(1) 2. Stern tube sealing systems and bio oil (theory)

This test contains questions about subjects you should (or could) know about the theoretical side of stern tube sealing systems.  Questions included are related to different types of sealing systems, different types of lubrication, oil schedules and bio degradable oil.

In total the test contains 55 questions for which you will get 30 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.

Key sections

Match the sealing ring profiles with the mentioned numbers:

  • 1
    CX / X-type
  • 2
    MK2
  • 3
    SC2
  • 4
    SC1 / C

Which OEM produced this sealing system (1):

  • B&V
  • ATZ
  • Wartsila
  • DSS
  • KEMEL
  • Wartsila

Which OEM produced this sealing system (2):

  • B&V
  • KEMEL
  • Versitec
  • IHC Sealing Solutions
  • Eagle
  • Wartsila

Which OEM produced this sealing system (3):

  • B&V
  • KEMEL
  • Eagle
  • IHC Sealing Solutions
  • Versitec
  • Wartsila

Which OEM produced this sealing system (4)

  • B&V
  • KEMEL
  • Eagle
  • Wartsila
  • IHC Sealing Solutions

Drag and drop the correct manufacturers and sealing ring types:

(Put the maker at the top position, type at the bottom position)
  • Wartsila
  • Blohm & Voss
  • Eagle
  • Kobelco
  • IHC
  • Kemel
  • X-type
  • Supreme-type
  • MK2-type
  • SC1-type
  • H-type
  • SC2-type

In which periods are the mentioned sealing systems supplied?

  • SC2
    1992-2016
  • MK1/SSA
    1955-1972
  • MK2
    1973-present
  • SC1
    1973-1991
  • X
    1990-present
  • SC3
    2016-

Which type of sealing ring has a "roof" head?

  • SC3
  • SC1
  • MK1
  • MK2
  • GS
  • CX
  • DX

Which type of sealing ring has a "butterfly" head?

  • MK1
  • MK2
  • SSA
  • SC1
  • SC2
  • C
  • CX

Which type of sealing ring has a "rectangle" head?

  • SSA
  • SC1
  • SC2
  • SCX
  • C
  • X
  • MK1
  • MK2

What type of sealing rings can be fitted in this seal assembly:

  • HDMY
  • SSA
  • MK1
  • MK2
  • Sublime
  • J
  • K
(click on the answer(s) which are correct)

What type of sealing system is this?

  • CX / X-type
  • SC1
  • SC2
  • SC3
  • MK2
  • Supreme

Differences between several sealing systems?

has a click system to install the sealing rings in their housing

has a round compression area

has the same lower part as the SSA/MK1 sealing system

has a guiding ring in the AFT seal assembly

can be equipped with a Net Stopper on the AFT seal assembly

MK1/4SC/MK2/4BL/SC2(m)/X-type

Drag and drop the mentioned parts to the correct positions:

  • Propeller
  • Stern frame
  • Seal box
  • Ropeguard
  • Net-pickup
  • Monitoring pipe

FWD seal tank

  • Same height as the gravity tank
  • 1 meter above shaft centre line
  • 1 meter below shaft centre line
  • 2 to 3 meters above LWL
  • 2 to 3 meters above shaft centre line
Where is a FWD L.O. tank positioned in a FWD MK2 sealing system with 2 sealing rings:

Space packings

  • To equalize the pressure between the housing parts
  • To seal the upper part of the sealing rings
  • To decrease the compression of the upper part of the sealing ring

Why are space packings used?

 

 

 

 

Retrofit Manebar sealing systems

  • The shaft size is to small
  • No space to install a liner
  • The build-in length is too small
  • There is not enough cooling capacity

Why is it difficult to retrofit a Manebar to a lip-type sealing system?

 

PRIME spacer ring

  • Stock PRIME spacer rings fit in any standard MK2 / SC1 / SC2 / CX type sealing system
  • Stock PRIME spacer rings fit in any standard SSA / MK1 / J type sealing system
  • Stock PRIME spacer rings fit in any standard Manebar outboard sealing system
What is true about our standard stock spacer rings:

Gravity tank MK2

  • 2-3 meters below LWL
  • 2-3 meters above LWL
  • 2-3 meters below BWL
  • 2-3 meters above BWL
Where is the gravity tank (or header tank) in a "normal" MK2 sealing system positioned?

Recognizing PRIME seal components

  • Spare seal
  • Split liner
  • Split housing
  • 2/3 Monitoring sysetem
  • Spare seal activation piping
  • Aegir Protection System (APS)
  • Net stopper
  • PRIMAIR system
  • Peek pressure absorber
  • Special water sealing ring on position #2
  • Liner insert strips
  • Extra long weardown gauge for weardown on cover ring
  • In Water Survey system (IWS)

Can you see what options are applicable on this PRIME sealing system?

(click on the answer(s) which are correct)

CCM Circulator

Mark the position where the circulator (or CCM) should be located:

Net Stopper

  • The Net Stopper is rotating with the shaft
  • The Net Stopper is fixed in the seal housing
  • The Net Stopper is placed loose tightened in the seal housing

What is true about the Net Stopper?

Unnet or APS

  • 45 minutes at 90 degree Celcius
  • 90 minutes at 130 degree Celcius
  • The APS / Unnet profile will not be bonded
How much time do you need to bond an APS or Unnet profile?

Bronze casting

  • Round casting, poured in a mold made of sand
  • Round casting, poured by centrifugal force
  • Round casting, poured in a fast rotating mould
The bronze that is used for PRIME retrofit's is centrifugally casted. What is a centrifugal casting?

Sheet packing or o-cord

  • The FWD liner could use a sheet packing as well
  • The clamp ring has two leakage gaps and a sheet packing can only seal one
  • An o-cord is easier to exchange when leakage occurs
  • The FWD liner needs a dynamic seal so a sheet packing would not last long
The FWD liner is installed with an o-cord, while the aft liner uses a sheet packing (and sometimes an o-cord as well). Why don't they use a sheet packing on the FWD liner?

Dual gravity tank system

In the current situation, this vessel has a draft of 10 meters.

Mark the position of the gravity tank that should be operational:

Activating the standby sealing ring

The high level alarm of the monitoring tank is activated. Samples indicate that no water is found in the lubrication oil.

Mark the valves that need to be closed to activate the standby sealing ring:

 

Damaged sealing ring #1 and #2

The high level alarm of the monitoring tank is activated. Samples indicate that water is found in the lubrication oil.

Mark the valves that need to be closed to stop the water ingress:

Net-pickup system

Mark the position of the Net-pickup system

System facts about lip-type seals (1)

  • IWS is short for "In Water Support"
  • MK2 is short for Mark 2

System facts about lip-type seals (2)

  • Sublime is a sealing system made by IHC
  • SC1 and SC2 is short for Seal Compact 1 or 2

System facts about lip-type seals (3)

  • Cast iron liners are found on FWD and AFT seals
  • Aegir-Marine supplies chrome steel and cast iron liners
  • Cast iron AFT housings need to be protected against corrosion

MK2M

On which picture/drawing is a seal type MK2M shown?

Monitoring

Mark the position of the AFT monitoring tank:

Unnet/APS

  • It rotates with the propeller shaft / liner
  • It is a water tight seal
  • The spring applies a very low force and is positioned without tension in the rubber profile
  • Is made from VITON material
  • Can be used for AFT and FWD seals
  • It is installed to stop nets and fishing lines for entering the seal box
What is true about the Unnet or APS:

EVK / PRIME Blue / Manebar

What material is used for the following sealing systems:

  is made from NBR

​​ is made from HNBR

Drag and drop the mentioned parts to the correct positions:

  • Shaft earthing device
  • Inflatable seal
  • EVK Seal
  • Spare seal
  • Mating ring
  • Propeller shaft

System facts about Manebar (1)

  • EJ
  • EL
  • EK
  • EN
What kind of Manebar is this?

System facts about Manebar (2)

  • can be used for oil, grease and water lubricated systems
  • is a face type seal
What is true about the Manebar:

System facts about Manebar (3)

  • The Manebar type EJ and EL need a clamp ring
  • The seat ring rotates with the propeller shaft

System facts about Manebar (4)

  • For the FWD oil lubricated version, forced seat cooling is necessary
  • Manebars are available with a carbon insert

System facts about Manebar (5)

  • Manebars can be excecuted in Neoprene and Viton
  • The Manebar AFT seal can be excecuted with a monitoring system

Which sealing system is not a copy of an EVK seal?

  • PRIME Blue
  • Maprom GS
  • Sternkeeper
  • B&V Simplan

Match the wear and replacement parts of an EVK seal assembly:

  • Mating ring
    Machine when grooves are >0,5mm
  • Sealing ring
    Replace when leakage occurs
  • Inflatable seal
    Replace every 5-6 years
  • Housing parts
    Lasts for a vessels lifetime
  • Carbon brush of shaft earthing device
    Replace every year

What kind of seal assembly is displayed:

  • Manebar EK
  • Manebar EJ
  • Manebrace MN
  • Simplan

Tungsten/Ceramic

System facts about tungsten / ceramic (1):

  • Tungsten is harder than ceramic
  • Tungsten can only be grinded with a diamond grinder

System facts about tungsten / ceramic (2):

  • A ceramic layer can be machined off on a normal lath
  • A tungsten layer can be machined off on a normal lath

How is a tungsten layer applied on a liner?

  • The tungsten is heated to the melting point, than sprayed on the liner
  • The tungsten Is sprayed on at high speed (800m/sec)
  • The tungsten is sprayed on, than 'baked' in a oven at high temperature for 8 hours (>850 degrees Celcius)

What is true about tungsten / ceramic layers:

  • Thickness of the ceramic or tungsten layer is about 0,5-1,0 mm thick
  • Ceramic is a dens layer and doesn't need filler after it is applied on a liner
  • Tungsten has a better thermal conductivity than ceramic

What is an other name for tungsten?

  • Ferro Carbide
  • Titanium Carbide
  • Wolfram Carbide
  • Nitro Carbide

Bio degradable oil

Systems facts about bio degradable oil (1)

  • Approved bio oil needs to break down 60% in 28 days
  • Changing from petroleum based oil to EAL without changing the sealing rings, is technically infeasable

Systems facts about bio degradable oil (2)

  • Approved EAL oils needs to be minimally toxic
  • Vessels can change to bio degradable oil without going in to dry dock

Systems facts about bio degradable oil (3)

  • Hydrolysis can occur with a combination of esters, water and a high temperature
  • Not all esters can be hydrolysed

Systems facts about bio degradable oil (4)

  • Unsaturated oils are less stable against hydrolysis than saturated oils
  • Polyolesters (sterically hindered esters) are the most stable types against hydrolysis

Where does VGP stands for?

  • Vessel General Permit
  • Vorm Green Pollution
  • Vessel General Pollution