Model Boating Honor

Arts & Crafts

Requirements

  1. Fulfill two of the items below:
    • Buy and assemble a kit for a sailboat 25 to 40 centimeters in length and about 4 to 5 centimeters in width. Maneuver the boat in the water for at least two minutes.
    • Build a miniature boat with an electric motor, from your own design or from a kit (size: 25 to 45 cm in length) and maneuver the boat for three to five minutes.
    • Build a model 45 to 80 centimeters in length from your own design or from a purchased kit. Install a 0.029 or 0.049 internal combustion engine and maneuver it in a race lasting five minutes. Note in writing the characteristics of the model and what you did to improve its performance.

    Answer: Do 2 of the 3: (a) a 25-40 cm sailboat maneuvering for 2 min; (b) a 25-45 cm electric motor boat maneuvering for 3-5 min; (c) a 45-80 cm combustion boat (0.029/0.049) in a 5 min race. — 'Cox 0.049' engines are classics in model boating since 1958 — small 0.8 cc diesel/glow engines used in official races to this day by the MYBA (Model Yacht Brazilian Association); they are light, powerful, and high-revving. Document each model with photos, videos of the maneuver on the water, and the plan/design used for the construction.

  2. Identify and define the following words:
    • Displacement
    • Center of gravity
    • Propulsion level
    • Thrust and buoyancy
    • Single hull
    • Hydraulic power
    • Bow
    • Keel
    • Beam
    • Cavitation
    • Heel (list)
    • Level
    • Dredge

    Answer: 1) Displacement: the weight of the water displaced by the hull, which equals the weight of the floating boat. 2) Center of gravity (CG): the balance point of the model; the lower it is, the more stable. 3) Hull: the external body/structure that floats and gives shape to the vessel. 4) Keel: the lower longitudinal piece of the hull that provides direction and lateral stability. 5) Bow: the front part of the boat. 6) Beam: the greatest width of the hull. 7) Cavitation: the formation of vapor bubbles on the propeller due to low pressure, which reduces thrust. 8) Heel: to lean to one side (to list). 9) Trim: to adjust the balance/trim so the boat sails straight and at the correct waterline. 10) Draft (draught): the depth to which the hull sinks into the water; also the act of dredging/scraping the bottom. — Displacement (Archimedes' principle, 250 BC) is the basis of flotation — a boat floats because it displaces a volume of water with a weight equal to its own; a 100-ton ship displaces 100 m³ of water, balancing buoyancy and gravity. To heel is to lean laterally, to trim is to balance, and draft refers to the submerged depth of the hull.