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| Photo by Tanya Burnett |
As you finish your safety stop and start making your way topside, you
notice the bottom below is slowly drifting by. At the surface, you
don't see the boat because of the chop, but as you inflate your BC it
comes into view. You're surprised at how far away it appears. You roll
onto your back and start kicking. After a few minutes you turn over to
check your progress and a shiver of panic goes through you. You realize
you are actually farther away than when you started. You quickly think
of your options and the safety gear you are carrying-a signaling tube
and an air horn. What should you do first? Which one will get the
boat's attention? Will any of them work?
We decided to find out.
We contacted all major manufacturers and asked them to send us their
best "come get me" gear. We focused our review on two categories:
visual signaling devices and audible signaling devices. We then set out
to discover just how well they really work in the cold and unforgiving
vastness of the Pacific Ocean. Using a custom Radon 26-foot dive boat,
we spent two days off the coast of Santa Barbara, Calif., measuring the
visible range of signaling tubes and the audible range of horns and
whistles. The results were sobering, and at the end of the test,
everyone on our team left with a better understanding of the limits of
signaling devices-and a vow to brush up on underwater navigation skills
to avoid surfacing too far from the boat.
How We Tested Them
Signal Tubes. Eachsignal tube was first tested to find the exact depth to which it must
be submerged in order for it to remain in a vertical position. Each was
then weighted to simulate a diver pulling down on the tube to create
this stable position. We clipped each tube to an anchored buoy and
entered the buoy's position into the onboard GPS chart plotter. We then
motored east from the tube, stopping at distances of one-quarter,
one-half, three-quarters and one full nautical mile. At each distance,
the crew would scan the horizon to see if the tube was still visible to
the naked eye. With this data in hand, we then geared up and hit the
water to examine how a diver would pack, deploy, inflate and stabilize
each device.
Signal tubes were tested over the course of two days.
Conditions: Sunny, clear skies, sun at our back. Surface Visibility: 5 to 8 miles. Wind: Calm, no whitecaps. Swell: 1 foot. Searcher's eyes: 6 feet above the waterline.
On the first day, we attached each signal tube to a line at five-foot
intervals for side-by-side comparison. We placed the tubes in order
from tallest to shortest, and predictably discovered that the smaller
tubes vanished first.
Conditions: Overcast, sun at our back. Surface Visibility: 3 to 5 miles. Wind: Calm, no white-caps. Swell: 1 to 2 feet. Searcher's eyes: 6 feet above waterline.
On the second day, we deployed each signal tube by itself, simulating a
single diver adrift. Right away, we noticed that visible distances were
shorter than the previous day when there was direct sunlight and
multiple targets. The more conservative measurements taken on this day
are included in each review. Note, however, that with the sun at our
back, no whitecaps and small seas, conditions were as close to optimal
as you can get. In a real "come and get me" situation, the range of
visibility could be better or worse depending on conditions.
Audible alerts.
One tester was left anchored in a zodiac with a handheld VHF radio and
our inventory of whistles and horns. At various measured distances, we
stopped, signaled the tester to begin sounding each device, and
listened with the engine at idle to provide normal boat noise. The boat
was positioned downwind to offer optimal conditions. The maximum
audible range of each device is included in the reviews for comparison,
but it should be noted that in other conditions the range may vary.
Conclusions
While signaling tubes andaudible signaling devices do dramatically improve your odds of being
spotted, we were surprised at the limited range they offered, even in
our relatively good conditions. In general:
All signal tubes tested were visible at one-quarter nautical mile, and
about half were still visible at the half-mile mark. As expected, the
longer the tube, the greater the visible range. The largest tubes in
this test were visible at the three-quarter mark, and only one was
still visible at almost one nautical mile.
We also found that fluorescent yellow was very easy to spot in overcast
conditions while orange stood out in bright sunlight. Lettering on
tubes was not particularly helpful, and the black webbing tape that
trimmed the edges of most tubes only lessens the potential visibility
at greater distances.
Whistles were effective only to about one- quarter mile, with a few
discernible at a half mile, but all were still better than yelling,
which could be heard only at a tenth of a mile. Of the two air horns
tested one was stellar, blasting out its call up to one mile away.
Our findings suggest that you have a fairly small window of opportunity
to be seen if you're being swept away from the boat in a strong
current. If you surface in a two-knot current, for example, you will
drift a quarter mile in only 7.5 minutes. Think of the boat with rings
around it every quarter mile. Within the first ring you have a good
chance of getting noticed with most signaling devices tested here, but
once you pass the half-mile mark, the ability to be seen or heard drops
off significantly. If you surface already a quarter-mile downcurrent
from the boat, you only have a few minutes to deploy your signal tube,
sound the alert and get noticed before you pass that second ring.
Your odds are better with a very tall signal tube (eight to 10 feet),
which, based on our test, could make you visible up to nearly a mile
away. The higher the boat deck or point from which the searcher is
looking will also improve your odds of being spotted. If the searcher
is using binoculars (7 x 50 is standard for marine use), your chances
of being spotted double. But once you are out of visual and audible
range, it's a big ocean-an electronic beacon or EPIRB (see "Electronic Devices") may be the only way to get found.
The Reviews: Visual Signaling Devices
The SOS (Surface Observation Signal) is the original BC-integrated signal tube and still one of the easiest to use. Its hands-free design was the brainchild of underwater photographer Steven Frink (also photography director of this magazine), who often has his hands full with camera gear. The compact kit attaches to the BC's lower rear pull dump fitting and is secured by an elastic strap. To deploy, simply inflate your BC and pull the release strap-the tube inflates as air transfers from the BC bladder. We found it worked best to overinflate the BC to make sure the tube gets a good dose of air, then deflate the BC for more comfortable surface floatation. A one-way valve keeps the tube from deflating. A short elastic cord clips to a shoulder D-ring to support a vertical position of the tube, and a grommet on top allows you to attach a signal light or strobe. Price: $76. |
If we were putting together the perfect signaling kit we couldn't have done any better. Start with a six-foot tube that stands almost five feet above the waterline when you clip it to a lower D-ring for nearly hands-free operation; add a Wind Storm whistle that can be heard at a distance of one-half mile, and then throw in a signal mirror and 12-hour light stick just in case. It's also easy to use-the tube can be filled from a regulator, orally, or from your inflator hose. A built-in mesh pocket corrals all the accessories, and a full-length, two-inch-wide reflective strip provides better vis at night. Price: $75. |
The makers of the Dive Alert air horn knows that having more than one signal device is important, so they have added the SMB (surface marker buoy) to their product line. The bright orange tube also has two strips of Solas reflective tape (Coast Guard-approved) at the top, along with a loop of webbing to attach a light stick or strobe for nighttime rescue. It can be filled easily with a regulator or about six breaths. Webbing at the base can be used as a leg loop for vertical deployment. Velcro strips keep it rolled up neatly until needed. Price: $50. |
The Reviews: Visual Signaling Devices
The SMART (See Me And Respond Tube) is an integrated signal tube offered in five different models to accommodate a variety of different BCs. The pouch is slightly larger than the SOS pouch, and it attaches to the rear pull dump valve via a four-point buckle system, but it works just the same, drawing air from the BC bladder. A one-way check valve and an elastic cord system offer hands-free operation and keep the tube vertical for hands-free signaling. A strobe or light can be attached to the top with short pieces of cord provided. Price: $69.95. |
The yellow 45-inch Cordura signal tube (also available in orange) was the most compact tube we tested. While easy to stow and use, it was barely visible at a quarter mile. It can fit in almost any BC pocket or be clipped to your BC. The tube filled with one breath, and the screw-down inflator valve keeps air from escaping. Clipping the tube to a lower D-ring offered a steady, vertical position in the water and hands-free operation. It also comes with a safety whistle that we could hear at the quarter-mile mark and a clear sleeve for a light stick. Price: $29.95. |
The 72-inch Cordura signal tube comes in a compact, easy-to-stow package (it can be rolled up and stowed in a pocket or clipped to a D-ring) and offers very good visibility. It was easy to spot at a quarter mile and was still discernible at the half-mile mark. It inflated easily with two-and-a-half breaths and stayed inflated thanks to a locking oral inflation tube. Clip it to a low D-ring on your BC and it will maintain a vertical position with minimal support from one hand. It also comes with a diver whistle that was audible to a quarter mile. A clear sleeve can house a light stick, and Velcro straps keep the whole thing rolled up nicely. Also available in yellow. Price: $34.95. |
The PSD (Personal Safety Device) was the most versatile of the signal tubes tested. Orange on one side and yellow on the opposite, it also doubles as a floatation device. A patented zipper allows you to fold the tube around your neck and zip it together like a life vest, though it's not Coast Guard-approved for that purpose. As a vertical signaling tube, an adjustable webbing strap with a quick-release buckle loops around your leg to achieve a vertical deployment. The tube rolls into a compact package secured by Velcro flaps, and a clip is provided if you don't have pocket space. Two breaths into the oral inflator filled the tube quickly, and there's a clear plastic sleeve designed to hold a light stick. Price: $49.95.. |
The OMS BCA255 has a slightly wider profile than many signal tubes, making it very easy to spot at the quarter-mile mark and still visible at the half-mile distance. It rolls up and packs away in most standard-sized BC pockets. It was one of a few tested that could be inflated both orally and with a regulator-the bottom of the tube opens like a lift bag, and an internal baffle prevents air from escaping. It took six good breaths to inflate manually; but just a short blast from an octopus reg. A long loop of webbing attached at the base acts as a hands-free vertical stabilizer. After filling the tube, remove one fin and slip the loop over your foot and up to your knee. The weight of your leg acts as an anchor and effectively holds the tube upright. The OMS Emergency is essentially the same tube, only in a bright yellow color with the word "Emergency" printed on the tube. The neon yellow is unnaturally bright on the water and really drew our attention, though the lettering did nothing to help visibility. Price: $46.96. |
With about eight feet of tube visible above the waterline, the High Seas towered over all others and is the outright champ in the visibility test. It was the only tube in this test group we could see at three-quarters of a mile away, and it stayed visible to nearly the one-mile mark. The trade-off is bulk. It will fit into only the largest of BC pockets, and you'll need your own hardware to clip it to a D-ring. It takes about a dozen breaths to orally inflate, or you can fill the tube with a second-stage regulator. A long webbing loop fits around your leg for nearly hands-free use, and a strobe or light stick can be attached to a loop on top. Price: $98.02. |
The ResQBall offers a large target that might offer better visibility than safety tubes in certain conditions. Essentially a large balloon, the ball can be inflated to a diameter of about 3.5 feet, which is a whole lot wider than the 8.5 inches of the largest tube we tested. The caveat is that it's only 3.5 feet above the water and in high seas will be harder to spot in a trough. The company claims that it can be seen for up to a mile in clear conditions. From our small-boat platform, we were able to spot the ResQBall at the half-mile mark, but lost it by three quarters of a mile. The balloon and a power inflator adapter fit in your BC pocket and are easy to use. Inflating that ball requires about 300 psi and you leave it attached to the inflator hose for hands-free signaling. While it is possible to orally inflate the ResQBall (just like blowing up a balloon) in an out-of-air situation, realistically, it's not really practical. Price: $54.95 for inflator and one balloon. Extra balloons are $5 each. |
More Visual Options
If your day dive turns into a night drift then the Aqua Strobe might get you found before breakfast. If you are making night dives, it's a definite must to let the boat know you are in trouble if your light goes out. The Aqua Strobe is small and can fit most pockets, but also comes with a lanyard and Velcro strap for multiple mounting options. It will flash 70 times per minute for up to eight hours on one AA battery. Price: $39.99. |
One of the most overlooked and highly successful types of surface signal is a mirror. They're light, compact and don't need batteries. The Hot Shot is all that plus it's made from durable polycarbonate material so you won't have to worry about seven years of bad luck if you drop it. Signaling the boat is made easier by the center "site" that lets you see the reflection as a red spot when you look through the center hole. Just put the red dot on the boat and they should see the flash. We were able to see the signal from half a mile away easily. It comes with a lanyard, float and a USCG-approved whistle that we could hear up to a half mile away. Price: $11. |
The Reviews: Audible Signaling Devices
Sometimes getting noticed means making noise. From old-fashioned
whistles to air horns powered by compressed air, here are the best
options we tested.
Primarily designed as an underwater attention-getter, the Scub-Alert can also be used topside. This air horn plugs in between your inflator and low-pressure hose and makes a distinct high-pitched duck call. While it didn't travel as far as some of our best human-powered whistles, it was discernible at the quarter-mile mark. It is offered in three different models to fit various inflator designs, and prices vary depending on the model. Price: $59.99 to $69.99. |
It's the original integrated inflator air horn, and still the loudest we have tested. The company claims that it can be heard up to a mile away, and our results proved them right. The quality of sound is similar to the high pitch of a smoke detector alarm but 100 times louder. At this distance we couldn't see our "diver," but knew he was out there. Dive Alert is offered in three different models to fit a variety of inflators. Price: $50 with standard air couplings. |
Genesis has added a whistle to their popular purge snorkel, putting this signal device in close, easy reach. When you want to get noticed, just rotate the mouthpiece 180 degrees and blow. The medium pitch trill was audible up to one-quarter mile away. Price: $40. |
A traditional cop whistle that offers a nice high pitch that could be heard over boat noise up to a quarter mile away. Just zip-tie it to your corrugated hose and forget about it until you need it. Price: $9.95. |
This new compact whistle was one of only two that could be heard at a distance of a half mile from the boat. It's small, bright orange or yellow, and gets your point across with an ear-splitting trill. Price: $7.50. |
The bigger brother of the Storm, this was the only other whistle to grab our attention at the half-mile mark. Comes with split ring for attachment. Price: $9.95. |
Electronic Devices
In remote locations with high currents and an even higher probability
of being separated from the boat, you may need an electronic system to
ensure you'll be found. Here are two options.
Sea Marshall has developed a radio beacon system that is designed to help the boat locate a lost diver but that also operates on a standard search and rescue frequency (121.5 mhz) in case others are called in to look for you. The diver wears a beacon that is easy to operate, is depth-rated to more than 300 feet, and emits a direction signal that can be picked up by the boat up to 3 nautical miles away depending on the height of the antenna and sea conditions. The boat's receiving unit sounds an alarm when a diver activates their beacon, and indicates the direction of the signal. If the diver drifts out of range, the boat can then call in the Coast Guard. The locator signal can be picked up by search aircraft anywhere from 7 to 35 nautical miles depending on altitude, so even if the boat you're diving from doesn't have the entire system, the beacon itself could get you out of a jam. The base unit receiver is meant for permanent installation on a large dive boat, but Sea Marshall also offers a portable receiving unit that sounds the alarm if a beacon is activated, but it doesn't indicate direction to diver. Price: Diver locator beacon $349; Crew Guard portable receiver $658; Base Unit receiver, $2,795. www.seamarshall-us.com. |
The ResQFix is the smallest personal locator beacon on the market today, and the best way to get found from anywhere on the planet. It uses GPS technology to pinpoint your exact location and transmits this and your personal information to the Coast Guard. Each ResQFix is registered to its owner, so when it's activated they know who they're looking for. Designed for boaters, the unit is waterproof to about 16.5 feet, but it's small enough to fit in a compact waterproof box. If you are the kind of diver who ventures to the Galapagos, South Pacific or other remote destinations, this is a must. The ResQFix should only be activated in cases of loss of life or limb, as you will have the Coast Guard soon overhead. Price: $750. www.acrelectronics.com. |
How to Get Noticed
-a
signaling tube and an air horn or whistle. For maximum visibility in
all situations, it also helps to have a signaling mirror, too.
if you're drifting away from the boat. You may be out of visible range in a matter of minutes.
until you see some sign that the boat has noticed you. Multiple tubes
are easier to spot than individual ones. If your buddy has a tube, both
should be deployed. Different colors are easier to spot depending on
the conditions, have a yellow and an orange tube and deploy both for
maximum visibility.
attach the tube so that it remains vertical in the water, and start flashing your mirror toward the boat.
and you are close to shore or an island, swim in that direction. You
may be able to swim perpendicular to the current and escape its pull.
