by Stephen Bryen*
The British learned about it from a spy working in a New York Congressman’s office who informed the British governor of New York by sending a coded message. The message said that the colonists would launch a new weapon in Boston Harbor where the British fleet was then based in 1775. Thus warned the British tried to take precautions, but at that point nothing happened.
The secret weapon was a near-underwater vehicle equipped with a drill screw and a barrel bomb. The purpose of the screw was to drill a hole into the submerged side of a British warship. Then, using a timing mechanism designed by a New Haven watchmaker named Isaac Doolitle, a flint-lock trigger would set off gunpowder packed into a barrel. On September 6, 1776 the semi-submersible, dubbed The Turtle, was taken out into New York harbor near Governor’s island where the British fleet flagship HMS Eagle was moored. The drill could not penetrate the Eagle’s hull because, while it was wooden, it was covered with copper sheathing. When British soldiers caught on to the attempt to attack the Eagle, the barrel bomb, which was then called a Torpedo, was released and floated down-river where it exploded. The Turtle managed to escape.
The Turtle, designed by Yale student David Bushnell, was the first submersible system used in combat. That it failed was rather an intelligence failure more than anything else, since the copper sheathing of the Eagle and other British vessels had only recently been introduced. While the presence of copper sheathing was new for the British fleet, other historians claim that the HMS Eagle didn’t have it, but that the crewman manning the Turtle either hit an iron bolt or some other iron plate and not the copper.
Bushnell was a creative inventor. While he used the Turtle to go after the British flagship, he went on to set off a floating keg mine aside the HMS Cerberus in 1777. It killed four sailors but the ship survived until it was captured by the French in 1778 and burned. Bushnell’s adventures with floating keg bombs not only earned him the admiration of many colonists, but a popular ditty was written to cheer the troops and encourage the public to keep the revolutionary faith. (Listen to the song Battle of the Kegs here )
The Turtle was one of a number of early submarines built in the United States and Europe from the mid-1600’s until the latter part of the 19th century. All of them followed an important principal learned from fish: the ability to raise and lower themselves in water by adjusting ballast.
A fish does this by use of its bladder, called a swim bladder. Not all fish have swim bladders, but those that do can use them to raise or lower themselves in water.
The swim bladder has had value to humans for many centuries.** Today the collagen derived from the fish bladder from cooking is used to produce Isinglass that is used to clarify beer (and making Isinglass-cleared beers problematic for vegetarians). More recently Isinglass is being used to treat wounds without the need for additional dressing. Thus an ancient material is playing a new role in the rapid treatment of wounded soldiers.
The same material was used centuries back for condoms. It was also used in court plaster because of its glue like character. But most importantly it was used to produce much strong weapons in ancient times.
The bow and arrow is a very ancient weapon, known for more than 10,000 years. It was essential for hunting as well as for war. But, as archers surely knew, there were problems that plagued this weapon. The bow was subject to breakage, either snapping or cracking which made it worthless. So too was the bow string, made of animal gut, likely to fail at the most inopportune moment. Fighting range was limited and accuracy was poor because of the shock to the structure when the bow string was pulled back hard and released. The “snap” was moderated by transversal forces on the string, creating twist in the released arrow that would throw it off course unless compensated by an experienced archer.
The invention of the composite bow improved archery and was a key to giving the chariot archers greater range, better accuracy, and more killing power since an arrow launched from a composite bow at a target could penetrate a hard target up to three inches.
There is debate about the origin of the composite bow; whether it initially was a Sumerian or Akkadian invention, or whether it was Canaanite. It was surely a vital weapon for the Hyksos who, along with their chariots, overpowered Egypt’s military forces around 1650 BC.
The composite bow is made from wood, horn sinew and fish bladder. The secret is the fish bladder which, when prepared and cooked down, forms durable glue, the epoxy of the ancient war fighter.
The bladder itself is primarily a collagen material, and the best fish bladders for the collagen glue are found in carp, sturgeon, catfish and cod.
The advantage of glue based on the fish bladder is that it is stronger and can stand more torsion effects than glue made from beef sinew scrapings either from an animal’s gut or from the surface of leather. We don’t know whether bow makers in the Middle East produced their own Isinglass, or if it was imported. Certainly, for chariot and composite bow making, many of the woods needed to manufacture the bow had to be imported. The production of a composite bow was a slow process. Wealthy property owners paid by tribal chiefs managed bow and arrow production and used slave labor to do the manufacturing. Some believe that the production of a good composite bow could take a year’s work. This suggests there were many hands involved in bow and arrow making and that production was a vital part of a well organized and disciplined community that was hierarchically organized. The system provided everything for the foot soldier; uniforms, food, weapons, transportation and medical care.
If fish bladders could be used to help produce more accurate, more lethal and longer range bows for warfare, other parts of the fish can also serve in peace and war.
At the Tokyo Institute of Technology Junzo Tanaka and Toshiyuki Ikoma are using collagen derived from fish scales to help elderly people regenerate bones that have been weakened by tumors. They chose Tilapia for their experimentation and found that bone regeneration can be accomplished in as little as three months using this “new” fish technology.
At the Massachusetts Institute of Technology and the Technion in Israel fish scales are the inspiration for a new generation of body armor. The Technion team has “created a composite material that consists of stiff, overlapping outer ‘scales,’ combined with a layer of soft and flexible material underneath. The addition of the scales boosts the softer material’s penetration resistance by a factor of 40, while reducing its flexibility by a factor of only five.”
Of course Samurai warriors’ armor also took advantage of the design of fish scales in the form of overlapping curved enameled iron plates sewn into their armor garments. So the latest from MIT and the Technion inventions owe a lot not only to the fish, but also to the skilled artisans in Japan in the Sengoku period who fashioned the Samurai’s protective gear.
While we all know that fish are an important source of protein and nutrients for mankind, the fish is also an inspiration for inventors and for innovations that stretch over countless centuries, uniting our past with our future.
*part of this essay is derived from my forthcoming book, Technology Security and National Power: Winners and Losers (Transaction Press: 2016)
**fish bladders are also tasty and used in Chinese and Asian cooking where they are known as Fish Maws. For a recipe click here.