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SPEED TO LENGTH RATIO For a displacement boat, speed is a function of waterline length. The maximum theoretical speed is ordinarily assumed to be 1.34 times the square root of the LWL. Speed to Length Ratio = Velocity in Knots Waterline Length = V LWL
Understanding and calculating marine displacement is essential for the design and operation of ships. This tutorial delves into the formulas and calculations associated with marine displacement, focusing on length, breadth, draft, and block coefficient.
RESISTANCE AND POWERING OF SHIPS. Define effective horsepower (EHP) conceptually and mathematically. State the relationship between velocity and total resistance, and velocity and effective horsepower. Write an equation for total hull resistance as a sum of viscous resistance, wave making resistance and correlation resistance.
Figure 4 shows the impact of sweepback angle on the LCS of a keel for a given taper ratio, where taper ratio is the ratio of the tip chord to the root chord. In the design shown in Figure 1 the sweepback angle is about 400 the taper ratio is 0.53, and aspect ratio is 80 PROFESSIONAL BOATBUILDER.
This template is designed for use with English units. The first set of output computations apply to displacement and semi-displacement vessels. Semi-displacement, or semi-planing, boats normally operate at speed length ratios, V / LWL1/2, from about 1.3 to 1.4 all the way up to about three.
So to convert displacement to cubic meters of sea water, divide the weight in metric tons by 1.025 which is the specific gravity of seawater = volume of displacement in cubic meters of sea water. We raise the volume of displacement to the 2/3rds power to convert it from cubic units to square units.
– Calculate the speed and power for displacement boats by Gerr’s formula. – Calculate power to displacement ratios to the table. – Compare and comment. Kymenlaakso UAS/Terho Halme
