Saturday, 8 March 2014

The Turtle (Submersible)


I wanted to create something one of the kind, and this vessel was very appealing to me.
Also it was full of mechanical parts for Technic, but it also had very challenging egg shape ideal for ModelTeam and one person inside it operated all of the functions.


Real one:
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The Turtle (also called the American Turtle) was the world's first submersible with a documented record of use in combat.
It was built in Old Saybrook, Connecticut in 1775 by American Patriot David Bushnell as a means of attaching explosive charges to ships in a harbor.
Bushnell designed it for use against British Royal Navy vessels occupying North American harbors during the American Revolutionary War.
Connecticut Governor Jonathan Trumbull recommended the invention to George Washington; although the commander-in-chief had doubts, he provided funds and support for the development and testing of the machine.
Several attempts were made using the Turtle to affix explosives to the undersides of British warships in New York Harbor in 1776. All failed, and her transport ship was sunk later that year by the British with the submarine aboard.
Bushnell claimed eventually to have recovered the machine, but its final fate is unknown.
Modern functional replicas of the Turtle have been constructed; the Connecticut River Museum, the Submarine Force Library and Museum, and the Royal Navy Submarine Museum have them on display.
Named for its shape, Turtle resembled a large clam as much as a turtle; it was about 10 feet (3.0 m) long (according to the original specifications), 6 feet (1.8 m) tall, and about 3 feet (0.9 m) wide, and consisted of two wooden shells covered with tar and reinforced with steel bands.
It dived by allowing water into a bilge tank at the bottom of the vessel and ascended by pushing water out through a hand pump.
It was propelled vertically and horizontally by hand and legs-cranked propellers.
It also had 200 pounds (91 kg) of lead aboard, which could be released in a moment to increase buoyancy.
Manned and operated by one person, the vessel contained enough air for about thirty minutes and had a speed in calm water of about three miles per hour (5 km/h)


The LEGO model:



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The model is based on historic data found on the Internet, mostly schematics and from the info.

First I had to create a perfect LEGO ball, 21 studs in diameter, then elongate it at the middle section, and then make the bottom part removable, top section flat, and all four sides removable!
I though it would be easy, but making it was a nightmare.
And time consuming to design a nice eggy shape.
Making the ball's walls thin and strong was a main goal. 

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After few days I had working prototype and some 700 Reddish Brown plates were ordered.
Then bottom section is made of yellow bricks, which simulates the section with lead, to make the whole vessel more stable.
Two rings of 1x1 round plates are made (about 180 pieces), to simulate metal belts that will hold the hull together.

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Then the tower is added, which is 8 studs diameter and 8x8 dish at the top, and it consists of four windows for the operator to see, and breathing hoses with valves at the top.

Lastly all the mechanics is placed inside the hull.

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The model, as the real vessel, have all the functions for sailing above and under the water.

Operator has many levers around him, most importantly is legs driven crank that drives the horizontal propeller, then hand driven lever for driving vertical propeller.
For turning there is a lever at the side, and with a system of levers it operates the rudder.
At the top there is another lever for operating the drill, which is connected with bomb at the back, via the chain. When the drill is drilled into the enemy ship's hull, the Turtle drives away but drill and the bomb hanging on the chain stays on the ship.
In real vessel there were also pumps for regulating water level in the hull, then nosles at the top for inhaling more air (max time underwater with present air is about 30 minutes) and big lead plate for stabilizing the vessel, which could be detached in a case of emergency, when operator needs to quick get to the water level.

All the functions I have incorporated into the model have realistic look and range of motion and are in place where they actually were on the real vessel.

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