almost as easy as snorkeling. The freedom of swimming
unencumbered by SCUBA tanks will certainly remind you of snorkeling
or free diving. Still, whenever you breathe air while under water,
you are operating under a different set of rules. Training is
required for everyone who uses the Third Lung. The training could
be a traditional open water SCUBA certification course or a Recreational
Hookah Diver course. The latter course was specifically designed
for Recreational Surface Supplied Air Diving through the joint
efforts of both Third Lung and the National Association
of Underwater Instructors (NAUI).
Courses involve about 30 contact hours and can be completed in
as few as 5 days depending on available scheduling time for both
instructor and students. With proper training and proper maintenance
of equipment, hooka diving can be extremely safe. Third
Lung has been accident free since it's inception in 1969.
about diving wrecks or in kelp?
your use of a Third Lung to dive in overhead environments will
be limited. Only slight penetrations are possible, and they should
never be attempted without a back up air source. If you have evaluated
a dive site and been able to determine that a Third Lung is appropriate,
you can add additional hose lengths to increase your linear penetration
range. Always be aware that hooka diving follows different rules
than SCUBA; make certain that your air hose is free from potential
entanglement or damage.
Lung's advantage is that it is easy to find your way back out.
Just pick up your hose as you exit from the overhead environment.
The disadvantage is if the unit shuts down when the diver is exploring
an overhead environment, the diver is without breathing gas and
unable to make a free ascent. If you use your Third Lung in an
overhead environment, you should always carry an alternative air
source, such as the Third Lung egress system. Some situations would
also lend themselves to placing a safety SCUBA rig in reserve,
a common practice in any overhead diving scenario.
it hard to pull a Third Lung along the surface while diving?
be surprised, but there is less water resistance in towing a Third
Lung than in swimming with a full set of SCUBA gear. Considering
that most Third Lung dives are shared between two or three people,
swimming with a Third Lung is very easy. Conditions can increase
the drag; windy days may make towing more noticeable. Many people
simply drift dive on days when the wind is a bit strong, allowing
the surface unit to gently tow them along through a dive.
a Third Lung flip over?
Third Lung rides well on waves and is even built to take a splash.
If conditions are suitable for safe recreational diving, the
Third Lung will handle the waves. Breaking waves near shore, however,
are a different concern. A breaking wave in the surf zone or a
large wake from a boat could flip the Third Lung unit. The user must
seek safe operating areas as part of their pre-dive checklist.
If you are
diving from shore, a hands-on transfer through the surf is essential.
If you are diving from a boat, take special care in placing the
Third Lung over the boat's transom and into the water. You could
flip your Third Lung is it isn't lowered straight into the water.
When in doubt, consult the owner's manual for proper launching
happens if the engine stops?
should the compressor develop problems during a dive, the diver
might first be alerted of the air disruption when he or she no
longer hears the gentle tapping created while the compressor is
running. The tapping channels down the hose to the diver. If the
divers do not notice the cessation of tapping, then breathing
becomes restrictive at first, followed by an out of air situation.
In either case, the diver must begin an immediate slow ascent
to the surface. While free ascents from shallow depths are relatively
easy, they are not without risk. Too fast an ascent can result
in an pressure injury to a lung. Our recommendation is to have
a back up Egressor Air Reserve System for each diver. The Egressor
is standard in the XE package and is worn, hardly noticeably,
in the small of the back It provides a very small back-up SCUBA
reserve for emergency situations.
||How long are the hoses?
hoses run off of the compressor unit in stages. First, a 10-foot
heat hose cools the air as it leaves the compressor. A 60-foot
common hose connects to the heat hose, leading to a split that
supplies the 20-foot Diver's hoses. This system allows the divers
to swim apart but keeps them within 40 feet of each other. All
hoses use sturdy, reliable Quick Release Swivels that prevent
air interruptions caused by hose kinks. The hoses may all be attached
to each other in line, allowing a single continuous hose length
of 100 to 140 feet.
do you use a common 60-foot hose and then give each diver a 20-foot
hose? Why not give each diver an 80-foot hose instead?
the way the customer wants it, that's the way the customer gets
it. No arguments, no additional cost. Not only do our customers
prefer a single common hose leading off of the compressor, there's
a solid performance reason behind the design. More hose does not
create better performance. More hose equals more resistance (ore
work for the compressor), more buoyancy (more lead hose required
for the divers to wear) and more hose management (just a distraction
that gets in the way of your fun). Another key point is that the
diver's stay within 40 feet of each other. We think that it is
a lot safer than being able to separate by more than 100 feet.
shared hose eliminates these problems. While others might tell
you that separate hoses provide better breathing, be wary. We
still dive the common hose without ever noticing increased breathing
resistance, and we are happier that we have eliminated the hassles
that additional hoses create. Here at Third Lung, we
can configure the hose on your personal diving system any way
we want it-- but we'd suggest that you try the single common hose
before modifying your Third Lung to use multiple hoses from the
do you say that divers can descend "from 45 to 90 feet"?
Why the range?
people breathe differently. It would be misleading to state that
a system "truly" or "without a doubt" supports
a certain number of divers to a definite depth. While we could
quote one "best depth" rating, in the real world people
breathe at different rates. For instance, the navy averages a
diver's air consumption as falling within ‡ a cubic foot per minute
(cfm) to 1‡ cfm. That's quite a difference. The mechanics of determining
maximum depth are not complicated: the deeper you dive, the less
air you get from the compressor. The amount you will receive drops
by half in the first 33 feet. Four divers who breathe ‡ cfm each
can go deeper than four divers that breathe 1 ‡ cfm each. That's
why we use ranges. We want you to know before you buy.
can't I use a surface reserve tank attached to the Third
Lung for emergencies? Do I really need an egress system?
make bottles that attach to a Third Lung, they are not reserve
tanks. Instead, they are accumulators designed for commercial
application. A reserve tank is a back up air source, while an
accumulator simply allows the diver to work a bit harder at times.
Sometimes, with exertion, the diver can over-breathe the compressor's
capability to produce air. The accumulator allows the diver a
little extra air for short bursts. The problem is that the accumulator
silences the tapping heard through the hoses (a situation that
could be confused for an out-of-air emergency).
The diver will not know the compressor has stopped unless they
are communicating with a tender on the surface.
system, or some other pony bottle/SCUBA backup, is the safest
insurance against an out-of-air emergency. The Egress system's
Drop Weight CummerBelt fits comfortably around your waist and
and provides you with both a weighting system and an emergency
air source. Unfortunately, SCUBA tanks and regulators all cost
about the same, be it for a 14 cubic foot Egress bottle or a full
size 80 CF SCUBA tank. In spite of the cost, the Egress system
is the best possible backup for your family during their hooka
don't I see more Third Lungs around?
because you don't dive in South Florida or the Caribbean. Here,
in our backyard, the Third Lung is commonplace. You'll
see them in use by recreational boaters an on live-aboard yachts.
Some of the best lobster hunters in the Caribbean swear by their
Third Lungs. On the west coast, recreational surface supplied
air diving is relatively new.
Asked Questions | Operational Questions
doesn't the Third Lung have an intake filter?
filters that are supplied by the compressor manufacturer are plastic
housings with only a piece of felt as the filtering media. They
only filter dust, not carbon monoxide, water or carbon dioxide.
They do not provide an additional safety margin or relevant benefit
for either the diver or the machine while at sea. Also, the intake
holes point directly up, where rain and water spray may easily
enter. This position allows the felt to become wet or damp and
may lead to interior damage to the compressor. The felt filters
may also mildew if not changed, posing a potential health risk
to the diver.
We take the
felt filter housings completely off. We eliminate the dust catcher
in favor of a cap that keeps rain and seawater from entering the
compressor's air intake while reducing air intake restriction
to a true minimum. The results show with our unmatched performance.
We could leave the felt filter housing on-- if all we were interested
in doing was saving a buck. Third Lung, however, has
always spent that extra buck to do it right!
do you keep the exhaust fumes out of the engine?
Air is taken
in high through the remote intake "snorkel/flag staff" The exhaust
is low and exits the engine in the opposite direction being towed.
The engine fan, designed to cool the block, further creates an
air buffer between the exhaust and the intake.
compressors are tested and meet the same grade air (E) required
for scuba. Third Lung furthers the detail by adding
a DRY snorkel cap to the remote intake.
much maintenance is required on a Third Lung?
you need comes with the Maintenance Kit (standard to the XE).
Hose the system down, following owner manual instructions. Attach
the blower to the heat hose and dry the Third Lung quickly and easily.
Next, use Corrosion X
to lightly spray the engine. When everything has dried, put your
unit away. The regulators should be serviced yearly by any full
service dive shop. Follow the Honda owner's manual for maintenance
requirements for the engine.
heard that only a few compressors are designed for diving and that
most are for construction purposes. Is your compressor designed
for construction or diving?
neither statement is true. The manufacturers of oil-less compressors
do not have a specific design for diving or for construction.
How the oil-less compressor is utilized varies, just like any
other light engine. For instance, a gasoline engine might be used
to run a lawn mower, a go-cart, or in our case a Surface Supplied
Air diving system. It's still the same engine. The same is true
of the oil-less compressor. It has a myriad of uses. Please don't
be mislead. None of the manufacturers of oil-less compressors
used in the recreational dive industry certify these compressors
as air breathing or for diving.
adapts its oil-less compressors to withstand the harsh marine
environment as well as to provide the same quality air as required
for SCUBA (Compressed Gas Association Grade E). Don't believe
claims that one oil-less compressor is a diving compressor while
another is not. Ask for printed test results. It either meets
the criteria for air quality or it doesn't. The proof is in the
do you use plastic swivel fittings instead of metal fittings? Won't
fitting's swivel capabilities are limited at best. We used them
for years until we developed the plastic Quick Release Swivel
fittings. These QRS fittings are sturdy, will not accidentally
disconnect and eliminate kinks with their swivel action. The plastic
fittings have several additional benefits over metal fittings.
Metal fittings will oxidize quickly in the marine environment.
Third Lung QRS fittings will provide years of trouble-free
use. While it is possible to break a QRS fitting, we rarely receive
calls for replacements. If a QRS fitting does break, they are
inexpensive and can be replaced with a simple wrench.
the cases on your 275-DD and the 325-DD Third Lungs stand up to
the temperatures, UV exposure, and possible rough treatment that
one might expect on a boat?
want to waste your time with all sorts of industry figures and
jargon, but the 275 and 325 cases are manufactured of High Density
Polyethylene (HDPE) and will provide a lifetime of protection
to your Third Lung. The fact is, we've been using these cases
for years. We haven't had to replace a single case due to cracking,
U/V deterioration or melting. Any marketing claim by other manufacturers
that materials like Cross-Link Polypropylene are superior to High
Density Polyethylene is in the real world, simple balderdash.
We stand on our successful record of real-world use.
concerned about room on my boat. How much space and weight does
a Third Lung take up when stored?
largest Third Lung units take up much less than the equivalent
weight and space required for two SCUBA divers planning two dives.
The 275-DD, with cover, measures 17 inches by 24 inches by 17
inches. The Textilene Gear Bag is 28 inches in length and 12 inches
in diameter. The 275-DD weighs 32 pounds. The 325-DD, with cover,
measures 17 inches by 24 inches by 17 inches. The Textilene Gear
Bag is 28 inches in length and 12 inches in diameter. The 325-DD
weighs 48 pounds. The 460-DD, is mounted on a round dish with
a diameter of 18 inches. It is 15 inches high. The Textilene Gear
Bag is 28 inches in length and 12 inches in diameter. The 460-DD
weighs 55 pounds. With such compact dimensions, your
Third Lung can easily stow on any size boat.