Another important part of your vessel that is relatively easy to inspect is your propeller(s). If you are outboard powered or stern driven, you likely have the luxury of being able to see your props anytime the engines or drives are tilted up. With conventional or pod drives viewing your props will require the vessel to be out of the water. Either way, take advantage of the opportunity to inspect them whenever possible. It doesn’t take much, surprisingly little actually, to reduce the efficiency of your propeller(s) and with fuel prices now around $2 per litre, efficiency is more important then ever!
With the floating debris we have in our waters it is not hard to hit something with a propeller. Sometimes that can happen without us noticing. The result can often be some amount of damage to a propeller. Even if the damage is minimal, fuel economy will suffer more than you would expect. Another enemy to efficiency is organic growth. Recreational vessels spend much time sitting unused and that is when organic growth happens. Most understand that a ‘dirty’ hull will create increased fuel consumption but many of us don’t realize how ‘expensive’ dirty propellers can be.
The bottom line is that it pays to keep your propeller(s) ship-shape.
Inspecting a propeller can be as simple as visually checking for any imperfections and running your hands along the blade edges, feeling for anything that isn’t smooth. A few small wrinkles or chips can easily cost you 10% in fuel economy. Wear gloves to protect your fingers. Chipped or bent edges of propeller blades affects the propeller’s balance. Propellers need to be balanced, like the tires on your car, or they will cause vibrations in the drive. Over time these vibrations can wear out propshaft seals or cutlass bearings, leading to expensive repairs. Upon inspection, if a propeller has any damage, make arrangements to have it removed and repaired. Having a spare propeller ready and waiting in good condition will allow the vessel to be returned to service without having to wait for the repair. Carrying spare(s) is highly recommended for several reasons.
Keeping organic growth off your propellers is a business onto it’s own. There are several ways to achieve this. One method is to utilize a coating and there are several types of coatings, with another method utilizing ultrasonic waves. Sonihull and Hull Shield are two examples of ultrasonic antifouling systems. Coatings fall into two general categories, anti-fouling and foul release. Propspeed is an example of foul release coating. Foul Release coating is so smooth that growth cannot adhere to the surface and if it does, the grip is tenuous enough that when the propeller starts turning, the water washes the growth off leaving a smooth clean (and efficient) surface behind. The other type of coating is an anti-fouling paint. These paints are typically concentrated with zinc. Zinc has two benefits, it inhibits growth and it acts as a sacrificial anode for corrosion protection.
Ultrasonic antifouling has several benefits, there are no paints or coatings required and the effectiveness doesn’t wear off or diminish over time. The vessel does require power for the system, unlike a coating. Ultrasonic systems can be installed to inhibit growth on the hull as well as the drives. The installation will be a four figure cost and is dependant on the size of the vessel but this is a one time investment, not an annual charge.
Foul release coatings are quite expensive (often into four figures) so proper application for durability is key. When properly applied these coatings can last two, maybe three years. Proper application is key and it is not simple. For most it is not a DIY project but can be done if you have the right skills and shop setting. The materials are several hundred dollars, even for only one large propeller.
Anti fouling paint is not as durable but is far less expensive. A spray can costs between $30 and $50 depending on the brand and a can of matching thinner/cleaner is about the same. One can will paint several propellers. Cleaning and painting the propeller(s) is an easy DIY project, especially when compared to the foul release coating process.
Which ever method is chosen, the goal is to keep your propellers as clean and efficient as possible. If you have more questions than this propeller post has answered, send us an note and I’ll get back to you.