Whatever type of vessel you require a propeller for you can be sure that Bruntons have the solution – not just any solution but exactly the right one. Why? Because Bruntons are the one company in the world that designs and manufactures just about every type of propeller in regular use today. Whatever your propeller requirements, Bruntons will have the perfect answer.


Varifold folding propellers have taken the market by storm. Regularly fitted by such notable yacht building names as Baltic, Swan, Wally, Moody and Oyster, the complete range of Varifolds has a model for cruiser racing and racing yachts of every size. Varifold is revolutionary in design and brings a revolution to the yachts they are fitted to. Radical reductions in noise and vibration and excellent performance under engine, both ahead and astern, are the result of the propellers unique design. Varifolds have proper helical pitch distribution, including pitch reduction towards the blade tip. This pitch reduction ‘unloads’ the blade tips and, combined with the skewed blades, greatly reduces noisy pressure pulses against a yachts hull. While some other folding propellers have a helical pitch shape, few have proper sections or pitch distribution. None, put all these requirements into a complete package, except Varifold.So advanced is Varifolds design that a 4 blade version has successfully been fitted to a yacht with a 750hp engine, we believe that would have been an impossible task for any other folding propeller. Each Varifold, whatever its size, is built to the same extremely high specification from a nickel-aluminium-bronze alloy which guarantees great strength and high corrosion protection. Cruiser racing and racing yachts can now get the best of both worlds; a folding propeller that combines low drag when sailing, with efficient and quiet power when motoring. Oh, and by the way – Varifolds open in reverse, and not just sometimes!

From 10hp to 1000hp there is a Varifold propeller for your yacht, whether it is a small cruiser racer that does more cruising than racing, or an out an out racer that just needs a propeller to get back into port. Our two, three and four blade versions are designed to produce excellent thrust when motoring with exceptionally low noise and vibration levels, and when folded for sailing, to reduce drag to a minimum. Many well-known yacht manufacturer’s now fit Varifold as standard and the list of yachts re-propped with a Varifold to solve existing problems grows longer.

Bruntons Auto Prop – Perfect Propulsion:

Autoprop’s unique design and superb build quality make it the first choice feathering propeller among cruising yachtsmen the world over, with drag reduction when sailing by at least 85%, and a unique ability to change pitch automatically to suit prevailing wind and sea conditions when motoring or motor sailing. Auto pitching, auto feathering, the same thrust in astern as ahead, less prop-walk in astern, a brand new version for hybrid and purely electrically driven vessels, and a recently developed ability to produce very efficient and economic propulsion for purely diesel powered displacement motor boats are more than reason enough.
Autoprop is a unique propeller which has been praised by yachting writers around the world. Whatever type of cruising sailing yacht you may own, mono or multihull, or displacement motor vessel, leisure or commercial. If you need more information don’t hesitate to contact us.
In the world of leisure yachting our leading brands; the Autoprop feathering propeller and the Varifold folding propeller are acknowledged as world leaders in sailing boat propulsion. Our fixed bladed propellers for motor yachts, commercial and naval craft, are designed and manufactured to the same exacting standards in order to provide outstanding performance.
You can see from the image Autoprop in drive mode. When reversing the blades swing through 180 degrees and produce the same thrust as in forwards. When sailing the blades feather automatically, reducing drag by up to 85%


Autoprop in drive mode
Autoprop feathered
Sigma Drive components
Sigma Drive
Sigma Drive Coupling

Sigma Drive:

What makes SigmaDrives different is their ability to resist propeller thrust when installed as a standalone coupling, directly from the shaft to the output flange on the engine’s transmission. It reduces and even eliminates vibrations that originate from an imperfect alignment between the propeller shaft and the engine, compensating for up to 3 degrees in all directions. This system can also be installed using thrust bearings so that the engine can be placed utilising the space available ergonomically.
SigmaDrives are designed to fit virtually all boats from yachts to workboats, canal narrow boats to military vessels; in fact pretty much any powered vessel with engines up to 1300hp. They are extremely easy to fit, requiring no modifications to the craft, which can usually be equipped with the drive unit whilst still in the water. Together with its anti-noise and vibration abilities having a SigmaDrive on your vessel also ensure that seals and bearings are always perfectly aligned, reducing wear and guaranteeing a longer trouble-free life for all associated components.
This product is for conventionally driven vessels. The system uses a constant velocity joint to self-align the shaft. Thrust taken up on the engine from the propeller invariably changes the angle of the shaft line, particularly when the engine uses soft rubber mounts. Using a single SigmaDrive replacement coupling will ensure the shaft is correctly aligned at all times, especially under high load. The result, reductions in many cases of around 50% in noise and vibration.
The SD standalone unit that resists the propeller thrust compensating for up to 3 degrees in all directions. SD 55, 100, 150, 225 and 300

This system incorporates a thrust bearing to isolate the propellers’ thrust to the engine. It uses a combination of three SD units built together. Two of which are incorporated in the thrust bearing and another coupled to the transmission with an intermediate shaft.
STS Sigma Thurst System STS 550, STS 1000, STS 1500, STS 2250, STS 3000



Without a doubt the greatest innovation that awaits a user of the Bruntons CPP system is its ability to monitor required vessel speed and load, weather conditions and sea state, and then automatically set the correct propeller pitch to keep the required speed whilst maintaining maximum fuel efficiency. The system has different pitch control modes which allow the operator to select the one most relevant to the required operating requirements for example maximum power or, as described earlier, maximum fuel efficiency.​
The highly advanced computerised monitoring system can be used on hybrid powered vessels, not just for propulsion efficiency, but also for battery use optimisation and monitoring and will ensure that the system is optimising regeneration of electricity as well as usage.
Our Naval Architects and Engineers having considered the current limitations of CPP propeller design have produced a system that overcomes two major problems associated with this type of propulsion; excessive blade wear and high spindle loads. Excessive blade wear will be dramatically reduced with the inclusion of a new blade retention system.
Every propeller will be manufactured to the highest standard required for the use the vessel will be put to culminating in ISO class 1 with class ‘S’ pitch tolerances for the craft with the most exacting requirements.
Every propeller will be custom designed for the vessel it is propelling to further improve performance and reduce cavitation.
Pitch distribution across the propeller blades will be carefully designed to provide pitch reduction towards the blade tips. This will create ‘tip unloading’ a feature which reduces propeller pressure pulses against the hull.
Rake and skew of every system will be custom designed to maximise clearance from the hull, strut and rudder.
​The hub will be faired into the aft strut bossing to create smooth water flow into the root sections.
The system will be capable of fully feathering its propeller blades making it ideal for sailing vessels looking to minimise drag and resulting speed loss while sailing. The system will be capable of fully feathering its propeller blades making it ideal for sailing vessels looking to minimise drag and resulting speed loss while sailing.
​On twin-screw motor vessels, when operating requirements allow it, one propeller can be fully feathered providing significant improvements in fuel economy whilst steaming under one engine.

CCP System

Custom, Superyachts and Naval:

Bruntons design and manufacture propellers for naval vessels that are designed for various different uses, from mine hunters to high speed patrol craft. In all cases it is very important that apart from producing the required performance the vessel should have the lowest possible noise ‘signature’.
Superyachts, with regard to propeller design, share several similarities with naval vessels: they are usually highly advanced in both their overall design and construction materials. We often find that the actual design of the vessel can make the installation of a conventional propulsion system difficult or even impossible. In situations like these our experience and specialist knowledge enables us to work very closely with the vessels designers and builders to develop exactly the right propulsion solution for that vessel.
Suffice to say, if you have designed a propeller for a nuclear submarine, which we have, then there is very little which is going to defeat you!
At Bruntons we design and manufacture propellers up to 3 metres in diameter.