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The Landing School
Boat Design Coefficients
Below are explanations of the various terms and coefficients used for comparison of boat designs. Designers use them when comparing designs from their own drawing boards and those of other designers. The same info can be used by the layman to assist in selecting a design to build. (from the site)
Design Ratio by Eric Sponberg
A primer on some basic principles of naval architecture for small craft. (from the site)
Engineering the Sailboat - Safety in Numbers
By Eric W. Sponberg, Naval Architect, P.E. (CT). This article was first published in SAIL magazine in June, 1985. Since then, a few improvements or changes in yacht design and engineering have occurred. Therefore, I have modified the article where necessary to bring it up to date. EWS. (from the site)
Heeled athwart ship stability study for a typical sharpie derivative hull shape
The following study and graphic representations (below) examines what the physical attributes are of a flat-bottomed, plumb sided, form stable hull as the boat is heeled through angles progressing from zero through ninety degrees. (from the site)
Motion Comfort Ratio (Ted Brewer)
Motion Comfort Ratio was developed by Boat Designer Ted Brewer. The formula predicts the speed of the upward and downward motion of the boat as it encounters waves and swells. (from the site)
Similtude of Scale
From the online article, Essential Design Data, by Michael Kasten
Talk the talk ...
These definitions are from the Merriam-Webster Online Dictionary and other sources.
1: the act or process of displacing : the state of being displaced
2a : the volume or weight of a fluid (as water) displaced by a floating body (as a ship) of equal weight b : the difference between the initial position of something (as a body or geometric figure) and any later position c : the volume displaced by a piston (as in a pump or an engine) in a single stroke; also : the total volume so displaced by all the pistons in an internal combustion engine (as in an automobile)
a : the indicated quotient of two mathematical expressions b : the relationship in quantity, amount, or size between two or more things
1a : a long piece of heavy often squared timber suitable for use in construction b : a wood or metal cylinder in a loom on which the warp is wound c : the part of a plow to which handles, standard, and coulter are attached d : the bar of a balance from which scales hang e : one of the principal horizontal supporting members (as of a building or ship) ; also : boom, spar
a : the tendency of a body to float or to rise when submerged in a fluid b : the power of a fluid to exert an upward force on a body placed in it; also : the upward force exerted
Pounds per inch immersion: the weight required to sink the vessel one inch in the water.
Center of Buoyancy
•Centre of Buoyancy is the center of the gravity of the volume of water which a hull displaces
Buoyancy and Stability
Buoyancy is generally understood to be that property of a body that enables it to float on the surface of a liquid or in a fluid. (from the site)
Roger Long, a former researcher for the USCG, has developed a basic information site on various angles of stability.