To provide this service at the best possible price, Marine Direct Australia offers basic information on which propeller to select and how to ensure the taper in the hub is correct. If you know your existing propeller diameter and pitch and can use a ruler, you can follow our easy step by step instructions. It is also helpful to know the Diameter Area Ratio (DAR) of your existing propeller.

Finished Propellers in the factory

Boxed Propellers ready for freighting

Products:

Use the following information as a guide to begin your selection process.

Group A:
3 Blade DAR 55: Designed for cruising speeds up to 28 knots.
4 Blade DAR 67: Designed for cruising speeds up to 28 knots.

The Group A 3 blade propellers are designed for maximum efficiency on fine fast bottomed boats. They are highly damage resistant and offer smooth performance. If your present propellers are 3 blade, you may also wish to consider replacing them with 4 blade propellers. If you do upgrade to 4 blade propellers the propeller calculations and performance may be somewhat different.

The Group A 4 blade propellers offer smoother increase in speed, less vibration and increased bite in the water. 4 Blade  propellers will provide considerably more transom lift than 3 blade propellers.   If your present boat has 4 blade propellers then only replace them with 4 blade propellers.

In the majority of cases for 17-25 knot cruising Riviera, Bertram, Caribbean boats with average planing hulls, the Group A 4 blade propeller would be a good choice.

Group B:
3 Blade DAR 65: Designed for cruising speeds up to 32 knots.
4 Blade DAR 73 or 87: Designed for cruising speeds up to 32 knots.

Propellers in Group B have an increased Diameter Area Ratio (DAR) meaning the blades cover more surface area in their turning circle.  This increased blade area within the radius of the propeller can help solve cavitation issues. These propellers are more finely tuned than Group A propellers.  They may also require more horsepower due to the increased blade area.

Available Sizes:

We are able to supply propellers from 16" to 40" in diameter in 1" increments. ie. 21", 22" 23" etc.
All the propellers are available in 1" pitch increments ie. 17" pitch, 18" pitch, 19" pitch etc.

Going from 3 blade to 4 blade:

Going from an old 3 blade propeller to a new 4 blade propeller requires an understanding of what the new propeller is doing.   There has been a great improvement in the quality of propeller design and manufacturing techniques in the past 20 years.

1. A four blade propeller has more surface area than a 3 blade propeller, hence the DAR is higher.
2. More power is taken to push a four blade propeller of the same pitch as a 3 blade propeller. ie. you need greater horsepower.
3. A 4 blade propeller is better balanced than a 3 blade propeller.
4. A 4 blade propeller swill provide more transom "lift" as it bites into the water.
5. A 4 blade propeller has greater resistance in the water.

Top speed may be slower than a 3 blade propeller.

Cruising speed and fuel consumption is often improved using 4 blade propellers due to their greater efficiency.
 

Purchase in Steps:

1. Know the pitch and diameter of your current prop.
2. Determine what you need from the replacement props (such as higher/lower RPM' to suite the engine manufacturers specifications for wide open throttle.)
3. Know the existing taper of your current prop shaft. (We can assist you to measure this)
4. Complete a formal order form and pay for the propellers.

Delivery Time:

Delivery time is approximately 3 weeks from the time you place your formal order.

Prices:

Approximate US$ prices are provided in the table below for a range of propeller sizes.  These are for NIBRAL propellers that are computer cut to exact specifications.  They are not faced by hand, but by milling machine.  They are made to ISO Class II standard.

All prices exclude air freight which can range from an average US$200 to US$500 worldwide for two propellers.  Sea freight may be cheaper but air freight is the better option.