The importance of fins in scuba diving cannot be stressed
enough. A diver wearing full gear, including a wet suit, is unsafe in the
water without fins. Trying to swim with just your arms is very strenuous
and, as swimmers experience in a pool when they try to swim a length using
the legs only, propulsion without moving the arms is very, very difficult.
The author once saved a diver that entered the surf with his fins under his
arms. A wave knocked the diver over, the fins were lost, and he floundered
in the sea and almost drown before being pulled to shore. The ability to
comfortably move about while diving is made possible by the use of
fins!
The proper name is, "fins." Flippers are found on pinball
machines and in the list of names for dolphins.
Basically there are two types of fins: Full-foot and
adjustable. Full-foot fins are worn on bare feet and they cover the entire
bottom of the foot. Adjustable fins have a strap in the back that can used
to tighten the fin on the foot. Adjustable fins are usually worn over wet
suit boots. Most divers wear the adjustable fin with the wet suit boot even
in warm water. The fin and pocket is usually larger, and because of the
boots are more comfortable on the foot. Full-foot fins must be fitted properly
and are not as forgiving to the foot if they are not. A full-foot fin that
is too loose can result in painful blisters. Also, since there is no protective
boot, any rubbing points on the fin can be annoying. However, full-foot fins
cost about 1/5 of what it would cost to buy the adjustable ones with boots.
However, if you do have a pair of full-foot fins that are too large, wearing
cut-off socks might prevent problems.
There is always the question of how and when to
put the fins on for diving. The answers really depend on the diving situation.
In all cases, be sure there is some air in the BC prior to entering
the water! The following may help to clarify the issue:
-
Boat Diving: If you are going to enter the water from the stern of the vessel,
keep the fins in your hands until you have gotten to the stern, sit down,
and put them on. A diver should not be walking on a boat with fins on their
feet unless there is plenty of room to avoid other divers. If you are going
to enter the water from the gunnel (side) of the vessel, donn everything,
get up on the gunnel, put your gauges between your legs so there is
no issue with the cleat, and then do backward roll.
-
Beach Diving with Surf: Carry the fins to the edge of the water with all
the gear on except for the gloves and the fins. Using your buddy for support,
donn the fins. Donn the gloves and walk into the water backwards. Try to
time the entry to go between the breaking waves.
-
Beach Diving with Calm Water and No Underwater Drop-offs: Carry the fins
and gloves into the water to water that is waist deep. If the water is cold
put on the gloves before the fins, otherwise do it in reverse. Get your leg
into the "figure 4" position and the fin strap below the fin. Put the fin
on the foot and pull the strap up around the heel and into position. Do the
same for the other foot.
-
Beach Diving with Calm Water and an Unknown Bottom: DO NOT GO IN THE WATER
WITHOUT THE FINS ON! Follow the directions (above) for Surf Beach Diving.
When the fin is on the foot and it is necessary to move
from one place to another walking backward is the easiest. Trying to walk
forward is difficult because of the length of the blade. If the diver is
going a long distance, or is in crowded quarters, it would be better to move
without the fins on the feet.
Kicking underwater with fins on requires proper technique.
The power of the fin comes from the downstroke almost completely. High pressure
is created on the down side of the fin because of the increased number of
water molecules that are ecountered and have to be moved aside. The up side
of the fin would have a lower pressure. The high pressure pushes the diver
forward. Incidentally, the molecules that are pushed away from the downside
of the fin is called drag. The recovery of the leg to the up position
provides little thrust. To get the most power out of the kick, the knees
should be bent very slightly so that most of the power comes from the muscles
in the rear end. When one kicks from the knees it is called a "bicycle kick."
It produces very little forward motion, exhausts the diver, and looks stupid.
The kick should be from the hip and the legs should move a great distance
up and down. It should be relaxing and leisurely, unless you are being chased
by a shark.
When you buy fins be sure to try them on prior to the
purchase. If you are going to by fins through the mail, over the Internet,
etc. make sure you know the exact size and brand prior to doing so. Fins
are like shoes. If they don't fit properly they can damage the foot. And,
to get the size and the brand you have to try a pair on.
When not being used fins should be stored properly after
rinsing with fresh water. Do not store them in a hot place, resting on the
blade, or with objects on them. Thermoplastic fins may permanently change
their shape.
Check the straps and buckles prior to each dive. Remember,
a diver scuba diving without one or both fins is in a dangerous situation!
