MUN SailingIntroduction to Sailing Theory

Instructional Session #1

With: Daniel Rees

Lesson Outline:1.) Anatomy of a Sailboat

2.) Bernoulli Principle

3.) Points of Sail

4.) Tacking & Gybing

5.) The Principles of Wind

6.) Classifying & Identifying Wind

Anatomy of a Sailboat 1.) Sail Area 2.) Keel/Daggerboard/Centreboard 3.) Rudder 4.) Hull 5.) Rigging

Centre of Effort (CE)- Sail Area

Centre of Lateral Resistance (CLR)- Keel/Daggerboard/Centreboard- Rudder- Hull

Bernoulli Principle

- Like an airplane foil, sails allow a vessel to generate lift.

- When lift is countered by the resistant forces of the boat (CLR) it converts the lift into thrust and allows sailboats to move forward.

Key TermsLift: Result of the Bernoulli Principle and high/low pressure systems on a foil.

Thrust: The force of a sailboat to move forward through the water. Is a result of the power of the wind as it generates lift and is countered by drag.

Resistance/Drag: The force the boat meets as it pushes water aside (Displacement Hull). Is coupled with lift to produce thrust. Without resistance a boat would slide-slip endlessly.

Buoyancy: Keeps the boat up in the water (Positive, Neutral, Negative). Equivalent to force of gravity on airplanes.

Forces of Sailing

Foils: Endless Possibilities!Airfoils: - Like a sail

Hydrofoils: - Like a sail – but underwater. - Use the principles of water to create high/low pressure systems.

https://www.youtube.com/watch?v=5doBIv3TVbA

Points of Sail

Getting ThereTacking: Change of the boat’s sailing angle, such that the bow passes through the wind.

Gybing: Change of the boat’s sailing angle, such that the stern passes through the wind.

Short Tacks vs. Long Tacks- Banging a Corner.- Beating it.

What are the advantages + what are the disadvantages?

Tacking TacticsThings to Consider:

- Energy Conservation

- Wind Shifts (Knock or Lift?)

- Sail Trim (Boat Maintenance)

- Tides

- Geographic Limitations

- Other vessels

Wind Shifts• Knock/Header: A wind shift that pushes your sailing angle away

from your desired position. Dependent on the situation, it may be better to tack over.

• Lift: A wind shift that favors your sailing angle and lets you sail at a closer angle to your desired position. Adjust bearing and sail on!

“A bad wind blows someone good.” – Nan Chaytor

- A knock on one tack is a lift on another!

Wind Shadows

Geographic Wind Shadows

Wind Shadows

Opponent Boat Wind Shadow

“Dirty Air”

“Covering”

LOLZ

Wind ChannelsGeographic

Wind Channels

Fjord of Norway

High Pressure Zones

Beaufort Wind Scale

Identifying Wind Direction• Flags• Smoke• Cloud Movement• Waves• Wind Indicator• Sound in your ears• Grass Flick• Check your sails

DO NOT LICK YOUR FINGER -ewww

Questions?

Thanks for hanging out with us!