It's revolutionary so the Axiom Propeller raises a lot of questions

As with any new product that makes bold claims to be innovative, the Axiom has raised a lot of questions. As a father and son team working as all great men do, out of a shed, we don’t claim to know all of the answers. Nor would we try to fully explain the science behind the Axiom’s success. However, many of our critics have assumed that this means the Axiom can’t work. Well we’ve attempted to answer some of the more commonly asked questions about the improvements the propeller has been noted to provide.

What makes the Axiom Propeller different to a standard marine screw?

The hub of the Axiom Propeller is the same as a marine screw, i.e. the bore and the key. No alterations to the boat shaft are necessary. The overall diameter of an Axiom is the same as the marine screw as is the Disc Area Ratio (DAR).

A marine screw’s blades are twisted from root to tip. This twist is referred to as “pitch”. A marine screw is a shortened version of the Archimedean screw, c.250BC (patented by Francis Pettit Smith in 1883) and works on the principle that for each revolution of the screw, the vessel travels forward by the same distance. For example, one revolution of a 12” pitch marine screw results in the vessel moving forward by 12”. That’s the theory, but, slip, wake and cavitation all play a part in drastically reducing the pitch.

The blades of the Axiom Propeller are so different to anything else invented that we have been granted a patent. The blades have been described as spade like with straight cutting and trailing edges. This gives the Axiom Propeller the ability to shear the water uniformly across the entire blade length at the same velocity, avoiding peaks of water pressure that lead to cavitation. The water then smoothly passes over the width of the blades which are symmetric in curvature, propelling the water and the vessel a predetermined distance. The advancement is controlled by the engine RPM, horsepower and gearbox ratio.

The blades are a different shape. What other things set the Axiom Propeller apart from the marine screw?

After fitting as Axiom Propeller you will notice changes to your boat’s handling when she hits the water. When reversing out of the dry dock or lifting slings, please do not rev your engine in astern as you would with a marine screw. Set the RPM at just above tick over. Your boat will glide backwards with very little to no prop walk. During a trial conducted by Yachting Monthly, the Axiom’s side thrust was measured with a load sensor. A Kg force of 16.8 was recorded compared to 24.1 for a marine screw. An enormous drop. With the helm amidships you will be able to steer your boat astern.

Moving from astern to ahead, once up to stopped, you will notice the lack of wild, white, turbulent water. The Axiom’s wake is smooth and flat with no hump. The helm/tiller will feel firm, the reaction time of the boat faster with tiller pulsing drastically reduced. For longer trips this means that your autopilot will not be working as hard, reducing the amount of electrical power consumed. If you are of the old school and judge your vessel speed by boat wake, you will be travelling faster with the Axiom for the same amount of wash. Have a care, you could be exceeding the speed limit!

Stern slump (squat) is far less with the Axiom meaning that your stern floats higher, by 3-4 degrees, resulting in improved shallow water performance and, on restricted waters (canals and rivers), less drag on moored vessels, less wash and therefore less erosion.

Motor sailing with an Axiom is a joy as there is less slump. The mast is at a better angle and the sails respond as they would when not motor sailing. You will find that she will react to gusts and you will not have that feeling of dragging a bucket.

Stopping your boat with an Axiom will take a shorter time and distance than it takes with a marine screw. In the Yachting Monthly trial the Axiom stopped the boat from 6mph in 7.1 seconds. The fixed blade marine screw took 9.7 seconds and the other folding and feathering marine screws took 12-13 seconds.

Why is the Axiom Propeller more expensive than a conventional marine screw?

We are more expensive when compared to an off the shelf marine screw but many of these screws have been made from poor material and are prone to poor performance, vibration, noise and wear. All Axiom Propellers are cast in the UK using only virgin stock material. We also use a higher grade (AB2) than normal marine screws. We have chosen this high grade because the blade shape of the Axiom performs better from being as thin as possible. By using AB2 we can reduce the blades’ thickness but not its strength.

Also, the Axiom Propeller you receive will be made to suit your boat and will make full use of your engine power and the specific fuel that you use. A fuel saving of 5-7% has been noted but is tricky to prove. Every Axiom Propeller that we craft is tested in our works to ensure that it will perform for you, giving you less noise and vibration.