Propeller Polishing

The propeller is an important part in the ship, Underwater propeller inspection & repair & polishing is very important for ship. 

For this reason the tactics of propeller inspection & repair is necessary. 

Any deformation to the actual shape of the propeller may cause imbalance in its operation, vibrations, which in turn cause an increase of cavitation, loss of thrust control, leading to damage to the tail-end shaft and an increase in fuel consumption. 

Propellers should always be kept in excellent condition. The main factors that reduce the optimal operation of the propeller is pollution, cavitation and damage due to hits. Any deformation of the actual shape can cause imbalance and therefore vibration, which in turn causes increased cavitation, loss of thrust control, leading to damage to the tail-end shaft and increase in fuel consumption. The underwater propeller repair is the fastest, most efficient and most economical way to repair the propeller of the ship, since it keeps it away from the dry-dock, which on one hand takes a long time and on the other hand has a very high cost. 

Usually involves damage caused to the edge of one of the blades.  A ship with bent or cracked blades can suffer severe vibration and cause engine overload at sail. For this reason the propeller repair is necessary to obtain approval from the ship classification society for sailing. Prior to the underwater propeller repairs a detailed underwater inspection is carried out, the problem is analyzed and the  best solution for underwater propeller repair is decided in consultation with the technical department of the ship owning company.
     

The propeller shaft is strained because of the disorder generated from the balance of the weight thereto. Thereby creating hazardous loads on the shaft bearings system due to the constant vibration and the risk of causing serious damage. For this reason it is necessary to balance the propeller (underwater balancing propeller) on the rotating shaft to prevent stress from the centrifugal force, thus contributing to a better hydrodynamic behavior. 

The underwater propeller polishing (multi-stage micro polishing of all surfaces)and the maintenance of the smooth surfaces,is vital in order to save energy and optimize the performance of the ship (improvement of vessel’s performance). The rough propeller leads to power loss, which can be up to 5% as well as an increase of fuel consumption. 
   

An important problem in shipping is the increase of roughness to the ships propeller, as the fuel consumption and the emission of gaseous pollutants in the environment is increased and significant losses are caused to the propulsion system. 

Performing therefore underwater propeller polishing (uw propeller polishing), significant advantages are presented over the ever-growing subsea pollution (underwater fouling). The advantages of the underwater propeller polishing (uw propeller polishing) are:  

1)Increase and improvement of vessel’s performance

2)Reduced fuel consumption up to 5%

3)CO2 emission reduction of gases in the marine environment

4)Increase of vessel’s (vessel’s speed)

5)Reduction of unwanted vibrations due to cavitation (reduction of vibrations by cavitation)

6)Stress Reduction of the propeller axis and the vessel’s machinery (stress of the vessel's machinery)

7)The propeller and rudder are cleaned simultaneously, to further enhance the performance of the vessel (propeller and rudder)

8)Increased reliability

9)Expansion of vessel’s maintenance cycles (expansion of vessel’s maintenance).

As a response measure is the planned underwater cleaning and underwater propeller polishing (smoothing, uw propeller polishing). Most often it is customary to make the underwater propeller polishing (uw propeller polishing) in dry–dock, i.e. over approximately 2.5 to 4 years, which is a long time period to be able to say as that the propeller has maximum hydrodynamic efficiency. The underwater propeller polishing (uw propeller polishing), presents more benefits compared to the execution of the corresponding works via dry docking.  The process of underwater propeller polishing (uw propeller polishing) is usually conducted within 1½ – 3 working hours, while the ship is at the berth, thus saving both cost and docking time. Also underwater propeller polishing (uw propeller polishing) represents a faster process because of its natural lubrication of the liquid element, a process that has lasting and better results.

Shenzhen Haili Diving Enginering Co.,Ltd. provides high quality underwater cleaning and underwater propeller polishing (uw propeller polishing), achieving immediate and effective reduction of fuel consumption and reduces the total cost of the ship. Propellers convert mechanical energy to the propeller shaft to thrust energy in the water. 

The underwater propeller polishing (uw propeller polishing) is now part of the regular ship maintenance. The underwater services company  Shenzhen Haili Diving Enginering Co.,Ltd. performs underwater propeller polishing (uw propeller polishing) with diamond disc pads, achieving excellent results [Rubert “B+/A” scale (1.00 Micron Ra)]. 

Shenzhen Haili Diving Enginering Co.,Ltd. has extensive experience in underwater propeller repair, having experienced professional divers with specialized training. Any deformation to the actual shape of the propeller may cause imbalance in its operation, vibrations, which in turn cause an increase of cavitation, loss of thrust control, leading to damage to the tail-end shaft and an increase in fuel consumption.