The Importance of Appropriate Pitch
Those who are new to the sports of fishing or leisure boating may be surprised to learn that one of the most important characteristics of a propeller is its “pitch.” Even though the term sounds to novices far more akin to baseball than to boating, it is quite an apt word. Just as a thrower’s pitch causes the ball to be propelled forward, so too does propeller pitch provide information about forward motion. In the case of prop pitch, the term refers to the distance that the propeller could be expected to move forward because of one full revolution of the blades if conditions were ideal.
Pitch, as stated in propeller specifications, refers to a theoretical distance. This is because conditions in the real world are rarely ideal. The vagaries of weather and water conditions will normally mean that propeller pitch as actually experienced will usually be less than the pitch number advertised for that propeller.
Many boaters have misconceptions about propeller pitch. They may think that a larger pitch number is always preferable since it will mean that the propeller, and hence the boat, moves forward more in a single revolution. This in turn, they believe, will make the boat able to go faster. The truth, however, is that every motor has a limit. Using a propeller with a pitch that is too large will only stress the motor, causing the boat to go slower. It can also cause a dependable engine to wear out long before its time.
Outboard Propellers and the Issue of Vibration
When it comes to having a look at the various outboard boat props on sale today, boating enthusiasts will find that they have several major categories from which to choose. Outboard propellers may consist of Apollo Stainless Steel Propellers, Ballistic Stainless Steel Propellers, Vortex Aluminum Propellers, or Michigan Match Propellers. Among these various kinds of outboard propellers, boaters can find virtually any combination needed of pitch and diameter in both right handed and left handed rotations.
When to Replace an Outboard Propeller: The Vibration Issue
Many boaters are not completely clear on the issue of when they need to replace a propeller. In some situations, of course, the need to purchase a replacement propeller is beyond doubt. If the propeller shows visible signs of wear such as cracking, chipping, or warping it must be replaced. To continue with the propeller in that state is inadvisable from a performance and fuel economy standpoint, and from a safety perspective.
What if, however, the outboard motor seems to be vibrating a great deal when this has not typically been true of your system? In this case, if the propeller looks as good as new, or very nearly so, boaters may conclude that the problem must not lie with the propeller. This, however, could be a misjudgment. In many cases, damage to the blades of a propeller is not visible to the naked eye. Blades may be bent slightly out of true, in which case the propeller should be replaced.
Boat Propellers: Energy Efficiency Considerations
Boaters interested in purchasing Johnson boat props may be eager to learn about the ways in which propeller characteristics and a boat’s operator can influence the energy efficiency – and fuel consumption – of a marine propulsion system. In the typical small boat, not all of the energy generated by the motor ends up reaching the propeller. In fact, only about 30% of the generated energy makes it to the propeller.
The energy not directed into Johnson boat propellers goes to a variety of other uses, such as counteracting the resistance of wave motion, overcoming the friction atop the surface of the water, and minimizing resistance emanating from the boat’s wake.
When it comes to Johnson boat propellers, two major factors control how much energy is wasted as the propeller turns. The boat operator can control the first factor only at the time of purchase. This is because propeller design itself can have a large influence on fuel efficiency. Operators need to make sure that the propeller they choose is appropriate for the motor that it needs to work with, as well as appropriate for the type of boating activity the owner has in mind.
The second major factor that influences energy efficiency for propellers is an ongoing rather than a one-time concern. The way in which a boat operator uses the propulsion system can add to or detract from fuel efficiencies, as can issues such as proper maintenance of the hull.
The Need for Aftermarket Boat Props
Those who are new to the leisure activity of boating may not be aware of one key fact about outboard propeller engines. In most cases, the propeller that ships with an outboard engine is a “stock” part and is not, in fact, the ideal propeller for every boat that may elect to include that particular type and model of outboard motor. Stock boat propellers such as these tend to be designed along “compromise” principles that will allow the motor to be used with a large number of different boats.
Depending on the hull and load that the motor must eventually contend with, however, these boat props may range in performance from average to unsatisfactory. The solution to this problem is to look at the range and variety of aftermarket boat propellers instead. Choosing the correct propeller for a specific boat and engine will allow the engine to run properly at its rated horsepower, which is usually marked clearly on the engine cover.
Outboard engines are supposed to be able to run at their maximum rated revolutions per minute – this situation creates peak efficiencies. The wrong propeller can cause an engine to run at an exceptionally high RPM. This leads to faster wear and tear on engine parts because it creates additional friction. Too few revolutions per minute are also inadvisable since it causes carbon build-up as well as poor fuel utilization. The right boat propeller, however, can help boaters to avoid both of these situations so that they can derive maximum use and pleasure out of their watercraft.
Michigan Wheel Propellers
Boaters know the importance of boat propellers. No one wants a sub-par product, and no one wants to be stranded without the necessary gear when something inevitably goes wrong. If you are looking for a new propeller or you simply want to find a product to keep as a spare, it is important to find a product made by the right company. As such, it is always wise to go with a well-known name like Michigan Wheel for your boat propeller needs.
It is always important to look for boating products from a company that you can trust. Michigan Wheel is not new to the game of manufacturing top of the line boating goods, and it continues to innovate in the market. Unlike some companies, Michigan Wheel is not content to merely manufacture one great set of boat propellers and call it a day – instead, the company continues to find ways to stay relevant in an always changing market. Today’s boat propellers are far superior to those available in years past, and one can always count on the company to find ways to surpass even the best boat propellers on today’s market.
Michigan Wheel has long been one of the standard names in inboard boat propellers, creating several models of propellers for both commercial and consumer boats for over one hundred years. The boat propellers themselves are divided into several different classes, each perfect for use in different waterborne craft. Whether you need an inboard propeller for your sailboat or for a towboat, Michigan Wheel has the model to suit your needs. Each of these devices are made to the company’s exacting standards, made of quality materials and with the ability to withstand the rigors of repeated use. Michigan Wheel stands by each of these products, and the company’s global recognition speaks for their quality.
In addition to the inboard models, Michigan Wheel also has a number of outboard boat propellers. Like their inboard cousins, these models are made to the company’s exacting standards. These products are accurate and consistent, perfect for use as both spare boat propellers and as replacements for existing models. Michigan Wheel’s products can be used in many different circumstances, and there are boat propellers available for the budget of almost any boater. Whether you need a simple back-up or your are looking for something at the top of the line, there is a product available to suit your needs.
Whether you are looking for an inboard or outboard model, Michigan Wheel has the boat propellers that you need. They are constantly innovating in the market, and their long-time work in the industry can assure you that any product that you choose to purchase will be of high quality. If you need a replacement or merely wish to upgrade to something that is a bit better than what you have had in the past, you may want to take a look at one of the company’s many products. At the end of the day, choosing one of Michigan Wheels fine propellers is a great way to know that you will get to where you are going.
Lowdown on Volvo Penta Propellers
When choosing a boat propeller most people concentrate on the diameter and pitch and while these are important there are other factors to consider when looking for a good propeller that will be sturdy, give good performance and maximize engine performance. Volvo Penta propellers have been known for decades as some of the finest propellers for discerning boaters. Over a year of design work goes into the creation of each Volvo Penta propeller and their current line of propellers have options for every type of boat and any application or use.
Volvo Penta propellers come in 3 and 4 blade options as well as 2 blade options for smaller boats with engines ranging from 5hp up to 40hp. Volvo Penta also makes a unique folding blade for sailboats that reduces drag by up to 8 times compared to fixed 3 blade propellers when under sail. Materials available include stainless steel, aluminum and a nickel-aluminum-bronze alloy to retard growth and for excellent corrosion resistance. Both cupped and raked blades are available for high speed applications and superior lift.
Perhaps the most interesting offering is the Volvo Penta Duoprop, a dual propeller solution with twin counter rotating propellers. The Duoprop was introduced in 1982 and has been a revolutionary design in the boating industry. Volvo Penta Duoprop propellers provide several benefits including:
- Faster acceleration by up to 30% versus single propellers
- Lowers fuel consumption by 10-12%
- Faster planing
- Lower vibration and noise levels
- Better maneuverability in all situations because the dual props put all their energy into moving the boat forward, unlike conventional single propellers which have to fight lateral forces
You and your boating pleasure deserve the best and the engineers at Volvo Penta have designed their propellers to provide the best performance no matter what type of boating or sailing you do. Perfecting standards in manufacture ensure reliable performance from every Volvo Penta propellers and since Volvo Penta propellers are perfectly matched to engine characteristics and drive hydrodynamics you will get the best fuel efficiency and maximum efficiency from every type of Volvo Penta propeller. Plus all Volvo Penta propellers come with 1 year warranty to be free from defects in materials or workmanship. All things together, Volvo Penta is a company built on history, tradition, technology and Eco-friendliness that works to give each and every boater a great experience with their propellers through rigorous research, design and testing.
Outboard Propellers 101
Once you have the outboard motor for your boat it is important that you choose the right outboard propeller as well. The propeller should be suitable for the type of boating that you plan to do, different props are available for shallow draft boating, for water skiing, trolling and for other types of boating. You also need to make certain that the prop will allow the engine to reach the manufacturers recommended RPM’s when at full throttle or you risk damaging your propeller and engine. Choosing the right propellers is critical for the performance of your boat and for your boating enjoyment.
Boat propellers are often described by their diameter and pitch. The larger your engine is in horsepower, the larger diameter prop you will generally want. The pitch describes how far the propeller advances with each revolution. A lower pitch gives better pulling power, however if you use a propeller with a pitch that is too low you won’t be using all the power of your engine. A higher pitch allows the boat to go faster, but this is only true if you have enough horsepower to keep the RPM’s at the optimum range. A pitch that is too large makes the propeller heavy and it demands more power than the engine can provide.
After determining the proper diameter and pitch you need to consider how many blades to have on your prop. Outboard propellers typically come with either 3 or 4 blades. Unless you are running a high horsepower motor or using the boat for bass fishing, you will most likely want to choose a 3 blade propeller. 4 blade propellers are designed more for high speed usage with less steering torque and vibration at high speeds. Water skiers can also benefit from using a 4 blade propeller.
The next thing to consider is the construction material of the propeller. Outboard propellers can be made from aluminum, stainless steel, or composites. Aluminum is the most common choice for the manufacturer’s stock factory equipment. They are inexpensive and easy to repair and they work well in a wide range of applications. Stainless steel propellers are more expensive, but they are also more durable and less likely to suffer damage. Composite propellers are typically only utilized on very small horsepower applications, and are not nearly as popular as aluminum and stainless propellers.
Your main goal when choosing a propeller is to ensure that it allows the engine to perform optimally at wide open throttle. Boat dealers and Prop Shops can provide you with formulas to determine the proper pitch, diameter and number of blades based on your engines power or horsepower.
Changing Your Propeller
Boating enthusiasts know that for all the wonderful times and adventures they have on their water craft, there is also a maintenance aspect that must be considered. One periodic task that must be taken care of is changing out an old propeller for a new one. This is not a frequent job; it needs to be done only when the existing propeller shows serious signs of wear or when it has been subject to an accident or some kind of malfunction. Of course, some boaters also change their propellers simply to get better performance from their water craft.
Boat Propeller Pullers: A Handy Tool
The most useful tools a boater could have in this situation include boat propeller pullers. With such a tool, the task of removing the old propeller becomes much simpler.
How to Use a Boat Prop Puller
Using boat prop pullers is not difficult, but for the job to go well, it requires a little advance planning. First, take a pencil and use it to mark where the old propeller lies in the propulsion system. You will use this mark later to make sure that the new propeller is seated in exactly the same location.
After that it is time to get the old propeller ready to remove. The first step is to turn the propeller slowly while you hold on to a ratchet around the retaining nut. Do not loosen the nut 100 per cent of the way. When the propeller is loose, it is time to use the prop puller, which is used to remove the existing propeller from the shaft it normally sits on.
Understanding Pitch and Slip
Pitch is becoming an increasingly familiar term to boating enthusiasts interested in purchasing aftermarket outboard propellers for their watercraft. Usually defined as the distance a propeller will move through a soft medium such a balsa wood after one full turn of the blades, pitch is an idealized figure that is rarely seen in actual use of outboard boat props.
Boaters, therefore, might question the purpose of a pitch specification for a given propeller. If the prop is advertised as offering 13 inches of pitch, but this is a theoretical number, what can a boater expect in terms of real world performance?
Fortunately, there is another term that helps to clear up this conundrum: slip. When it comes to outboard boat propellers, the word “slip” gives the difference between the theoretical and the actual. That is, slip describes the degree to which a given propeller usually achieves its stated pitch. A propeller that is properly installed and appropriate for both motor and boat can usually achieve as much as 90 percent of “perfect pitch,” though in some cases a figure closer to 80 percent is more realistic.
Why Not Just Scale Down Pitch Numbers?
The concept of slip usually raises a simple question: why do propeller manufacturers use idealized pitch numbers in the first place? Why not just multiply ideal pitch by 80 or 90% and use that figure as the pitch? The answer to this lies in the complexity of watercraft usage. Boats will achieve closer to their ideal pitch when conditions are optimal. Slip, therefore, depends on context whereas pitch values remain constant.
Propeller Terms: The Intricacies of Exhaust
Even an absolute newcomer to the sport of pleasure boating begins with a basic understanding of engine exhaust, but it may come as a surprise to some that outboard boat props actually have several ways of releasing or venting the exhaust produced by the motor. One of the most common arrangements is through “hub exhaust.” These propellers have blades attached to a hollow barrel through which exhaust can pass. This allows exhaust to avoid contacting the blades directly, which improves the way water flows onto the blades.
Another arrangement is “non-through hub exhaust.” As one might expect, in this system there are not any holes for exhaust near the shaft of the propeller. These systems are most commonly found on stern drive motors with low horsepower and on some low horsepower outboard motors.
Still other outboard propellers use a system known as “over the hub exhaust.” In this arrangement, blades are directly affixed to a small tube that runs near the propeller shaft. This eliminates a large exhaust tube. Over the hub exhaust systems are often employed when boating enthusiasts want to reach the maximum possible top speed of their motor.
The final system commonly employed is termed “over/through hub exhaust.” This is a combination arrangement that uses features from both the over-hub and through-hub systems.
Since outboard props can use a variety of exhaust systems, the boater determined to get superior performance should carefully consider which system would best suit his watercraft and his needs.