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Outboard motor vs inboard5/25/2023 Pro and contra wheel effect: besides negative characteristics, it can also help maneuvering Reversing the motors usually involves loads on the motor and a time delay controllable pitch propellers and gearboxes for reversing are expensive. In addition, for this type of drive to change the direction of rotation, known as reversing, either the motor itself or the gearbox must be reversible, or the propeller must be a controllable pitch propeller. The disadvantages of shaft systems include the fact that they (usually) do not contain any maneuvering elements, such as a rudder, and sometimes have a very pronounced wheel effect. Finally, shaft systems also have relatively low service and maintenance costs. Another advantage: a balance in the ship, since with shaft drives the position of the motors can be variably determined (for example, by adjusting the shaft length accordingly). Advantages of the shaft system: the systems are simple in design, easy to maintain and inexpensiveĪdvantages: the systems are mostly simple in design, well laid out, easy to maintain, and relatively inexpensive compared to other propulsion systems. In addition, the gearboxes often have other outputs to drive generators or pumps for example, powerful hydraulic pumps are required to operate the stabilizers bow and stern thrusters must also be supplied. These serve to reduce the engine speed to achieve specific speeds for favorable drive efficiency. Gearboxes are often part of the shaft system. In limited space conditions, a gearbox may also serve to compensate for angular and/or vertical misalignment. Normally, a shaft train consists of a straight line from the engine flywheel to the propeller. The rear bearing, called the stern tube bearing, is sealed from seawater by a stern tube seal, such as a stuffing box. In shaft drives, the actual shaft is held by bearings. Gearboxes are often part of shaft systems – important for reducing speeds At the end of the shaft, the drive shaft is deflected at right angles and emerges horizontally from the shaft. Rubber sleeves are fitted between the shaft and the hull to seal the hull. In recreational marine applications, the shaft device is divided into three different designs: L-drive – the inboard engine transmits its power directly aft via the drive shaft to the propeller, possibly via a gearbox, V-drive – the inboard engine transmits its power with a first drive shaft forward to a reversing gearbox and from there aft to the propeller.Ī special feature is the saildrive – a compact system used on motor and sailing yachts with low propulsive power: from the engine, which is installed in the hull of the yacht, a permanently flanged shaft with a drive shaft (propeller shaft) leads vertically downward and exits at an opening in the hull. The marine shaft device may initially consist of one or more parallel drive trains. The shaft system is the classic propulsion system for recreational vessels, there are three designs The so-called propeller nacelles for large vessels (pods) also play no role here, with the exception of Volvo Penta’s smaller IPS system for recreational boating. The term shaft system has only come into use since other types of propulsion, such as sterndrives, jet drives and outboard motors (the latter two will not be discussed in detail here), have been used in yachts and it has become necessary to differentiate between the various propulsion systems. Only about one percent of the transmitted power is lost in the form of bearing heat, it is said with single gear units, the losses are still very low at two to three percent. The advantages are obvious: for the most part, the system is relatively manageable, and the direct transmission of turning power ensures that very little power loss occurs. Many yachts are still equipped with shaft systems today. The classic: the shaft – little power loss, but reversing and wheel effect We present three of the most important types of propulsion and describe advantages and disadvantages. What are the advantages of shaft systems, so-called sterndrives and a pod, specifically: the IPS system from Volvo Penta? SeaHelp gives an overview.Īnyone who wants to move on the water under motor, can not avoid a few thoughts about the type of drive of the particular motor yacht (or the built-in machine for sailing yachts). In addition to the size of the yacht, the type of use and performance, the buyer should also consider the various types of drive available on the market before making the purchase in order to avoid disappointment later on. Whoever wants to buy a motor yacht is often faced with the choice of the right drive.
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