Articles (Page 1) - The Propeller Pages
Advantages of Certifying a Propeller
By Janett Hernández, Degree in Information Technology
Certification agencies are governed by the compliance of specific sets of standards; due to this, manufacturers should meet said requirements, and ensure that the product is in compliance with the established standards. Hence, the concept of a certified product: one that has been proven ...
Advantages to Pre-heating before welding
By David Rivas, Mechatronics Engineer and Informatics Technician
Much of the repair work made to a partially-damaged propeller includes the welding process; however, we would like to emphasize the importance of applying
heat before welding, to reduce post-weld damage.
Solder cracking and cracking at solder joints are common defects resulting fr ...
Taper Charts and How to measure propeller taper bores
Using digital or vernier callipers ;-
Measure the small end to the taper bore - nut end I.D. (inside diameter)
Measure the large end to the taper bore - forward I.D.
Measure the overall length of the propeller hub (boss)
Measure the keyway width and height.
Measure the overhang distance at the nut end (draw) with the propeller tightened on the ...
Sources of Energy Inefficiency
By Manuel Paez
In addressing the problem of energy efficiency it is useful to understand
just where the energy is expended in a fishing vessel and what aspects of this
can be influenced by the operator, boatbuilder or mechanic.
In a small slow-speed vessel, the approximate distribution of energy created
from the burning of fuel is shown in fig ...
Propeller Sizing - Have You got the Correct Propeller?
by Robert Olds
With high fuel prices, now is a good time to fit the best propeller.
The first step in assessing whether an installed propeller is suited to the
vessel and engine is observation. Does the vessel perform as well as others
of similar power and design? If the answer is no, it is important not to
jump to the conclusion that the p ...
Manual Procedure for Propeller Pitch Measurement
by Ramses Herrera
Based on a request from one of our clients in Ecuador, we elaborated a simple procedure to measure a propeller's pitch.
Necessary equipment to perform it:
Protractor (angle measurement)
Plumb Line (not necessary on small props)
What is Propeller Pitch?
By Edgar Reyes.
A propeller can be defined as follows: A mechanical device formed by two or more blades that spin around a shaft and produces a propelling force in boats (or airplanes).
There are several technical terms to define the propeller's characteristics such as: diameter, pitch, disc area relation, hub, bore etc. All these characteristics ...
There are several different kind of propulsion systems as much as applications, a lot of research has been made to try to get the most efficient system in order to lower operation costs (fuel consumption) without sacrificing performance and life of the vessel. Attempts of radical designs have been made without re ...
Do Propellers Sing?
Yes, sometimes they sing: Some propellers in service produce a high-pitched noise, often referred to as Singing. This sound typically is a clear harmonic tone much like a humming or ringing wine glass.
More of an annoyance than anything harmful, the causes of singing are not completely understood. Many theories have been put forward to account for ...
Conversion Advantages of an Open Propeller into a Propeller-Nozzle System
The conversion of an Open Controllable Pitch Propeller into a Rice Propeller-Nozzle System has its advantages, such as: the increase of velocity (10-20%) and bollard pull (20-35%) which summarizes in fuel savings that goes from 8 to 12%.
For such effect, Ka-Speed blades that adjust to the nozzle replace the ...
The primary function of any marine engineering plant is to convert the chemical energy of fuel into useful work and to use that work in the propulsion of the ship. A propulsion unit consists of the machinery, equipment and controls that are mechanically, electrically, or hydraulically connected to a propulsion shaft. After reading this chapter, yo ...
Number of Blades
The choice of the number of blades is one of the first decisions to be made in the design of a screw propeller.
Marine screw propellers usually have 3, 4 or 5 blades, of which four blades are the most common.
Two-bladed propellers are used on sailing ships with auxiliary power, as they offer the lower resistance when in the sailing condition.
Tolerances for the manufacture of propellers
area of the propulsion many applications exist, that they go from crafts
of fishing, of pleasure, of load and of speed between many other's.
It's for that reason that a classification of
propeller's exists that determine the tolerances that it should have a
propeller, according to the necessities of a craft.
The ISO 484/ 2-1 ...
Properties of Bronze for Marine Propellers
COMPARATIVE SERVICE DATA. The superiority of
nickel aluminum bronze has been convincingly demonstrated by an
One propeller of each material was installed on
a 6,000 ton twin screw carrier, which subjects its wheels to unusually
severe service by operating on the Orinoco River in Venezuela.
The sand bars a ...
Technically, corrosion is the attack and progressive destructions of a
metal by means of a chemical action. Galvanic corrosion, which is
characterized by its destructive power, comes from an electrolysis
phenomenon between two metals of different electrical potential that is
in contact and in the presence of humidity.
Between the meta ...
Maganese - Nickel Aluminum Bronze (Aqualloy) vs. Stainless Steel in Marine Propellers
The superiority of Mn - Ni Al bronze
(Aqualloy) has been convincingly demonstrated by its characteristics of service,
in which has been demonstrated to be the good enough, for the work in marine
The consumption of use (Aqualloy)
bronze has increased quickly in the United States, and other countries itís
their property of being no ...