Stern tube & intermediate bearings (theory)

This test contains questions about general things you should (or could) know about stern tube bearings. For example about white metal bearings and alternatives, as well for stern tubes as intermediate positions.

In total the test contains 30 questions for which you will get 20 minutes to complete it.

Note: once the test has been started you have the mentioned time to answer all questions, there is no way to stop and re-start the test.


What is the most common name we use for the first type of stern tube bearing?

  • Oak barrel bearing
  • Dead wood bearing
  • White metal bearing

What is the common Dutch word for the first type of stern tube bearing:

The Dutch word for dead wood bearing is: pokhout.

What is the Latin name for the first type of stern tube bearing:

Who is considered to be the inventor of the first white metal bearing:

  • Thomas Edison
  • James Watt
  • Isaac Babbit
  • Alfred Mann

In which time era was the first white metal bearing invented:

The first white metal bearing was introduced in 1839 by Isaac Babbit

  • 1700-1799
  • 1800-1899
  • 1900-1999

Stern tube bearings

Is it possible to repair a damaged white metal bearing:

  • Yes
  • No

Which white metal type is commonly used in stern tube bearings:

  • Magnesium based
  • Lead based
  • Copper based
  • Chrome based

Facts about stern tube bearings:

  • All class demands for bearing lengths are identical
  • Commonly the length of an aft bearing is twice the shaft diameter

Match the products and materials:

  • Tin based bearing
    10% copper / 90% tin
  • Lead based bearing
    5% tin / 80% lead / 15% antimoon
  • Bearing carrier
    GG20 / GG25 / GGG40

Select the base materials which are used for white metal layers for stern tube bearings:

  • Copper
  • Tin
  • Lead
  • Cast iron

Link the characteristics which match most:

  • Lead based bearing
    Higher self lubricating specifications
  • Tin based bearings
    Higher resistance to shock loads

Match the correct class regulations:

  • 2.0 x shaft diameter D
    General class regulation for AFT bearings
  • 0,5 x shaft diameter D
    General class regulation for FWD bearings
  • 2,5 x shaft diameter D
    Specific ABS class regulation for AFT bearings
  • 0,8 x shaft diameter D
    Specific GL class regulation for FWD bearings

Intermediate bearings

On which vessel below is the chance the highest to find an intermediate bearing:

Match the correct OEM's with their type of intermediate bearing:

  • Cedervall
    CED / CEDN
  • Wartsila
    SLB / SLC / FLB
  • Kemel (Kobelco)
    KMS / KMF
  • Blohm & Voss

Facts about intermediate bearings (1):

  • All intermediate bearings are executed with a top and bottom housing part
  • An intermediate bearing can principely be used on every vessel with a propeller shaft

Facts about intermediate bearings (2):

  • All intermediate bearings are mounted on their bottom base plate
  • A plummer block is common name to describe a mounting type of an intermediate bearing

Facts about intermediate bearings (3):

  • If the bearing housing is split-type, the bearing shells can still be non-split (like with a stern tube bearing)
  • An intermediate bearing can have forced lubrication (like shafts can have forged flanges)

Facts about intermediate bearings (4):

  • On some bearings the oil slingers are replaced by conventional lip-type sealing rings
  • It is possible to remetal an intermediate bearing shell

What is the correct name of the bearing type below:

  • Wing mounted intermediate bearing
  • Plummer block intermediate bearing
  • Tunnel bearing

Mark the oil scraper in the drawing below:

Which part needs to be removed to exchange the baffle plate:

  • number 5
  • number 6
  • number 7
  • number 8

Synthetic bearings

Lubrication of synthetic bearings:

Synthetic bearings can be used in  stern tube systems.

What material is used to manufacture the below shown bearing:

  • Rubber
  • Rubber composite
  • Composite
  • Dead wood
  • Nodular cast iron

What is the correct mounting position of the bearing water grooves as shown below?

Please note that shaft is turning counter clockwise.

PT-100 sensor

Where does PT in PT100 stand for:

  • Postion
  • Platina
  • Post

Where does 100 in PT100 stand for:

  • 100 Ohm resistance at 0ºC
  • 100 Ohm resistance at 10ºC
  • 100 Ohm resistance at 100ºC

What type of temperature sensor is shown below:

  • Single type sensor
  • Dual type sensor
  • Triple type sensor

Facts about PT100 sensors (1)

  • A PT100 sensor is used to monitor the stern tube oil temperature
  • All PT100 sensors are made of stainless steel

Facts about PT100 sensors (2)

  • A PT100 sensor can only be used in an AFT bearing
  • In the marine industry all sensors are dual type

Pinpoint the PT100 sensor hole on the drawing below: