What is a stern tube seal?
Stern tube seals for inland and seagoing vessels The aft seal prevents seawater from contaminating the stern tube oil, which may possibly jeopardise the lubrication properties of the oil, leading to extensive bearing wear. The aft seal also prevents oil leaking into the marine environment.
Where is stern tube fitted?
aft peak
The stern tube is fitted at the stern frame and internal framing of vessel’s hull at aft peak. This allows the tail shaft to rotate smoothly in the bearing area for uninterrupted propulsion.
What is the purpose of stern tube onboard?
The main function of stern tube bearings is to allow an unrestricted and smooth rotation of the propeller shaft. Apart from stern bearings, the stern tube also houses water and oil sealing glands known as the stern glands. The stern tube is a sensitive part of the ship where the sea water can easily seep inside.
What is simplex seal?
Simplex oil-lubricated sterntube seals are designed for oil-lubricated propeller shaft bearings and have two key purposes – firstly to prevent the leakage of oil into the engine room or water, and secondly to keep water out of the sterntube.
Why stern tube seals are provided?
Stern tube seals are a key component of the propulsion system of a ship. The purpose of these sealing rings is to ensure a reliable sealing condition, preventing the spillage of lubricant to the environment.
Which is the best material for stern tube seal?
Materials such as fibrous rope, oakum, carbon and graphite based materials have been used for as long as there have been rotating shafts driving ships through the world’s oceans.
What prevented the water from entering the stern tube?
Lip seals are seals made of special kind of materials (elastic) , having a projecting lip or edge. This peculiar shaped ring is held in close contact with the shaft and the stern tube to prevent oil leakage or water entry.
How do you check stern tube bearing clearance?
How to check Stern tube wear down? ( Lignum Vitae, water cooled stern tube)
- Measurement can be taken by Wedge Gauge or Feeler.
- If Wedge Gauge is used, the side of the Wedge contacting the bearing is chalked and inserted into the clearance space between top of the screw shaft and bearing.
What is a lip seal?
Lip seals serve to protect lubricated moving parts and they do this by keeping the lubricant inside the bearing, and keeping contamination from dirt or other liquids out. The term lip seal is generally used to refer to what is correctly known as rotary shaft seals or oil seals or radial shaft seals.
What will you do if you find oil leaking from stern tube?
Feed oil from the stern tube tank keeping the oiling line valve closed for 3 and 3s seals. Open the drain plugs of chambers 3 – 3s of aft sealing and 4 – 5 of forward sealing to check oil leakages. Shut the drain plug of 3- 3s chamber and open oiling line valve to feed oil to 3 – 3s chamber in the aft sealing.
What is a stern tube sealer?
Stern tube seals. A stern tube is the connection between the propeller and the main engine. The stern tube is a hollow tube which accommodates the bearings, the seal boxes and the propeller shaft. The stern tube is filled with oil, grease or water and forms a barrier between the water outside and the engine room inside the vessel.
What type of stern tube is used on a ship?
Oil-lubricated stern tube systems are the most common but occasionally ship owners require a water-lubricated or grease-lubricated stern tube system. Second, depending on the ship design, the stern tube can be supported with struts or can be positioned within the ship’s hull.
What is a stern tube on a propeller?
A stern tube is the connection between the propeller and the main engine. The stern tube is a hollow tube which accommodates the bearings, the seal boxes and the propeller shaft. The stern tube is filled with oil, grease or water and forms a barrier between the water outside and the engine room inside the vessel.
Where is the outboard seal located on a boat?
The outboard or aft stern tube seal is located at the aft end of the stern tube. The seal’s housing is connected to the ship’s stern tube bossing and the liner is fixed on to the propeller hub.
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