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Propeller Guard

What is Propeller Guard?

Propeller Guard

A Propeller is the most important part of ship which helps the ship to move. It is totally submerged in water fitted with blades. On many ships this propeller is fitted with a propeller guard.

A Propeller guard or prop guard is a protection given to the propeller of ship which allows the propeller to rotate freely also protects from underwater obstruction. For e.g. rocks and underwater reefs etc. apart from rocks and reefs propeller guard also protect marine animals which might come in contact with rotating propeller and loose their life.

Propeller Guard is made up of steel which resist to corrosion as sea water is more corrosive.

Working of Propeller Guard

Propeller is surrounded by prop guard which is like a nozzle. This construction of nozzle action moves water with a controlled directional force which gives the boat which enhance the handling of vessel and increases power. This nozzle action is carried out with no moving parts to adjust or replace. The benefit of introducing prop guard is whether you have an outboard or stern drive, Prop Guard will increase propeller efficiency, decrease fuel consumption and improve vessel handling and the same time it reduces hull and engine stress. Technical testing of the Prop Guard has proven that the performance of pleasure crafts is actually enhanced after introducing propeller guard.

Advantages of Propeller Guard

Tests have proven that use of propeller guards does not affects the vessel`s acceleration, turning ability, or ability to keep on steering course of vessel.

Increase in efficiency of Propeller

Propeller Guard reduce or eliminates the need for additional drag producing trim devices. In a steep turn, boats tend to turn on their center of gravity and it is affected by the characteristics of Propeller in the water creating uncontrolled rev-ups. This can be eliminated as the creating a greater lateral area of the nozzle produces a larger effective rudder area. Propeller Guard enhance the thrust significantly to overcome handling problems.

Increase in efficiency of vessel handling

With the help of prop guard handling characteristics were drastically improved, as it increases the lateral area of the nozzle through which creates a larger effective rudder area. There is significantly improves the steering control when vessel is at high speed made 360 degree turns in 30 to 40 feet compared to 60 to 80 feet with propeller not fitted with propeller guard. The stopping distance of the boat is also dramatically increased as the nozzle produces a greater blockage area.

Types of Propeller Guard

There are four types of Propeller Guard we can see on vessels which are as follows:


 It is a conventional type of propeller guard which used on boats.
 Cages with rear screens which swing up to reduces drag.
 It has a retractable cage guards.

Vane Guards

 Flattened vanes are used as a barrier between people and the propeller to reduce accidents.
 Some ships are fitted with hollow vanes that can be shaped like airfoils to reduce drag.

Shrouds or Rings

 It has an extended ring or duct is installed around a prop on an existing drive.
 It includes ring guards with rear screens that swing up to reduce drag.
 This construction contains series of concentric rings, like Prop Guard from Prop Guard Marine, or the Thrustor from Marine Propulsion Technologies.


 In front of propeller or drive, deflectors including drive skegs.
 Deflectors beside, below and behind the propeller.

How do you fit a propeller guard?

A propeller guard can be fitted on a vessel very easily with the help of tools like a wench and a drill. Once propeller is fitted with a propeller guard, a ship owner and the crew can rest assured that there will not be any extra costs incurred to continuously replace the propellers.

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