Marine Technical Training Academy

 Bonding and Grounding “Bonding” refers to a common connection joining metal components to: Provide a low impedance ground fault path to trip a circuit protection device Prevent dangerous voltages from appearing on metal objects Provide a path for galvanic and DC stray currents “Grounding” is defined as a common connection to Earth for the purpose of: Lightning discharge System voltage stabilization Reducing static and RF interference Bonding or Grounding? Keep in mind that these terms are often used interchangeably in the current lexicon.  We will be focusing primarily on “Bonding” in its classic sense but may also refer to some aspects of this as “Grounding” (e.g. the green wire is called the ground wire, but it’s actually a bonding wire by definition in most cases). Our Priority There are 3 areas we are focused on:  Personal injury and Death, Fires, and Corrosion of underwater metals.  Personal injuries and deaths occur less frequently but the consequences are cat...

 Two-Stroke Engines A two-stroke engine is a combustion engine that completes the cycle in two movements of the piston compared to twice that number for a four-stroke engine. This increased efficiency is accomplished by using the beginning of the compression stroke and the end of the combustion stroke to perform simultaneously the intake and exhaust (or scavenging) functions. The four "cycles" (intake, compression, power, exhaust) occur in one revolution, while in a Two-stroke engine it occurs in two complete revolutions INTAKE  &  EXHAUST First Stroke: Intake + Exhaust for Gas engine In a two-stroke gas engine, the mixture (Air, Gasoline + oil), is injected into the combustion chamber by differential pressure at the first stroke Get here the Marine Diesel Engines Book where you can find all the information on this and many other topics. Get the book INTAKE & EXHAUST (Diesel) Toward the end of the stroke, the piston exposes the intake port, allowing the compressed...

  Carbon Content on Ferrous Alloys Cast iron contains 2 to 4 percent carbon. Carbon steels are classified by the percentage of carbon in hundredths of 1 percent they contain. Low Carbon Steel: Carbon content up to 0.30 percent  Medium Carbon Steel: Carbon content from 0.30 to 0.50 percent  High Carbon Steel: Carbon content from 0.50 to 1.05% Stainless Steel: The carbon content is held to 0.08% maximum. Cast Irons Most cast irons have a chemical composition of 2.5–4.0% carbon, 1–3% silicon, and the remainder is iron. It is usually made from pig iron. Hard skin, softer underneath, but brittle. It corrodes by rusting. Grey Cast Iron Grey cast iron is easily cast but it cannot be forged or worked mechanically either hot or cold. the carbon content is in the form of flakes distributed throughout the metal. Grey Cast Iron Uses White Cast Iron white cast iron has carbide impurities which allow cracks to pass straight through. Since carbide makes up a large fraction of the materi...

 Lightning Protection The combination of vertically moving water droplets and air currents results in the buildup of large quantities of oppositely charged particles within clouds and between clouds and the ground.  The electrical potential differences between charges may be as high as 100’000.000 Volts. By comparison, the voltage on the power lines running along a street is 12.000 Volts. The base of a cloud becomes negatively charged. Since opposite charges attract, the surface of the earth directly beneath the cloud becomes positively charged. The base of a cloud becomes negatively charged. Since opposite charges attract, the surface of the earth directly beneath the cloud becomes positively charged.  It is very difficult to study lightning for many reasons. It occurs very randomly even within ideal conditions and varies greatly in its attributes; a bit akin to snowflakes, no two lightning bolts are alike. Get here the Marine Electricity Handbook where you can find all ...

 ROBOTICS Robotics is the branch of technology that deals with the design, construction, operation, structural disposition, manufacture, and application of Robots.  Robotics is related to the sciences of electronics, engineering, mechanics, and software The word robotics was first used in print by Isaac Asimov, in his science fiction short story "Liar!", published in May 1941. ROBOTS A robot is a mechanical intelligent agent which can perform tasks on its own, or with assistance. In practice, a robot is usually an electro-mechanical machine  which is guided by computer and electronic programming. Robots can be autonomous or semi-autonomous.  Get here the Marine Electronics Book where you can find all the information on this and many other topics. Get the book ROBOTS COMPONENTS Mechanical part or manipulator (Body, Arm, Wrist). End effector (Tool or Gripper). Actuators (pneumatic, hydraulic, electric) Controller (Sensors, Processor) Power supply Vehicle (optional). A ...