Because of the materials used in their construction, marine propellers are corrosion-resistant. They use an alloy containing aluminium and stainless steel and are operational immediately in seawater.
Ship owners will need a proper backup from reliable propulsion service providers to ensure timely maintenance and business continuity. They provide the best solutions by offering the services of a specialist team of engineers. Let us now check out the propeller types.
Fixed Pitch Propeller (FPP)
A propeller of any ship typically has a fixed pitch, which means they have the same number of teeth along its whole axial length. This ensures there is sufficient torque for movement even when one of the rotating blades is not producing any power because of wind resistance or other factors degrading the efficiency of the engine.
Controllable Pitch Propeller (CPP)
Variable Pitch propellers are another name for Controllable Pitch Propellers (CPP). There is a relative difference in the root section of the orientation of the blades in relation to their pitch or twist. Thus, it is able to adjust all other blade parts that had previously been at angles. They acquire fresh ones.
Advantages and disadvantages of CPP and FPP
The applications and their connections to the benefits and drawbacks of CPP and FPP systems are covered in the following points:
- Without changing the rotational orientation of the engine, the ship can be driven in both the forward and astern directions using controllable pitch propellers.
- The ship can be propelled forward or astern using a non-reversible engine. As a result, the weight of the engine and propulsion machinery is significantly less than that needed for propulsion systems with fixed pitch propellers.
- A change in the pitch angle can result in a change in the ship’s speed since the pitch of the propeller controls how much power it produces. In order to change the speed of the ship without altering the speed or rpm of the main engine, an adjustable pitch propeller is helpful.
- Because of the aforementioned factor, the ship’s speed can be managed directly from the navigation bridge. Fixed pitch propellers require intimidation from the marine engineer in order to modify the ship’s speed. As a result, CPP technology is employed to achieve a quicker response to speed change.
- Fixed pitch propeller efficiency in an astern condition is lower than the efficiency of a controllable pitch propeller in an astern condition.
However, using a controllable pitch propeller as opposed to a fixed-pitch propeller has numerous drawbacks. It is crucial to be aware of them as well.
- The hub’s installed pitch control mechanism is sufficiently complex to necessitate adequate inspection on a frequent basis. Comparing the installation method to a fixed-pitch propeller system, it is likewise more difficult.
- The initial cost of propellers with adjustable pitch is extremely costly. And when the propeller’s diameter increases, this cost rises quickly.
- When compared to fixed-pitch propeller systems, the hub’s length and diameter are higher due to the pitch control mechanisms located inside.
To sum up, understanding the uses of controllable pitch propellers is crucial. These are employed in ships that must run at varying speeds while consuming a fixed amount of electricity. These vessels include gas turbine-powered tugs, trawlers, ferries, icebreakers, and small warships.