The fixed and foldable propellers are designed to perform well or rather well in forward gear, but they are not designed to perform well in reverse gear, so there is currently no possibility that a fixed or foldable propeller will provide good manoeuvrability for the boat in reverse. . Instead, EWOL propellers have a specific profile that provides excellent manoeuvrability and efficiency, identical for forward or reverse gear.
Each displacement boat (sailboat) has its own critical speed (also called the hull speed), this is the maximum speed that the hull can move at, regardless of engine power, type of propeller, blades or other characteristics related to propulsion . EWOL propellers always allow you to reach the critical speed of the hull, because the pitch can be easily set by means of a special external adjustment ring nut that has micrometric positions. The minimum variation is 0.25 degrees, which corresponds to about 2% of the maximum engine revs. The total maximum adjustment range is instead 12°, it follows that the propeller has 48 pitch setting positions, making it absolutely the propeller with the most accurate regulation on the world market.
As mentioned, EWOL propellers always allow you to reach the critical speed of the hull, the fixed and foldable propellers instead have no possibility of pitch adjustment, so if not perfectly calculated they will not provide sufficient performance and could in some cases not reach the critical speed of the hull .
In addition to normal deterioration of engine conditions following many hours of use, naturally the propeller without pitch correction cannot be re-adapted to the new conditions of the engine, so it will lose performance.
On the other hand, the feather propellers (with adjustable pitch) of the competition have the possibility of adjusting the pitch, however these adjustments are too coarse and often do not allow you to reach the desired number of revs, with minimum adjustments of 2° or 2.5°, the effect on the maximum engine revolutions is a minimum of 16% (e.g. from 3300 rpm max to 3830 rpm max without intermediate solutions).
With an EWOL propeller, each adjustment notch will change the maximum speed by 50 rpm, then going towards the – (minus) (e.g. -0.25, -0.50, -0.75, etc.) at full throttle, the maximum number of revs will go up as follows: 3350, 3400, 3450. While if it goes to + (plus) (e.g. +0.25, +0.50, +0.75, etc.), at full throttle the maximum number of revs will go down, as follows: 3250, 3200, 3150, thus allowing an optimal calibration of the maximum number of revs, and consequently the number of cruising revs.
Inoltre al normale deteriorarsi delle condizioni del motore dopo molte ore di utilizzo, naturalmente l’elica senza correzione di passo non potrà essere ri-adattata alle nuove condizioni del motore, quindi perderà prestazionalità.
Le eliche a bandiera (a passo regolabile) della concorrenza invece hanno possibilità di regolazione del passo, tuttavia queste regolazioni sono troppo grossolane e spesso non permettono di raggiungere il numero di giri desiderato, con regolazioni minime di 2° o 2,5° l’effetto sul numero di giri massimi del motore è di minimo il 16% (es. da 3300 giri max a 3830 giri max senza soluzioni intermedie).
Con un’elica EWOL, ogni tacca di regolazione farà variare il regime massimo di 50 giri/minuto, quindi andando verso il – (meno) (es. -0,25, -0,50, -0,75, ecc.), a tutto gas il numero di giri massimo salirà, come segue: 3350, 3400, 3450. Mentre se andremo verso il + (più) (es. +0,25, +0,50, +0,75, ecc.), a tutto gas il numero di giri massimo scenderà, come segue: 3250, 3200, 3150, permettendo quindi una taratura ottimale del numero di giri massimo, e di conseguenza del numero di giri di crociera.
The micrometric adjustment of the wide-range pitch is also useful if you want to change engine or boat (within certain limits). For example, if an EWOL customer were to change from a 40 hp engine to a 50 hp engine, or from a 10m boat to a 12m boat, it will most likely be enough to change the propeller pitch.
However, EWOL propellers use many identical components between one version and the other as they are built to withstand very high power and work loads, due to the technological solutions and exceptional materials used in construction. It follows that even in the case of the most significant changes (e.g. power ratings that go from 40 hp to 80 hp or lengths that go from 10m to 16m), sending the propeller to the manufacturer, with a minimum cost, you can replace only a few components of the propeller, for example the blades and the hub, and have a restored and practically new propeller that can be installed on the new boat.
Le eliche EWOL comunque utilizzano molti componenti identici tra una versione e l’altra poiché sono costruite per resistere a carichi di potenza e lavoro molto elevati, grazie alle soluzioni tecnologiche ed agli eccezionali materiali adottati per la costruzione. Ne consegue che anche nel caso di variazioni più importanti (es. potenze che passano da 40 cv a 80 cv oppure lunghezze che passano da 10m a 16m), inviando l’elica alla casa madre, con una spesa minima si potranno rimpiazzare solo alcuni componenti dell’elica, ad esempio le pale e il mozzo ed avere un’elica ripristinata e praticamente nuova da installare sulla nuova imbarcazione.
Traditional propellers are made of bronze, there are various qualities of bronze, however all qualities are subject, to a greater or lesser degree, to galvanic corrosion, if they are not duly protected with galvanic anodes.
The stainless steels used for the production of EWOL propellers are not trade standards (e.g. AISI 304 or AISI 316), they are steel with very high mechanical and corrosion resistance.
These materials was chosen to provide a product with high mechanical strength, that can withstand heavy loads, while maintaining a reduced profile and low resistance to penetration in water, together with a reduced weight. In fact, EWOL propellers for boats over 16m and 150hp weighs only 12 kg compared to the weight of our competitors’ products, which weigh 18-22 kg, even more in some cases.
Moreover, the great corrosion resistance of these materials make it particularly suitable to extreme conditions and, in the case of moorings in areas that are particularly sensitive to corrosion, e.g. in the case of mooring near the catenaries or metal bodies or in the event of residual currents from the hulls, etc.
Stainless steel propellers are also particularly suitable in the event of installation on boats with aluminium or carbon hulls, as they limit the risk of corrosion of the hulls.
It is widely recognized by marine corrosion experts that bronze is not a recommended material for installation on aluminium hulls, even if it is duly protected.
It is always better to install a stainless steel propeller.
The installation and adjustment of EWOL propellers are particularly simple and intuitive operations that do not require special technical skills or specific tools, the propellers can be installed and adjusted simply by using a standard wrench and a standard metric Allen key. This can all be done by a trusted mechanic in a few minutes. If you do not have a trusted mechanic or prefer to use a company that is familiar with EWOL propellers, you can find a list of installers in the PARTNERS section of our website.
On the EWOL website in the REQUEST A QUOTE section you can enter your details and the boat’s details, we will get back to you with a detailed quote, if you accept the quote, simply send a confirmation e-mail, and we will send you an order confirmation with the payment details.
Once the order is placed, work will commence the next working day, we will then let you know the production schedule for the ordered propeller model.
EWOL propellers benefit from a unique 3-year warranty on the market, limited to manufacturing defects of the propeller itself, this is a warranty that is unmatched on the market, reflecting the unmatched quality and technology of our products.
An EWOL propeller is an investment that does not lose its value over time, rather it gives greater value to your boat. The materials used are technologically advanced and the interchangeable bushings are an extremely reliable solution over time, allowing you to restore the propeller even after many years of operation, with little expense, anywhere in the world. It is possible to purchase the “SPARE BUSHING KIT” in the SHOP ON-LINE section of the EWOL website.
The competitors’ propellers quickly wear and can only be restored with major costly non-viable interventions on the premises. On the contrary, a set of spare bushings is much less expensive and the replacement does not mean that propeller is sent to the factory, as it can be carried out at a local workshop, in Italy or any remote corner of the planet.
EWOL propellers can be installed on all sailboats, monohulls or multihulls with engines from 15hp up to a maximum of 500hp, whether they have shaft line or sail-drive, in this last case, the propellers are equipped with a FlexDrive anti-shock joint. The maximum axle diameter is 60 mm ISO standard.
There is no problem whatsoever with installing EWOL propellers on boats equipped with a hydraulic inverter, so that the propeller positions itself in the flag position, the propeller shaft must be locked for at least one second. So, it is necessary, with the engine running in forward gear, to turn off the engine so that there is still pressure in the hydraulic circuit, or move slightly in reverse (always while sailing at a speed of at least 3 knots) and then turn the engine off. If this procedure does not work, a device must be installed to brake the propeller shaft (for example, a shaft brake).
From our tests, we found the EWOL propeller provides a sail gain, on variable average between 0.5 knots and 1 knot (depending on the boat, the propeller diameter and other conditions).
EWOL propellers are built using galvanized corrosion-resistant steels, however it is equipped with a zinc anode which aids protection, the zinc anode (or zinc tip) should be changed every year, even if it is not fully worn.
Spare zinc anodes for the EWOL propeller can be purchased directly from our website in the SHOP ON-LINE section or from our partners (dealers and shipyards, etc.), found in the PARTNERS section of our website.
The wear of the support bushings depends on the use of the boat and, therefore, the propeller, if a boat is subjected to continuous use for many days per year, the bushings will probably have to be replaced after 3-4 years, otherwise the replacement can be carried out later on.
There are several possible causes or contributing factors to on-board vibrations, there is not guarantee that the vibrations are caused by a problem with the propeller, here are some of the possible sources of vibration:
– The propeller is a two-blade propeller, this type of propellers are getting noisier than the three-blade models
– The axis has been twisted
– The propeller has a diameter that is too big and passes too close to the hull
– The propeller took a hit and one or more blades were twisted
– The propeller has not been dynamically balanced
– The propeller is partially corroded
– The propeller is hollow
– There are significant deposits or something has become entangled in the propeller
– The tab on the clutch cone of the propeller is too high and pushes the propeller out of the centre of rotation
– The engine under thrust of the propeller touches the engine compartment beyond the silent block
– The engine silent blocks have worn
– The axle stand was damaged or worn
– The rubber bush on the stand has worn out
The solutions to eliminate the causes of vibrations are therefore different, the EWOL propellers are always dynamically balanced, in order to eliminate the possible causes of vibration generated by the propeller.
– L’elica è una due pale, questo tipo di eliche sono sempre più rumorose rispetto ai modelli a tre pale
– L’asse si è stortato
– L’elica ha un diametro troppo grande e passa troppo vicino allo scafo
– L’elica ha preso un colpo e una o più pale si sono stortate
– L’elica non è stata bilanciata dinamicamente
– L’elica è parzialmente corrosa
– L’elica cavita
– Vi sono incrostazioni importanti oppure qualcosa si è impigliato nell’elica
– La linguetta sul cono di innesto dell’elica è troppo alta e spinge l’elica fuori centro di rotazione
– Il motore sotto spinta dell’elica tocca il vano motore al di la del silent block
– I silent block del motore si sono usurati
– Il cavalletto porta-asse si è danneggiato oppure ha preso gioco
– La boccola in gomma sul cavalletto si è usurata
Le soluzioni per eliminare le cause di vibrazioni sono quindi diverse, le eliche EWOL vengono sempre bilanciate dinamicamente, al fine di eliminare le possibili cause di vibrazione generate dall’elica.
EWOL propellers do not require regular maintenance, except to add grease every one or two years. To carry out the greasing, refer to the USE AND MAINTENANCE booklet in the CUSTOMER SERVICE section