Hull Roughness and its Effects on Planing Boat Performance

2021 ◽  
Author(s):  
John C. Daidola
Keyword(s):  
Antifouling Paint ◽  
Constant Power ◽  
Roughness Profile ◽  
Hull Structure

The effects of hull roughness on loss of speed at constant power are investigated. Vessel lifetime roughness profiles are postulated based on construction, coatings and maintenance. These are utilized to determine loss of speed and change in running attitude for planing boats. The formulations are directly applicable to any planing boat for which a lifetime roughness profile is constructed as presented. The approach to developing the speed/power predictions and the roughness profile is provided. This approach can be utilized to analyze the effects of roughness due to hull material utilized and quality of construction, roughness from paints and coatings and their method of application as well as damage to the coating during maintenance, deterioration of the hull structure material, as well as biofouling influenced by the type of antifouling paint or coating and method of application. It provides a means for investigating different magnitudes and scenarios of these causes of roughness rather than providing only example results.

THERMAL LOAD EFFECTS ON ALUMINUM LIGHT ALLOY PLATES WITH EPOXY COATINGS

2017 ◽  
Vol 159 (B2) ◽  
Author(s):  
D Boote ◽  
T Pais ◽  
G M Vergassola ◽  
D Giannarelli
Keyword(s):  
Solar Radiation ◽  
Surface Finishing ◽  
Light Alloy ◽  
Hull Structure ◽  
Dark Colour ◽  
Influence Of Temperature On ◽  
Load Effects ◽  
Surface Distortions ◽  
Stress And Strain Distribution

When the assembling of hull structure is completed, the sides of metal motor yachts are usually affected by bumps and hollows coming from welding plates to each other and plates to frames. These defects, normally tolerated on merchant ships, cannot be accepted on superyachts for which the external surface must be smooth and glossy. For this reason the surface finishing is achieved by a long and delicate process of filling, fairing and painting. The final result of this process is very important for the yacht aesthetics as the general appearance of the vessel depends on the external painting. As a matter of fact the quality of painting depends mainly on the undercoat preparation to assure an adequate grip and, most of all, a perfect smooth and faired surface. Despite accurate preparation and painting, surface conditions can undergo undesired alteration because of excessive heating due, as an example, to a long exposure to solar radiation. While stresses do not reach significant values because of the relatively low intensity of thermal loads, strains could still cause very slight surface distortions and undulations which are perceived by human eye as a surface defect. The phenomenon becomes particularly evident if the surface is painted with a dark colour. In this paper an investigation on the influence of temperature on the stress and strain distribution of aluminium light alloy plates coated by filler layers of different kind and thickness is reported. The study has been performed by FEM structural analyses calibrated by experimental measurements performed on laboratory specimens. This work represents the continuation of a research begun some time ago with the measurement of temperatures on yacht hulls exposed to solar radiation in different conditions.

On the Evaluation Method of Wavelet Analysis for Surface Roughness

2010 ◽  
Vol 44-47 ◽  
pp. 4077-4080
Author(s):  
Mei Fa Huang ◽  
Xiong Cheng ◽  
Bing Kuang ◽  
Jiang Tai Huang
Keyword(s):  
Surface Roughness ◽  
Wavelet Analysis ◽  
Surface Topography ◽  
Evaluation Method ◽  
Surface Profile ◽  
Experimental Results ◽  
Roughness Profile ◽  
Mallat Algorithm ◽  
New Generation

The quality of workpiece is influenced by the surface roughness. However, the assessment of parameters of surface roughness is not researched intensively in the new generation GPS standards system. This paper presents a method to assess parameters of surface roughness. The methodology adopts wavelet analysis to construct the model of surface topography and uses the mallat algorithm to separate roughness profile from surface topography. The assessment results of surface profile are calculated according to the standard ISO 4287:1997. The experimental results show that the method not only avoids simplicity the assessment of parameters, but also decreases the number of productions of mis-acceptance and mis-rejection.

Thickness and Fiber Content Optimization in VARTM Method for High Speed Craft

2013 ◽  
Vol 789 ◽  
pp. 412-416 ◽  
Author(s):  
Sunaryo ◽  
Gerry Liston Putra ◽  
Sri Maharani Lestari
Keyword(s):  
High Speed ◽  
Production Efficiency ◽  
High Strength ◽  
Fiber Content ◽  
Optimum Number ◽  
Material Efficiency ◽  
Hull Structure ◽  
The Matrix ◽  
Improve Production Efficiency

To improve production efficiency and quality of fiber-glass boatyards many research have been done both through technological as well as management aspects. One of these developments is Vacuum Assisted Resin Transfer Molding (VARTM) which is claimed to have high strength and material efficiency. This method has not much been applied in Indonesian boatyards, most of them are still using conventional hand lay-up. The research is aimed to investigate the strength of the composite and the optimum amount of materials to obtain the required strength for its application on boat buildings. Experimental approach was conducted in the research using 800 biaxial and 900 unidirectional E-glass for reinforcement, and vinylester (RIPOXY R-802-EX-1) resin for the matrix. The ultimate tensile strength and Youngs modulus of the composites are obtained through tensile and flexural test based on ASTM D 3039 and ASTM D 790 standards. The data obtained are used to determine the optimum number of layers and fiber content on certain locations of the boat hull structure in order to comply with the requirements of classification rules.

scholarly journals Power quality issues: Power supply interruptions as key constraint to development in Ekiti State, Nigeria

2021 ◽  
Vol 7 (3) ◽  
pp. 109-117
Author(s):  
Adeoye OS
Keyword(s):  
Power Quality ◽  
Power Supply ◽  
The State ◽  
Constant Power ◽  
Transformer Substation ◽  
Distribution Company ◽  
Quality Issues ◽  
Set Up ◽  
Supply Interruptions

The power quality issues in the world today are critical to the development of different nations. Prosperity of each nation depends on availability of constant power supply and the quality of supply of power is very important to the required developments in world in the past, the present and the future. Constant power supply is a major challenge in Africa particularly in Nigeria where the generated power is less than thirty percent of the required power. The metrics of power quality are voltage sag, flickers, spikes, harmonics, notching, transients and interruptions. This paper reviewed power quality issues and the interruptions as they affect the development of the State. The level of interruptions in Ekiti State was thoroughly examined and the causes of power interruption in the State were investigated. The method used was the collection of data in respect of power interruptions on Ekiti feeders from the Benin distribution company, assessment of the collected data through simple programming as a command for plotting the graphs through the use of MATLAB 2015 depicting the behavioural pattern of the interruption for a period of six months in 2016. The result shows that the interrelationship between the interruptions and development particularly as it affects domestic consumers, small and medium scale enterprise adversely. Recommendations were suggested with the objective of solving the problems being set up by interruptions in the State and these include installation of reactors, automatic voltage regulators and effective tap changing system on the lines, busses and transformer substation respectively.

Sign in / Sign up

Export Citation Format

Share Document