Faq

There is a strong prop walk on my boat

Fixed and folding propellers are designed to work well forward but are not designed to have a good performance in reverse, this is due to the fact that when in reverse, a prop turns in the opposite direction than in forward (e.g. right hand instead of left hand), so in a fixed or folding propeller, when in reverse, the water comes in from the trailing edge and goes out from the leading edge (which is the opposite than when in forward). This dramatically impacts the efficiency of propulsion backwards. This means that in backwards the side thrust will be proportionally more important than the thrust in the direction of travel. 

EWOL propellers solve this problem in a smart way….when shifting from forward to backward the blades flip of about 180 degrees, so the leading edge remains leading either in forward and in backwards, hence the efficiency remains identical in both senses of rotation.

 

How much sailing speed can I gain compared to my fixed propeller?

Our tests have shown a gain on sailing speed ranging between 0.5 knots and 1 knot (depending on propeller diameter and other boat conditions).

 

Which motoring speed can reach my boat with an EWOL propeller ?

Each sailboat has its own critical speed (also called hull speed), this is more or less the maximum speed that the hull can do, regardless of the engine power, the type of propeller blades, or other features related to propulsion. EWOL propellers allow to optimize the propulsion such to reach the critical speed of the hull.

The pitch of an EWOL propeller can be easily fine tuned by acting on an external adjusting ring that allows to modify blades angle with incrementals of 0,25 degrees. This corresponds to about 40-50 rpm at each step. The maximum total adjustment range is of 12° (48 different positions), making it by far the propeller with the most precise adjustment on the market and allowing to always find the best results of speed and low fuel consumption

 

How are Ewol propellers performances compared to others on the market ?

It might look strange but many times the original propellers installed on sailboats are not perfectly sized, sometimes are too small, or have an insufficient DAR or they have a wrong pitch. In addition to this, original propellers cannot take into consideration the real conditions of “your boat”, because the manufacturing shipyard could not know if you sail alone or with 6-7 people or more, they don’t know if you have loaded more or less weights (more sails, more equipment, etc), they don’t take into consideration for how many hours your engine has worked….in other words they only knew theoretical conditions.

EWOL Props instead are specifically calculated and tailor made “only for your boat” and in addition they can be fine tuned to the actual conditions. Fine tuning can be easily done, based on the rpm that you have reached on the first trial. As an example, if you engine should theoretically reach a max of 3000 rpm but it actually reaches only 2500 rpm you will have to reduce the blades angle of about 10 steps (2.5 degrees). This will take the max rpm very close to optimal, with one more trial you will find the best angle and best performance !

 

Can I reuse a EWOL propeller on my next boat?

The fine pitch adjustment is also useful in case you want to change engine or boat (within certain limits). For example, if an EWOL customer decides to remotor from a 40 HP to a 60 HP engine, or from a 10 m boat to 12 m it will probably be enough to change the pitch of the propeller.

EWOL propellers employ many components that are identical on different sizes, this because our props are built to withstand high power loads, thanks to the high strength materials employed. This means that in case of more important changes (e.g. passing from 40 HP to 80 HP engines or passing from 10 m to 16 m boats), our customers can send back their propeller to EWOL and with a minimal expense we can replace only some of the components, such as only the blades and the hub and obtain practically a brand new propeller ready to be installed on the new boat.

 

Why EWOL propellers are made of stainless steel? Which are the advantages of these materials?

Most of the propellers are made of bronze, there are various bronze qualities, however all qualities are subject to galvanic corrosion if not properly protected with sacrificial anodes.

Stainless steels used for the construction of EWOL propellers aren't the basic standards commonly used for rigging (e.g. AISI 304 or AISI 316), we only apply Super-Duplex steels

These materials have very high mechanical strength and high resistance to galvanic corrosion. The high stiffness also allows to design with reduced material thicknesses and weight. In fact, an EWOL propeller for boats over 16 m and over 150 HP weighs only 12 kg against the weight of other products on the market weighing more than 20 kgs.

Also the great corrosion resistance of these materials makes them particularly suitable for extreme conditions and in case of moorings in sensitive areas of corrosion, e.g. mooring near overhead lines or metal bodies or in case of residual currents from hulls etc.

Stainless steel propellers are also particularly suitable for installation on boats with aluminium hulls or carbon, because they limit the risk of corrosion of the hulls.

 

I have an aluminium-hulled boat, can I install a bronze propeller?

It is widely recognized by experts in marine corrosion that bronze is not a material recommended for installation on aluminium hulls, though appropriately protected.

It is always better to install a stainless steel propeller.

 

Who can properly install an EWOL propeller ?

EWOL propeller’s installation and adjustment are very simple and intuitive operations which don’t require specific technical skills or tools, the propeller can be installed and adjusted using only two standard wrenches, the 24 mm wrench (or an adjustable wrench) and an Allen wrench for the pitch adjustment. Everything can be done easily directly by yourself or at your usual shipyard / propulsion expert. If you prefer to rely on a company already familiar with EWOL propellers you can find a list of installers in the PARTNERS section of our website.

 

How can I order and how quickly can I receive my EWOL propeller?

On our website under the SHOP ON LINE section you can order your propeller with a simple and intuitive procedure, in less than 10 minutes. The diameter of the propeller can be determined by section CALCULATES YOUR PROPELLER using your boat’s data.

Alternatively you can send us a request for quotation at the section GET AN OFFER

Than we will send you our offer and give you indications on how to place your order

Once you have placed your order we will put your propeller into production and ship your order within 7 and 15 working days from your payment.

 

Which warranties does EWOL offer on quality and performance of its products?

EWOL is so confident about the quality of its products that is the only company offering the following warranties :

-A first “30 days money back warranty”: within one month from shipment date, if the propeller doesn't improve maneuverability performance or sailing resistance compared to the prior fixed or folding propeller, EWOL will accept the return of the propeller and will fully refund the money paid by the customer.

-A unique “3 years limited warranty”, covering any manufacturing defects of the product. 

 

Why did you put the interchangeable bushings on the propeller?

EWOL propeller is a product that does not lose value over time and gives greater value to your boat. EWOL uses advanced technology materials and the interchangeable bushings are an extremely reliable solution to refurbish your propeller even after many years of work in a smart ancd convenient way. If your EWOL prop has worked for some years now and you have noticed some play on the blades, you can buy the "SET OF REPLACEMENT BUSHINGS" in the SHOP ON LINE section on EWOL website.

Usually the refurbish operation on feathering propellers is a costly and difficult operation that could only be done by sending the full propeller back to the manufacturer.  On EWOL propellers instead, this intervention can be made by a local mechanical workshop, anywhere in the world.

 

On what type of boat an EWOL propeller can be installed ?

EWOL props can be installed on any sailboats, monohull or multihull with engines starting from 15 HP up to 350 HP, suitable shaft sizes go from 25 mm (1”) to 55 mm (2”), whether with shaft drive or sail-drive, in the latter case our propellers are equipped with anti-shock FlexDrive joint.

 

How often should I change the zinc anode?

EWOL props are built using galvanic corrosion-resistant steels, however they are equipped with a zinc anode to additionally protect the propeller.

The zinc anode should be changed every year, even in case this is not fully weared out

 

Where can I find replacement for zinc anode and othe spare parts ?

Zinc anodes and other spare parts can be purchased directly on our website in the section SHOP ON LINE or from our PARTNERS

 

How often should I replace the interchangeable bushings?

The wear of the bushings depends on how much you use your propeller and the type of water (salinity, temperature etc.), typically bushing lifetime can vary between 3 and 7 years.

 

How often should I add grease to propeller?

EWOL propellers do not require routine maintenance except for the addition of grease every one or two years. To carry out greasing see operation on instructions manual in the section CUSTOMER SERVICE.

 

My current propeller vibrates, what are the reasons and how can I solve the problem?

There are various possible causes or contributing factors for on-board vibrations, it’s also possible that the vibrations are not generated by a propeller problem, here are some of the possible sources of vibration:

-The propeller is a two-blades model, this type of propellers are always noisier than three-blade models

-The shaft is damaged or bent

-The propeller has a too big diameter and blased are passing too close to the hull

-The propeller took a shot and one or more blades are damaged or bent

-The propeller has not been properly balanced

-The propeller is partially corroded or the bushings are worn

-The propeller cavitates

-The prop is fouled or something is entangled in it

-The key inside the keyway of tapered shaft is too high and pushes the propeller slightly out of the centre of rotation

-Some part of the engine touch the engine compartment out of the silent block

-Engine's silent blocks are worn

-The shaft braket is damaged or has to be fixed or its bushing is worn

Solutions to eliminate the causes of vibrations are therefore different, EWOL propellers are always dynamically balanced in order to eliminate possible causes of vibration generated by the propeller.

 

 

How much speed can I gain compared to my fixed propeller?

Our tests have shown a gain on average between 0.5 knots and 1 knot (depending on propeller diameter and other boat conditions).

  

          

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