Monofins and flippers

The film "Splash".

In many stories mermaids seem to have magical powers:  When they swim in the sea they have a fish tail, but when they come ashore they magically grow legs and walk around just like a normal woman. Back into the water they grow a fish tail again.  It all sounds like a fairy story.  Surprisingly, there is a logical explanation for this, in the modern monofin.

 

Monofins began to be developed in 1972, by a Ukrainian swimming club, and have been used for finswimming competitions ever since.  It probably started off as a fun event where competitors attached artificial fish tails to their feet, but the power and speed produced by these monofins was so impressive, it became a regular event, and was adopted by other swimming clubs.   They quickly encountered a problem, because the sheer power of the monofin created such a large bow-wave in the swimmer’s face that they couldn’t breathe.  To get around this, they had to use a snorkel to breathe in air, which means the monofin is better suited to swimming underwater.

Swimmer showing the power of the monofin

 
 Freedivers adopted it because they found the monofin gave them speed and power swimming underwater without their using too much effort.  This is very important to freedivers because the more effort they use, the quicker they use up the air in their lungs, forcing them to come to the surface sooner than they would like.

 So is this the explanation of why mermaids in the past were able to magically grow fish tails in the water and grow legs while on land?  Did that they put on monofins when they went into the water and take them off again when they came back to land?  Unfortunately this is not supported by observations of the Haenyo and Ama divers of Korea and Japan.  Until very recently they have never used swimming aids like monofins or flippers.   But a monofin could solve a big problem all working breath-holding divers have.

 Ama diving for shellfish in shallow water

Breath-holding divers in deep water cannot carry anything but the lightest load from the sea floor to the surface.   This is not a problem in shallow water because breath-holding divers can quickly dive down, pick up a handful of shellfish and come to the surface in less than a minute.  With repetitive dives they can quickly acquire a lot of food.  However because marine food is easy available in the shallows, they can become quickly overfished, so divers are forced to move further and further out to sea and greater depths.   At a depth of about 10 meters a breath-holding working diver will have to stay underwater for at least 3 minutes.   She can’t keep on diving continually as is the case in shallow water, as it will create medical problems, so she would need to take breaks between dives.   This  limits the amount of food a breath-holding diver can foraged underwater at these greater depths. 
The Japanese solution to this problem is for the Ama diver to tie a rope around her waist, and tuck into in a heavy iron bar.  This bar serves two purposes.

Iron bar of Ama Diver

 It is used to dig away shellfish that are glued to rocks, and acts as a weight so the diver can sink to the sea floor more quickly.  On the sea floor she quickly collects as much marine food as she can find, and puts it in a string bag, then tugs on the rope.  Men in the boat above pull her to the surface.  This strategy means she is not limited by the weight of her catch in each dive.

As far as we know, mermaids in Europe didn’t do this.  There are no stories of mermaids jumping off boats with a rope around their waist and then being hauled up by men.  But there are a many stories of mermaids with one or two fish tails which might have been monofins or flippers.  There are also off course stories of mermaids without any fish tails but as in shallow waters monofins and flippers wouldn’t be an advantage, mermaids would only use them in deeper water. 
The big advantage of a monfin in deep water, is that the mermaid can use it’s power to drive herself quickly to the bottom of the sea, without using weights to make her sink faster.  When she has collected what marine food she can find, she can then use the monofin to drive herself to the surface.  The same would be true for flippers and it is of interesting that modern Ama divers have started to use flippers in recent times.

The official history of swimming aids is that the first person to propose flippers or swimming fins was Leonardo Da Vinci, followed by Giovanni Alphonso Borelli in the 17^th century.   But the man credited with making and using them was the inventor and politician Benjamin Franklin.  As a young man he made flippers out of two thin pieces of wood, in the shape of artist palettes.  They never caught on, and it wasn’t until the 1930s when inventors started to make flippers out of rubber, that they were widely used.  Later on the monofin was invented by the Ukrainians. 
So could mermaids have used swimming aids like monofins and flippers in the past?  It’s possible since we know  that the Polynesians once had flippers which they made out of palm leaves. In the 20th century various inventors began making flippers or swim fins out of vulcanized rubber. One of these inventors was the American Owen Churchill.  The idea came to him while on a trip to Tahiti in the mid-1930’s, where he observed a group of natives on the beach weaving small mats from palm fronds and dipping them into a tub of hot tar. When the tar had cooled and hardened, they would tie these mats to their feet, then enter the ocean to swim and dive underwater.  How long the Polynesians have been doing this, is unknown.  It could have been for hundreds or even thousands of years.

Polynesian surfers, (19th century drawing)

People in the past must have realised that one of the reasons why fish and dolphins are so fast in the water, is because of their tails.  So someone could have tried to make an artificial fish tail.  Perhaps at first, like Benjamin Franklin’s flippers, they were not very effective, but over time they would evolve and the design would improve.  The first monofins built were very crude, some made of two titanium rods connected by a sail cloth, but they quickly evolved to the monofins we have today.   Perhaps some of the monofins in the past might have been made of thin branches, cloth or leather.  Wood would be even better.

Modern monofins are made of fibreglass and carbon fibre.  These are very stiff materials but the monofins are made to bend by making the fibreglass or carbon fibre very thin.  The same is true of wood.  It is also a stiff material but can be made very bendy if it’s thin enough.  Some people might object that wood would be too weak to make a monofin, but in the past people would have used split wood which is stronger than the sawn wood we use today.

To prevent splitting, the wooden mono fin can be made in a Vee shape as shown in the drawing.

Some modern monofins resemble an aeroplane wing.  This is a very simple design, and means a monofin could be made from a plank of wood.  Unfortunately there are no stories, of mermaids with planks of wood attached to their feet!
It’s conceivable that sailors and fishermen seeing mermaids with monofins and flippers on their feet would report them as women with a fish tail or two fish tails.  They might be perfectly aware that these tails are artificial, but they wouldn't have words like monofin, flippers or swimfins, to describe them and people, who never saw them, would take them at their word and think they are women with actual fish tails.

When artists are told to draw them, they would draw, paint or sculpt them as women with a fish tail, or two fish tails, as well.

There are other stories from the past where mermaids are decribed as having a serpent’s tail or a very long fish tail.  This can also be explained by flippers and monofins.  The original rubber flippers of the 1930s were short and stubby but now they have evolved to be very long and flexible.  It seems that freedivers prefer these very long flippers.

 The same could have been true in the past.  Over time, people may have realized that long flexible flippers were more efficient that short ones.  As previously mentioned wood can be made very flexible if it’s thin enough and the degree of flexibility can be controlled by the thinness of the wood.  Long, wooden flippers could have been constructed.

Any sailor seeing these very long flippers would describe them as looking like a serpent’s tail or tails, and land people would again interpreted this as being an actual serpent’s tail.  Monofins could have also been made to be long and thin, because if this design is efficient for flippers it might also be true for them.

 Another possibility is that people in the past may have realise that a monofin could have more power and leverage if put on the end of a flexible pole, making the tail look a lot longer and giving it the whip action you see when dolphins flick their tails.  This is shown in the next drawing.

 

 Selkie

In Northern Scotland, the Orkney Islands and the Shetland islands there are myths about the Seal people or Selkie, who are, seals when they are in the water and human being when they come on land.  In other myths they say that mermaids put on animal skins when they go in the water.  Maybe it’s not a magical story after all.  It could just mermaids who are wearing seal skins, perhaps like the modern wet-suits, we see on modern Haenyo divers.

 Haenyo divers

Another possibility reflects a modern-day practice, where women encase their legs in a bag, tie it at the waist and have a monofin at the bottom of the bag.  This make them look like a classical mermaid.  Mermaids in the past, may have done the same with seal skins.

Two dead seals

They could cut off the head of a seal, remove all the fresh and bone without damaging the skin and use the seal skin as a primitive wet-suit.  It is doubtful if the seal’s feet could be used as a monofin, but perhaps a wooden one could be attached to them.  People seeing this costume would easily believe they are seeing a woman who is half woman and half seal.
An added benefit from the seal costume, is that it would protect the feet from frostbite, It would also allow mermen to dive in cold waters.  We previously mention the problem men have swimming in cold water, but a sort of wet-suit seal skin over the sex-organs, would afford some protection from the elements.
The next video will be about the siren call and why we have so many stories of sailors that find the singing of mermaids so irresistible, that they will sail towards them and crash their ship onto rocks.