Definition Of Full Displacement

[Nomad Willy]

For those that thought this thread was a bit of a mystery and for those still trying to expand their scope on it consider that there are numerous roads to understanding.

When I was in the Navy in electronics school basic electronics was taught using various analogies. For electron flow and resistance current flow was presented to be like water flowing in a pipe and resistance as the narrowing of the pipe or an adjustable valve in-line in the pipe. But the usual method was numerical through formulas and other numerical relationships and mechanics.

For the hull speed questions the same is true. I use numbers a lot for relationships that expand understand but me being a visual person like my mother that was an artist I lean toward visual concepts to relate to complex issues and even the world at large.

The speed/length ratio is expressed numerically and Fish53 relates well to numbers and thus his road to understanding is through numbers. The range of hull designs is identified with fractional limits that relate to wave lengths that a boat creates as she moves through or over the water.

So if you read something that makes you wonder what they’re talking about try another source that will give you a different perspective. The light may go on.

Hope this is heplful.

 

[Art]

For those that thought this thread was a bit of a mystery and for those still trying to expand their scope on it consider that there are numerous roads to understanding.

When I was in the Navy in electronics school basic electronics was taught using various analogies. For electron flow and resistance current flow was presented to be like water flowing in a pipe and resistance as the narrowing of the pipe or an adjustable valve in-line in the pipe. But the usual method was numerical through formulas and other numerical relationships and mechanics.

For the hull speed questions the same is true. I use numbers a lot for relationships that expand understand but me being a visual person like my mother that was an artist I lean toward visual concepts to relate to complex issues and even the world at large.

The speed/length ratio is expressed numerically and Fish53 relates well to numbers and thus his road to understanding is through numbers. The range of hull designs is identified with fractional limits that relate to wave lengths that a boat creates as she moves through or over the water.

So if you read something that makes you wonder what they’re talking about try another source that will give you a different perspective. The light may go on.

Hope this is heplful.

Eric - Well put.

Myself being a [self described] airflow expert [over 45 yrs. hands-on study, learning, planning, building] regarding chimney design, temperature conditions and venturi as well as flex fabric vertical and horizontal tunnel airflow effects... I'd like to mention the following:

Moving items through and movement of and displacement in and separation from-like-kind and rejoining of like kind and capability to enclose or support foreign objects... regarding water and air are not really all that different. In that both have weight and molecules that flow in a fluid/path/state and that both have properties wherein they would rather not be separated; but, if done so will try to immediately rejoin via simplest means/path... unless somehow diverted too faraway so no re-contact capability is afforded. Also in similarity; air and water can join forces with any of the same no matter where they may be introduced for contact. And, both can somewhat alter composition for becoming capable to be mixed together and/or with other liquid or gaseous items.

Like I mentioned: "... water and air are not really all that different."

Hot air balloons at the whim of air currents [with a little assistance from heat torches] can be likened to powerless barges that are at the whim of water flow [awaiting barge assistance]. Dirigibles that have low hp. propulsion engines can be likened to really deep draft FD hulls. Cessna and other privately owned prop planes' speed through air can be likened in similarity to SD hulls. Semi-fast pleasure boats resemble really fast propers - i.e. WWII Spitfire, Mustangs, Zeros etc. Over 100 mph racing boats are not too unlike fighter jets... think Blue Angles.

Point I'm trying to press here: Designs and power-installed of floating or flying units have pretty simple individual criteria regarding their capability of speed, handling, and worthiness in air and/or water. In effect, there is no set [exact] design criterion that connotes fast or slow, nor good or bad handling for any craft. I.e. - each hull-product design and propulsion-scope enabled is extremely individualistic regarding performance capabilities that can be realized.

 

[sunchaser]

Eric

If you'd followed D Gerr over the years, and today go to his website, you'll find that some on TF get more wrought up about this subject than Gerr does.

Look at a few of his and his fellow Westlawn grads' designs. There are hundreds or more . You'll see some real pros in yacht design who have often ventured into the gray areas and built marvelous craft with often barely decipherable by "our" terms hull designs.

 

[Nomad Willy]

Sunchaser,
Great tip I’m sure and I will follow up on that. Can’t bookmark a post but I can put you in “notes”. ¥

Thank you my friend

 

[Nomad Willy]

Art,
Great stuff there mate;
The biggest difference between air and water that I know of is that water is not compressible .. air is. Air brakes and fluid brakes both work but they feel different.
Both tend to follow a curved surface but airfoils and hydrofoils have considerably different chacteristics. Hang gliding and flying ultralight aircraft in addition to my experience w boats gave me opportunities to see these fluids in action and be well aware of many of their differences.