We headed down to Trefor pier along with 4 divers from Bradford Uni BSAC. The day was a perfect day for diving with no winds, calm seas and a sunny sky. Trefor Pier is one of the most popular dive sites on the North Wales coast and for good reason. It provides excellent diving whether you are a novice doing your 1st sea dive in the UK or a more experienced diver. It is also a great site for photographly as marine life is exellent. Trefor is best dive about 1/1-5 hrs before high-water. Which is approximately 2 hrs before Liverpool’s high-water(GMT). A southerly wind is best for good visidility which can be up to 10 meters. On a spring-tide maximum depth can be up to 7 or 8 meters and low-water is about 4 meters. 

 Mac was suffering from a synus infection so wasnt diving which left Kev, Jac and me in the water.

The dive starts as you enter the water at the breakwater steps and swim alongside the harbour wall. Trefor Pier itself was built in 1912 and closed in 1971. The wooden pier is about 70 meters long and 8 meters wide and built at the end of a stone breakwater. Vis was less tan perfect but just about doable. As we rounded the corner of the breakwater wall we encountered a little bit of a swell, we found one of the pier legs and turned right to head out the length of the pier. The sea bed under the pier alternated between bare sand to large pebbles around the legs, there are bits of metal work and some beams on the seabed between the legs all good hunting ground for that illusive snap. Vis hadnt improoved but if you looked closley you could see some of the areas abundant sea life. We spotted quiet a few scorpion fish that just sat up and posed for us, even with a couple of lights shon on them, velvet swimming crab tucked themselves in various nooks and cranies and even a small eddible crab showed up for our little photo shoot.

The site has an emergency phone just incase the worst happens, there are toilets but these are only open between April and October. There are picnic tables b y the waters edge which are not only handy on the surface interval for sitting sown and enjoying Jacs soup but are great for stranding your kit on while you walk off to your car.

The general concensus is that Trefor is a cracking little dive site and def deserves being in the UK top 100 dive sites. It will be a place we go again hopfuly next time the vis will be a bit better.

Marine life hotspots off the British coast are facing a double threat — deep-sea trawling and acidification of the oceans — a leading scientist warned yesterday.

The rich biodiversity of seamounts (underwater mountains) and cold-water coral reefs, which science has only recently begun to understand, needs urgent protection, Jason Hall-Spencer, of the University of Plymouth, said.

Seamounts are volcanic mountains that rise at least a kilometre above the sea bed. Together with cold-water coral reefs, which often cover seamounts, they are among the most important marine habitats, where new species are regularly discovered.

There are about 50,000 seamounts worldwide but only about 1 per cent have been explored. The ones in British waters include Anton Dohrn off Rockall, home to species such as pollock, cod, hake, monkfish, redfish, squat lobsters and oreo fish. However, these fragile ecosystems are in danger of being lost before they have been properly investigated.

Scientists for the Census of Marine Life, an international project cataloguing ocean organisms, say that many seamounts and cold-water reefs have been damaged by trawling and that others are vulnerable to acidification.

Dr Hall-Spencer, a leader of the census’s CenSeam project focusing on seamounts, said that heavy “rockhopper” trawl nets that roll along the sea floor had ripped apart some reefs, including several at Rockall.

“Almost every coral reef and seamount I’ve been diving on has been severely damaged, particularly those off the west coasts of Scotland and Ireland,” he told the American Association for the Advancement of Science conference in San Diego.

“The main problem is bottom trawling. The gear has got stronger, so the trawler can risk getting closer to reefs. Sometimes they plough straight through. You see trenches ploughed through the sea bed that extend for kilometres. The coral is pulverised. The fish are gone because fish like to hide behind coral heads. It’s more like mining than farming — you’re removing a resource and not allowing it to renew itself.”

Corals that lie on seamount flanks, below the reach of nets, face a different threat: ocean acidification. As the level of carbon dioxide in the atmosphere rises, more gas becomes dissolved in the ocean, making it less alkaline. This reduces carbonate that corals use to build shells and other solid structures. The effect is especially marked in Arctic waters, as low temperatures amplify the effects.

“Many of these reefs look doomed,” Dr Hall-Spencer said, adding that pristine reefs as well as those damaged by trawling need protection. Shallow degraded areas should be included as “they’re all we’ll have left if and when acidification gets worse,” he said.

Recent trawling bans in Rockall Bank and last year’s Marine Act will help, but more reserves were needed to preserve areas such as Anton Dohrn, he said.

1.What is a tide? (What is a storm surge?)

2.How far ahead can the tide be predicted?

3.What causes tides?

4.If gravity is always pulling towards the moon, what causes the bulge on the opposite side of the earth?

5.Why are the tides not the same all round the coast of Britain?

6.How often do high tides occur?

7.Are there always two high tides a day?

8.What are spring tides and neap tides?

9.Why are they called spring and neap tides?

10.Where are the highest tides in the world?

11.Do the tides follow a repeated pattern?

12.When during a year can we expect to find the largest tides?

13.Do the planets have any affect on the tides?

14.How can tide tables be produced so accurately?

 What is a tide?

This is not as obvious as it may sound – it is not just the rise and fall of the water in our seas and oceans (tides are only one of the contributing factors in this rise and fall). A tide is the regular and predictable movement of water caused by astronomical phenomena – the way the earth, moon and sun move in relation to each other and the force of gravity. These are the values that you can see in tide tables. Movement of water caused by meteorological effects (for example winds and atmospheric pressure changes) are called surges. These are not easily predictable and require powerful computers and sophisticated software to predict just 36 hours in advance. These are the reasons why tide table predictions do not always agree with observations. POL develops storm surge models for flood forecasting that have been run at the Met Office since 1978. (A large positve storm surge can add a few metres to the predicted water level.) There is also wave movement which is purely wind generated and impossible to predict accurately. Therefore statistical values are used such as significant wave height which is the average of the highest 1/3 of waves.

 How far ahead can the tide be predicted?

Since the tide is caused by the astronomy of the earth-moon-sun system which is known very accurately and can be predicted well into the future, the tides can also be predicted well into the future. So if you want to plan your sailing club events for the next year, get in touch and (for a small fee) Applications Team will provide you with the tide table. When trying to predict well into the future, we have to take into account the rise in global sea level. The further into the future we try and predict, the more significant this effect can become.

 What causes tides?

Tides are caused by the effects of gravity in the earth-moon-sun system, and the movement of those three bodies within the system. If you imagine that the earth is completely covered in water, there are two bulges of water – one towards the moon and another on the opposite side (see question 4). The rise and fall in sea-level is caused by the earth rotating on its axis underneath these bulges of water. There are two tides a day because it passes under two bulges for each rotation (24 hours) (see question 7). This is called the lunar tide. Two bulges of water are also caused by the sun, called the solar tide – and these can either reinforce or partially cancel out the lunar tide to give spring and neap tides (see question 8).

 If gravity is always pulling towards the moon, what causes the bulge on the opposite side of the earth?

Most people think the moon rotates round the earth. In reality, the earth and the moon rotate about a common centre just inside the earth’s surface (indicated by the light blue dot on the diagram). At the centre of the earth the two forces acting: gravity towards the moon and a rotational force away from the moon are perfectly in balance. They have to be otherwise the earth and moon would not stay in this orbit.

 The ‘tide-generating’ force is the difference between these two forces. On the surface of the earth nearest the moon, gravity is greater than the rotational force, and so there is a net force towards the moon causing a bulge towards the moon. On the opposite side of the earth, gravity is less as it is further from the moon, so the rotational force is dominant. Hence there is a net force away from the moon. It is this that creates the second bulge away from the moon. On the surface of the earth, the horizontal tide generating forces are more important than the vertical forces in generating the tidal bulges.

Why are the tides not the same all round the coast of Britain?

You might expect that as Britain passes under the bulge of water, time of high water would be roughly the same for all points on the coast, but it isn’t. The problem is caused by the land that ‘gets in the way’ of the moving water. As the earth rotates, the water has to move to generate the high tides but because of the shape of coastlines and the variation in sea depth (bathymetry), there is a lag. Every location has a unique coastline and bathymetry – which gives each location its unique tidal pattern.

How often do high tides occur?

In UK waters, approximately every 12 hours 25 minutes. You may wonder why it is not exactly 12 hours, but you must remember that the moon is also orbiting around the earth. By the time a point on the earth’s surface has rotated from point x to point y (12 hours) the moon has also moved a small amount, so the earth has to rotate for an extra 25 minutes from point y to point z to be under the high water bulge.

 Are there always two high tides a day?

No. Although most places in Britain experience approximately two tides a day (semi-diurnal) there are some places which experience what is known as a double-high water (e.g. Southampton) or double-low water (e.g. Portland). This is caused by the shape of the coastline and the bathymetry (sea depth). The diagrams below show a typical tidal curve for three places round the UK coast.

In some parts of the world there is only one high and one low water each day (diurnal) – for example in Karumba, Australia. In other places, it varies between semi-diurnal and diurnal as in Musay-id in the Arabian Gulf.

 What are spring tides and neap tides?

When the earth, moon and sun are in line (during new and full moon), the bulges of water caused by the moon and sun occur in the same place on the earth’s surface. The lunar tide and the solar tide are reinforcing each other – which leads to higher than average high tides, and lower than average low tides. These are called spring tides. When the earth, moon and sun form a right angle (at 90 deg) the high water caused by the lunar tide coincides with the low water of the solar tide. This produces lower than average high waters and higher than average low waters which are called neap tides. They occur approximately 7 days after spring tides.

 Why are they called spring and neap tides?

Neap means low – so that is an easy one. Spring tides can be confusing because they have nothing to do with the season. It is not exactly known where the word ‘spring’ comes from in this context but there are two possible origins. One possible source is a Scandinavian word meaning to ‘leap up’. Another possibility is that it is related to the natural feature of a spring – which is a place where water wells up from the earth.

 Where are the highest tides in the world?

In Canada there has been some rivalry between Arctic Quebec and the Canadian Maritimes over who has the world’s highest ocean tides. The Canadian Hydrographic Service has declared a tie between the famous tides of the Bay of Fundy and those of Ungava Bay on the northern coast of Quebec. It has long been recognised that the tides at Burntcoat Head on the shore of Minas Basin, Bay of Fundy can in extreme reach a range of 17 metres. After 200 days of measurements at Leaf Basin in the southwest corner of Ungava Bay it is estimated that in the extreme the tides there could have a range of 16.8 metres. It is of course possible that points near Burntcoat Head or Leaf Basin, as yet unmeasured by tide gauges, could have slightly higher tides so lacking further data a dead heat has been declared.  The next highest tides are in the Bristol Channel where the extreme range at Avonmouth is just over 15 metres.

Do the tides follow a repeated pattern?

 No. There are similarities – for example every 18.6 years, we experience larger than average tides – but they never actually repeat. 12. When during a year can we expect to find the largest tides? A day or two after the full or new moon nearest to the equinoxes. The spring equinox is usually the 21st March, and the autumn equinox, the 23rd September. Some years have tides that are notably higher than other years. 1997 was a significant year, as will be the year 2015. For really favourable conditions – you will have to wait around until the year 3182. Even then, the tides may only be 1 or 2 cm higher than in 1997.

 Do the planets have any affect on the tides?

The tidal force generated by a planet is based on two things – the mass of the planet and its distance from the earth – and it is the latter of these that is far more significant. The nearest approach of Venus to earth is still more than 100 times further away than the moon. Hence the tidal force is approximately 0.000054 times that of the moon. The next most significant planet is Jupiter, where the tidal force is 0.000005 times that of the moon. So as you can see, the effect of the planets is negligible. Even if all the planets line up such that their effects are combined, the additional force would be minuscule. During 3rd May 2000, Mercury, Venus, Mars, Jupiter and Saturn lined up with the sun and moon. At the time a rumour circulated that the collective gravitational pull would initiate earthquakes, tidal waves and volcanic eruptions, something which never happened.

How can tide tables be produced so accurately?

There are many different steps involved in obtaining the final numbers that go into a tide table. Before a tidal prediction can be made for a port, a long sequence of tidal observations for that port are needed (called a time series). This time series will include all the astronomical effects and local coastline/depth effects (which make up the tide) as well as the weather induced effects called the surge (see question 1). As shown in questions 6 and 8, there are certain frequencies that are known to occur in the tide. Some of these are listed below: 12 hour (12:00:00.0) repeated pattern (cycle) due to the gravity of the sun. 12:25:14.164 cycle due to the gravity of the moon. 24:00 and 24:50:28.328 cycles caused by the differences in the two tidal bulges. 27.2122 day cycle caused by change in lunar declination (Moons angle to the Earth). 27.5546 day cycle caused by a regular change in the Earth-Moon distance. 29.5306 day cycle caused by the phases of the moon (see question 8). Each of these cycles is called a tidal harmonic constituent and as you can see, the frequencies of these is known very accurately. Therefore it is easy to find them in a sequence of observations using a method called tidal analysis. Once each constituent is identified, its size (amplitude) and time of ‘arrival’ (phase) is stored. These two values (known as a harmonic constant) are unique for every location. The amplitude and phase for each constituent combined with the fixed speed of that constituent allows us to predict its contribution to the overall tide forward or backward in time almost indefinitely. Adding up the effects of all the constituents at a given location lets us predict the overall tide at any time in the future or past. See the Applications Group Tidal Prediction Service. Most tide tables just list the time and height when the water is at a maximum and minimum level in each tidal cycle. This leads to approximately 2 high waters and 2 low waters every 24 hours and 50 minutes (or 4 tides a day on most days with 3 tides about every 7 or 8 days).

While you are bound to learn these signals when you begin scuba training it is often useful for beginners to make sure they remember what they are being taught, listed below is a list of hand signals commonly used underwater, in hopes that this will help some of the beginner scuba divers

There are many ways that you can communicate underwater when diving, but most of them have to do with Scuba diving hand signals. When you are underwater it is crucial that you are able to get in touch with your fellow divers to alert them of your situation. This is important not only to your own safety but to the safety of others as well. A few of the more common methods of underwater communication consist of: sign language, alphabet signals, diver signals, special signals for night diving, and even electronic communications devices can be used.

This article will introduce you to a few of the more common Scuba diving hand signals. It is not uncommon for Scuba diving hand signals, including sign language, to be taught even in dive school as this is the primary method that you will be using to communicate while underwater. Knowing at least the most basic Scuba diving hand signals is of utmost importance as you will need to know how to perform them in cases of emergency and even more importantly, in order to prevent the emergency from occurring in the first place.

Probably the most basic of the Scuba diving hand signals is the OK sign, which you probably know how to do already by simply placing the tips of your thumb and forefinger together.

To show that it is OK on the surface, you place the tips of all your fingers on the top of your head.

Next, there is the sign for ‘stop’ which is also common, you simply hold out your hand so that your palm is flat towards the person you are signaling.

In order to tell your diving partner to slow down, you signal to them by holding your hand out flat and moving it up and down slowly a few times.

Another important set of Scuba diving hand signals are those that deal with changing your depth. First of all, there is the signal for staying at the same depth which is achieved by holding out your hand flat and moving it left and right.

In order to signal to go up you simply hold out your fist and put your thumb up. To signal them to go down you do the opposite and put your thumb down.

There is the signal for ‘stay together’ which you perform by holding your two hands together with both index fingers out.

The most important signals to know are probably the distress signals, as explaining a problem underwater without voice communication can be very difficult and dangerous.

When experiencing a problem with your gear you can place your hand out palm flat, rotate the hand a bit and then point to the area of the problem.

The chart above shows more of the more common signals. The most important thing though is to ensure you and your buddy both know what the signals you may use mean.

A good SCUBA equipment configuration needs to carry through all of
your diving, from open water to cave in such a fashion that the addition
of items necessary for each dive does not in any way interfere with or
change the existing configuration. Diving with the same configuration allows
the same response to emergency at all times while reducing effective
task loading due to familiarity . In other words, it not only helps
solve problems, it prevents them.

Let’s start with the backup regulator ( not the “safe second” or
“octopus”, the BACKUP). The backup must be instantly accessible. We hang
it around the neck on surgical tubing or bungee which is held on by the
tie wrap that holds the mouthpiece to the regulator. It must be up close
to the neck in order to minimize the venturi effect on the reg, and to
provide a strap to hold that reg tightly in the mouth when necessary.
That reg must be a non air balanced, low performance reg. The
intermediate pressure of all regs should be held to a minimum to prevent
free flow and stress on the second stage and hoses. Since most regs feed
right to left, we initiate this regulator from the left post of the
manifold, with its hose short enough so as not to “flap in the breeze”
and wear out the swedge fitting. As with all hoses, we use a strain
relief. We do not use “upstream” valve regulators, regulators that get
water in them when scootering or in a current, or regs that require
custom hose fittings. We use regs that can be taken apart and cleared
underwater. We use regs that operate at low IP’s. We leave them loose so
that they can be changed underwater. For open water configuration assume
that all hoses are off of the one reg, rather than the manifold
doubles.

For manifolds we use the dual port style with a center shutoff for
redundancy and to be able to solve the most common failure mode: loss of
knob followed by a free flow, or roll-off followed by loss of the knob.
Manifolds should have barrel style o-rings, no face seals, and should be
adjustable. The ports would be 300 bar for more thread depth, and
should be straight facing ports, no angles which end up breaking off DIN
connections. Knobs should be spring loaded and soft with a metal insert
so they do not strip out – no metal knobs. Metal dents and will lock off
or on, and are hard to turn in a pinch. Burst ports would contain
higher working pressure plugs, and be changed often.

The primary second stage reg is then on the right post for redundancy
and ease of gas sharing. This is the long hose in any configuration. It
runs straight down behind the wing, under the light ( if a light is worn
- around the knife or tucked into the belt if not ) and back up the left
side , behind the neck and into the mouth. When not in use, as in
staging or deco, this reg is clipped of on the right chest d-ring using
a breakaway clip. While you always must be willing to donate the reg
that is in your mouth, switching to the long hose donation for
traveling is a must. You NEVER put the primary reg on the left post due
to the roll-off , break-off failure mode, the effective shortening of
the hose for sharing and comfort of routing, and the oblique angles
created in a traveling share that will restrict gas flow by being on
that post. Hoses float, and since the diver should always be in a supine
position for purposes of gas exchange and general good form, the hose
will be held against the body and stay in place. This treatment of the
hose solves several problems at once while not creating any and not
interfering with the rest of the rig. To make the long hose breath the
way you like it, adjust the intermediate pressure of the first stage,
but keep it as low as you can. Today, we all use helium for deep diving,
so the ease of breathing is greatly increased, allowing for lower
intermediate pressures.

The pressure gauge is from the left run straight down the left side to
the left side d-ring where it is clipped off. This has no boot , no
console , and no other clap trap on it. The hose should be short enough
to stay out of the slipstream and long enough to view when unclipped. It
is read on the fly with the left hand. The inflator from the wings runs
over the shoulder and through a small bungee attached with the left
chest d-ring. This keeps the inflator where it can be located instantly.
The inflator must be long enough that it can reach the mouth, the dry
suit inflation valve, and the nose for ease of operation with one hand
controlling all three maneuvers. It must be long enough that it can be
breathed by holding both buttons down at once (never “rebreathed”, only
breathed). The low pressure hose to it must come from the right post.
This then acts as a second backup or third regulator which can be used
if the left post knob either gets rolled off or rolled and broken off.
(The right knob can get broken off, but will roll “on”, so would be
broken off in the “on” position.) Also, you never want to discover you
have a roll-off by not being able to inflate – an invitation to further
problems. The inflator mechanism itself must not be air balanced or high
speed – it must be a slow inflator so that runaways are easier to deal
with. The diver must anticipate his inflation needs , part of good form
which is the hallmark of the safe diver.

Wings must not be too big or too small. A diver must start with a
balanced rig which gives him every chance to deal with emergencies. In
ocean or lake diving, steel tanks should never be used without a
drysuit. Double wings are an invitation to a disaster – do not use them.
Elastic wings are a disaster waiting to happen. They can not be operated
safely by mouth, they lose their gas if ruptured, they can not be
breathed like normal wings, and they cause more drag than normal wings.
For ocean, aluminum 80′s are the tank of choice. If more gas is needed,
take an aluminum stage, but don’t risk your life being over weighted at
the beginning of the dive. The buoyancy characteristics of aluminum,
especially when using helium , are such that a weight belt and or
canister light will provide the necessary ballast which can be dropped
in an emergency, making the rig only reasonably negative when full,
neutral when empty, but swimable by dropping the weight. In cave, steel
must be used with a drysuit and they must be negative enough to allow
the diver to stay down in a low on gas emergency. There is nothing worse
than being too light to stay off the ceiling while low on gas and then
struggling. For this reason, the rig must be balanced to a no gas
situation prior to cave use, and weighted accordingly.

The diver’s harness is rigged from one piece of webbing – no buckles
or disconnects or other failure points. One d-ring is on each chest, one
on the left side. The crotch strap is also one piece, and has a loop in
the front the the belt passes through. The belt buckle must be to the
right side so as not to get opened by the crotch strap. This strap is
necessary to hold the rig in place whether scootering or not. Any upward
pressure on the diaphragm crated by unstraped rigs increases the
breathing rate and discomfort of the diver markedly. The crotch strap
has a scooter d-ring just below this loop. We never use a quick
disconnect here. The knife is in an open sheath on the waist belt left
of the crotch strap, where it can be pulled like a gun. The backup
lights are attached to the two chest d-rings and held to the strap by a
bungee. This puts them under the shoulder and out of the way.

The light is worn to the right side on the waist belt, and is held on
either by the same buckle that fastens the waist belt, or by a second
buckle slipped on. The light head is held in the left hand , or clipped
of to the right chest d-ring when not in use or when changing stages .
There are no d-rings on the right side, but if a bottle is carried there
for some reason, a piece of bungee cord on the belt will suffice if the
bottle has the correct stage bottle buoyancy characteristics. The light
is part of your weight and balance, should never be on the butt, and is
under the shoulder where it is protected and out of the flow, and can be
conveniently operated or removed if necessary.

Stages should be aluminum 80′s. These swing equally from negative to
positive with air, less negative with gas, by the amount of the air or
gas carried. They are rigged with stainless steel bolt snaps, the size
of which is determined by whether or not your diving requires gloves,
and those are attached by a piece of 1/4″ line run under a hose clamp
halfway down the tank and tied to the neck. The upper clip should be
tight to the break of the neck, the lower clip should have plenty of
tail to work with. The bottle needs to be held close in the front and
lose in the back to prevent drag. There should NEVER be any metal to
metal connections of any part of your rig.

Stages need to be permanently marked as to their maximum operating
depth in three inch high letters placed horizontally in the orientation
of the tank on either side so that the diver can see what he is
breathing, and so can his buddy, no mater where the tank is. The stage
reg is rigged with a short pressure gauge which is bent back on itself
to face the diver and held in place by bungee cord at the first stage,
The reg hose must be the octopus length. The stage regs are always
parked on the bottle and the bottle turned off unless in use. Stages are
generally worn on the left side for streamlining, and because of the
position and balance of the rest of the gear and the other hoses so as
not to interfere with the operation of any other gear, as well as the
scooter , which is driven with the right hand, favoring the right side.

To deploy a stage, we look for the correct depth marking, we put the
reg around our neck, we then turn on the bottle , put the reg in our
mouth, and if we can breath, we are breathing the correct gas. It is
just that simple. No other convolutions are necessary, and would only add
to the chance for error.

Gauges and compasses are worn on the wrists. These must be situated
according to need. In the ocean, the compass is paramount, and needs to
be viewable and held in its correct orientation without interfering
with other activities – that means the left hand, away from the scooter.
The depth gauge and timer needs to be viewable all the time , so is on
the right hand. Fins straps and mask straps should be replaced with
springs and stretch material that will not rot and break on a dive.

To quote Bill Gavin regarding gear, a diver must “settle for nothing
less than perfection. Those who do will discover on their own the value
of such effort. Those who do not will never understand what the others
are talking about”. What we have presented here is called the “Doing It
Right” system, and is a platform that is integrated completely and
accommodates all contingencies and additions, but no phobias. Use it
accordingly with one caveat – “never break Rule Number One”, which is
“Don’t dive with ******s”. A “******” is somebody with an unsafe
attitude.

“Once you have learned to dive, you have the ability to enter a strange and wonderful region of our planet.”

Sound tempting? I thought it did. I was headed eventually for Malta, an island renowned for its time-share apartments and residents disproportionately clumped towards the wintry years. Less well known is that this ancient enclave of the Knights Hospitaller is also, owing to the superb visibility of its waters and the centuries of shipwrecks littering the seabed, one of the best places in the world to dive.

I began my diving adventure in the less alluring surrounds of the Shell Centre in London, a great warren of a place providing all sorts of amenities to the oil company’s many thousands of workers, including a rather plum, near-Olympic-sized swimming pool. Shell lends the facility to local dive clubs for training; you will probably find yourself in somewhere similarly chlorine-scented should you yourself decide to take the plunge.

I would make an easy analogy between scuba divers and elephant seals and say that both look elegant within the water but rather absurd outside it, except that I managed to look comically ungainly on both sides of the H2O divide. “B-A-R: buoyancy, air, releases”… you quickly learn the safety checklist to go through with your dive “buddy” – the bit of Americanese meaning your essential companion on every descent – and then it’s, plop!, into the pool.

Cue, on my part, no displays of balletic sub-aquatic grace but, rather, a bubbly shriek of something like: “What’s this metallic monster on my back, dragging me” – clang! – “down to the bottom?”

That buoyancy is the key, you see. “Neutral buoyancy is happiness,” says the sub-aqua club manual, going all Zen-like again. You gain this ideal state by delicately adjusting the flow of air in and out of your wetsuit.

© Malta Tourism Authority, Into the depths… Malta

Gain it – slowly. It takes years to attain that gorgeous mid-water float that we jealously watched our instructors assume naturally.

The body, however, cries out for control in any environment and, within a day or two, I had developed a surer reach for the triggers and valves that controlled air movement on the wetsuit. I could even manage a submerged somersault or two, albeit still plummeting occasionally to the tiled ocean floor or shooting helplessly to the surface.

There’s theory, too, on the introductory diving course, and quite a lot of it for people who would prefer to hurry up and swim with the fishes. The focus here is the bends, otherwise known as decompression sickness.

You soon learn, when you begin to dive, that humans weren’t really meant to. Descend any deeper than 20 metres and you will have to stagger your ascent to allow all the nitrogen you have absorbed to dissipate. Fail to do so and you risk symptoms ranging from a not unpleasant sounding intoxication to crippling pain (causing you to “bend” to avoid the most agonising position) and death. That’s why divers have to learn to read fairly simple mathematical tables to know how long they can safely remain at a given depth.

Yes, it does sound a little frightening, which is why novice divers, unless they plunge disastrously like a big fat stone, are kept nicely above the 20-metre mark. My first dive in Malta – slightly reluctant as I was to leave the still toasty October sun to slip beneath the surface of the sea – was on a first world war troop carrier that had lasted until the next global conflagration only to be sunk by the Luftwaffe.

We slipped into the water off a ruined 19th-century quarantine station, an eeire place I imagined to be patrolled by tubercular ghosts. The X-lighter (as this kind of troop ship was called) was a few metres off the shore and a timid six metres down. Or apparently it was: storms had churned up the sea – Malta was not living up to its crystalline reputation – and, besides, the water had thoroughly claimed the stuck vessel and camouflaged it with a fur of brownish gunk that, to me, made it look thoroughly abstract.

As for that otherworldly quality the diving club manual had promised, well, the oh-so-easy flow of the canned gas into my lungs felt as if I had somehow brought the above-surface world down below with me.

My second dive revealed more recognisable bounty: the Lady Davina, a medium-sized craft sunk at her mooring just a year or two before – as if, one day, she had decided she didn’t want to go on any more and had just drowned herself where she was tethered. We glided in, raven-like, over the top of the engine room, entering the wheelhouse through the the galley. Rolled up charts still lay on the shelves, poignantly useless now; the fridge was still full of beer. On the seabed around the wreck lay plates stamped with sadly pompous Royal Navy insignia from an earlier age.

Only on my final day was I treated to that famous Maltese aquatic clarity. We dove off the harbour wall next to a white watchtower with a whimsical-looking spiral staircase. Now that the distractions of water-borne haze and gunk-covered manmade things were gone, the underwater world swiftly felt cathedral-like. We wended our way through a natural rock tunnel, the water around us so transparent I kept, with a shock, having to remind myself what was supporting me.

There was no route on this dive; your fins somehow set the direction. At one point David, my instructor, somewhat meanly, I thought, plucked an octopus from its hiding place before letting it go again. It flared enormously and then emitted a great, curlicued cloud of ink, as if in some furious artistic gesture.

A little later David found two rocks and started hammering them together. His purpose was soon clear: the sound attracted beautiful, vibrantly coloured fish, who approached bobbing their sleek, pointed snouts as if in time to the rhythm.

As I hauled myself from the sea up a rocky little cove to the carpark I realised I had entered that promised other world without noticing. Looking around me I saw that what looked like the whole of Malta’s diving population, hauling on wetsuits, checking their tanks, were soon to enter in turn. I wondered whether you got so used to floating neutrally in that other, aqueous world that you never really wanted to leave it.

Wetsuits

As we are aware, diving wetsuits are made of neoprene that acts like a sponge adding buoyancy without absorbing water. The insulation comes from these neoprene cells that contain a gas allowing for the separated bubbles to trap heat and protect. The thicker the suit, the more insulation they provide in accordance with the depth you plan on diving.

Dry Suits

Just as in the past, when you have to leave playtime as soon the real fun starts, the cold makes its presence known as soon as you start enjoying the water. A scuba diving dry suit allows one not only to stay in the water for longer but also to experience rarer dive sites – which are not surprisingly more often the colder ones.

The loose fitting dry suit provides a ‘double protection’ insulating with a layer of air. The air that fills the suit comes from your tank via an outlet specially designed for this purpose. A release valve provides the outlet and the presence of air inside your suit therefore requires more attention to buoyancy than a wet, tight fitting one. The operating process requires a short course to master the various technicalities involved.

Dry suits seal at the wrist and neck with the added feature of a zipper that keeps the water out and contain special inner garments that form part of the crux of the purpose of the suit itself. These are designed in accordance with how deep you want to dive in a similar manner that the millimeter thickness of a wetsuit provides the correct insulation against water temperatures and depths.

Hoods

Since it’s a well known fact that over 70% of your body heat ‘escapes’ through your head its advised to consider a hood for diving in water temperatures below 70 degrees F.

There are a few variations among which the bibbed hood provides a good amount of insulation as it extends in circumference over the upper part of the chest and is tucked into the wet or dry suit preventing water leaking in through the neck area.

Colder climates will require a suit with a hood as a permanent fixture. Ensure that the fit is snug and comfortable, a tight hood can have detrimental consequences to blood circulation.

Gloves

Protection from the elements is a key when it comes to diving gloves. Your hands may become soft from extended exposure to the water and cut or scraped easily. Cold water will numb your hands and make it hard for you to operate your equipment.

Boots

Protection against cuts and abrasions as well as heat loss will be prevented by acquiring a pair of diving boots. They also allow for more effective control with water propulsion using your fins.

Alternate air sources

Commonly referred to as the octopus or ‘octo’, the second stage allows you to provide an alternate air source for yourself or your buddy in case of an emergency.

Thermometer

Not an essential accessory, but it does come in handy when monitoring your temperature in accordance with depth and time in the water.

Compass

While underwater it is easy to loose your sense of direction, specifically in bad visibility or unfamiliar surroundings. Using your compass as reference will assist in many a sticky situation.

Submersible Pressure Gauge or SPG

Your SPG is the essential air consumption monitor. Checking your SPG regularly allows you to gauge your average air consumption during a dive so you can monitor temperance. In this way you can log how much air you use on the dive and how much to consciously consume in order to practically maximize your consumption on the next.

Weights

The purpose of weights in diving is not to make you sink, but to ensure that you maintain buoyant with all the floatation and warmth-inducing devices required for the dive. Weight belts are available as a separate fixture or integrated into the BCD or suit.

Weights need to be arranged in an even distribution around the body in order to ensure that you maintain your buoyancy as effortlessly as possible without needing to compensate for a lopsided physical disturbance in the process. A quick test is whether you float at eye level when you are in the water.

The belts all come with a quick release system which is their most functional and essential feature in the event of an emergency.

Diving equipment maintenance is an essential step to keeping your gear in good working order that should not be ignored. You will find that when taken care of it will not only last longer but will be much safer for you to use. Most pieces of gear are made out of plastic, rubber, and certain metal parts that can become oxidized and decay. There are many different things in the water that can cause damage such as salt, dirt, dust, and heat not to mention the ultraviolet rays and ozone.

As a diver it is your responsibility to make sure that your gear always stays in the best possible condition. The first piece of equipment that we will look at for diving equipment maintenance is the regulator. Once you have finished using it immediately soak it in a bucket of clean, fresh water for about an hour. It is also a good idea during this time to work the buttons, levers, and knobs to loosen up any pollutants that could cause them to stick later. Next you can rinse off the first and second stages to loosen up any dirt that may be inside. When soaking your regulator you want to make sure that no water gets into the first stage, so leave it connected to the pressurized tank.

The tanks must also receive the necessary diving equipment maintenance in order to keep them in good working order. Make sure that you rinse out the SCUBA tank cylinders thoroughly after each use after removing the tank boot and drying out the cylinder. Also be sure to open the valve for a short period of time in order to release any moisture that could be in the valve’s opening. Be sure to keep your air cylinders inspected regularly and make sure there is no corrosion or heavy wear on the outside of the tank. When storing, tanks should be pressurized to 25 psi.

Proper diving equipment maintenance also means taking special care of your diving masks. They typically come with protective cases for travel, so make sure you also use them. Before use, also make sure that the mask fits snugly and make sure that there is no wear and tear that could lead to performance problems later. Do your best to keep your mask out of the direct sunlight, especially for prolonged periods of time as this can lead to bleaching and drying. In addition, never place the mask face down as this could scratch the surface.

Finally, be sure to keep your wetsuit, boots, and gloves in good condition by soaking them in fresh water and rinsing them off thoroughly with each use. When you take part in the necessary diving equipment maintenance you will find that your gear will be safer and will last much longer.

One area in particular which demands very serious consideration by every diver, is that of which regulator to donate in an Out Of Gas (OOG) scenario – Different schools teach different things for better or for worse, which has resulted in a far from consistent approach and you never really know what is going to happen even if you follow the traditional “buddy check”…you wouldn’t be the first person to face a panicked out of gas diver underwater who you have never seen before in your life, particularly on some of the more regularly dived sites where six or more dive boats can congregate at a time.

So what do you do in this situation? Basically there are two schools of thought – Give the Primary Regulator in your mouth OR Give the Back-up Regulator which you bought specially just in case. To compare the two:

Giving the backup regulator

The theory is that you don’t want the “Rescuer” to remove his Regulator when he is going to have enough to deal with, managing an OOG Diver, so instead you give the so-called “octopus”.

        Advantages

• Rescuer doesn’t have to remove his regulator
• Appropriate to raw trainees who are unfamiliar with very basic skills

        Disadvantages

• The spare regulator may not be immediately to hand – the rescuer may have to take time to find it, particularly if it has become dislodged or is stored in a less than obvious location delaying donation to the OOG Diver
• Spare regulators are stored in different locations, so the OOG diver never really knows where it is coming from particularly in a stressful situation when the earlier buddy check may be forgotten
• No surety that it will work – it may have unknowingly become blocked with silt etc if poorly located/not recently checked.

Giving primary regulator

The basic concept is that you want to get a working gas supply to the OOG Diver as quickly as possible by giving the regulator you are breathing – the first breath being the most important one.

        Adantages

• It keeps it simple. If the regulator in the mouth is always donated then the OOG diver always knows where it is coming from.
• OOG diver and rescuer always knows where to find the regulator quickly and easily.
• OOG diver can see it working as he approaches and has confidence that it will deliver gas promptly.
• The first breath is the most important one to alleviate any stress and panic so it must work.
• The rescuer is the best placed person to retrieve the backup (it’s his gear so he should know where it is!)
• Rescuer needs to be prepared to give the regulator in the mouth – a panicking diver may just take it anyway!
• You want to give the best performing regulator, which is generally the one being breathed.

        Disadvantages

• Rescuer may be left with a non-working regulator, but as the least stressed diver he is the best placed to find that the first breath doesn’t work and fix it or resort to buddy breathing.
• Rescuer must be well versed in regulator removal and replacement – as a basic scuba skill, this should not be an issue

In theory an OOG diver should always signal that he needs gas and then be promptly handed a regulator. Unfortunately all too often a distraction, poor buddy skills or a lack of regular training can mean that signals aren’t seen or are met with a blank look.

Whichever way you dive – be prepared to lose the regulator in your mouth, whether by choice, if it should be knocked out or even grabbed by an over-enthusiastic OOG diver when his survival instinct kicks in – experience has shown that a panicked or OOG diver will frequently take the most easily obtainable supply of gas, even when that is the one in your mouth, particularly if there is any kind of delay. He is probably already out of breath from swimming to you and you can’t always rely on the luxury of a hand signal and them just sitting there waiting for you to pass what he needs to survive! If only life were like all those pool sessions…

Irrespective of which of the above two schools you fall into, it is essential that any spare gas supply/regulator to be breathed (including the back-up/octopus):

• Be easily found and retrieved
• Cannot be at risk of being silted up/dragged in the dirt etc
• Cannot purge away un-noticed
• Be checked regularly both before and during the dive

Afterall, you may be the one who is deprived if it isn’t easily to hand, planned or not! Stuffing the regulator in a BCD pocket is not the way to go, whichever way you look at it.

Increasingly back-up regulators are bungied just beneath the chin, this is an easy and cheap option worthy of consideration.

Something which is worth consideringin OOG scenarios is the use of torch signals to indicate a problem at an earlier stage, particularly the newer powerful HID type lights. Wildly flashing it from side to side will indicate a problem and your buddy can then be ready and swimming towards you at a much earlier stage than would otherwise be the case, regulator in hand. Of course you shouldn’t be too far from each other anyway…although the time and effort to swim with all that equipment is all too easily under-estimated!

Ideally there would be a consistent approach to this issue across the entire sport, but unfortunately that is very unlikely to happen any time soon. So in the mean time make an informed decision and be prepared in case someone just grabs the one out of your mouth one day whilst you are focussing on that pretty little nudibranch…

The mammal, which experts think weighed about 20 tonnes, was found at Beadnell Bay near Seahouses on Monday.

The British Divers Marine Life Rescue (BDMLR) said the whale was alive for a time, but could not be saved as the tide was going out.

The organisation said it was likely the whale had suffered dehydration after losing its way.

Richard Ilderton, of the BDMLR, said the whale was too heavy to have been lifted back into the water.

He said: “This animal is definitely not local and not of these waters.

“It probably became unwell and took a wrong turn.”

Sperm whales are the deepest diving mammal and the largest toothed of all whales.

They can grow up to 18m (59ft) in length and weigh up to 50 tonnes.

The mammals are found in all oceans, except the Arctic and feed on squid and other large deep-water fish.

Post from BBC news site