Boat Props

Each boat has a different set up and it is important that the propeller give the best possible propulsion for the boat setup. The ideal propeller will give 5000 to 5200 rpm for a two stroke motor and 5200 to 6000 rpm for a four stroke motor.

The blades of the prop are important components of a prop. There are three blade and four blade propellers. Four blade propellers give better overall performance and easy acceleration. They also give better cruising speed; they help to save fuel and enable easy handling of the boat. For boats that carry weight or tow skiers four blade propellers are a better option. For speed boats, the three blade propeller gives better top end speed.

The pitch of the propeller is an important component because the pitch measures the forward movement of the boat after one complete rotation of the prop. If there are two propellers then both pitches should be the same for optimum performance. A high pitch increases speed. However a high pitch may not be good for ski boats or boats that require hole shot performance. Medium and low pitches ensure better hole shot performance. The more expensive but variable pitch propeller is ideal for boats that are used for two or three different purposes and needs variations in pitch.

Props are made of different metals and material. Early propellers were made of bronze. These props are still used in inboard motors. The more durable and lightweight aluminum is the commonly used metal for props today. Aluminum is a fairly durable metal for props. The advantage is that when aluminum hits an obstacle it shatters and prevents the collision from impacting other parts of the engine system of the boat. Aluminum corrodes easily and is unsuitable for sea water. Stainless steel is an expensive alternative to aluminum. Stainless steel is resistant to salt water and gives better speed for the boat. However, if the prop hits an obstacle the impact causes a jolt to the propeller and the vibrations of the jolt affects the entire engine system. Alloy props, composite props and plastic props are newer high performance and inexpensive propeller options available in the industry today.

The propeller that is ideally suited for boats depends on the purpose of the boat. Different props are required for boats used for fishing, leisurely cruising, towing skiers or using the boat as a speed boat in races. The manual of the engine is a guide to the ideal propeller for the boat. Once the correct prop for the boat is fitted it will give the boater hours of comfortable boating.