Southwest Educational Development Laboratory

Classroom Compass
Volume 2 Number 3
Summer 1996


Power Boat Design

A Design Exploration for Upper Level Students

New initiatives in design and technology can influence school staff collaboration. This activity, Power Boat Design, is excerpted from a unit presented in Technology Science Mathematics (TSM) Connection Activities, a curriculum of integrated design projects for grades 6 and up, published by Glencoe/McGraw Hill.

This design project brings together science, mathematics, and technology, allowing in-depth exploration of design principles and the underlying mathematics and science that support them. Science units on buoyancy, Newton's Laws of Motion, and Archimedes' Principle are relevant to the boat's design and function. In mathematics, students need an understanding of surface area, volume, and symmetry as well as skills in graphing to complete the design, construction, and testing of their boats. Student designers also learn about energy conversion, boat hull design, drag, tools, and materials. The variety of options - materials, hull shapes, propulsion systems - assures that a selection of different boats will emerge from the design process.

Designing a Power Boat

Middle or high school students are challenged to design a self-propelled toy boat. They must choose boat materials, determine hull shape and a propulsion system, build the model, and conduct a variety of tests and measures to design an efficient craft. The following activity, one component of the design process, tests the boat's hull for efficiency and buoyancy.

The Test

The students will float their boats in a 2 m (6.5')-long trough filled with water to 1 cm (1/2 in) from the top. A plastic roof gutter, sealed to hold water, works well for this test. A pulley attached to one end of the gutter is threaded with a length of string weighted with a 150 g (5.25 oz) block. The string attaches to a boat's hull and the weight drags the boat through the water. A start and finish line mark the distance for timing and a stopwatch records the speed. A photogate sensor provides a more technical option for recording the speeds.*

Presenting the Problem

Design constraints for constructing the boat:

  • A variety of materials may be used, including wood, plastic, or metal. Styrofoam[TM] blocks can be used. Porous materials, like wood sheet stock, need a coating to reduce water absorption. Coatings can make the hull smoother, reducing friction, and increasing performance.

  • The boat can be no bigger that 8 cm (3.1") wide and 23 cm (9") long.

  • The boat can have no pointed, sharp, or loose parts that might injure children.

The Design Portfolio

Require the design teams to document their work in a portfolio with the following materials:

  • information gathered from resources;

  • drawings of all possible hull designs, providing views from the side, top, and bottom;

  • tables, charts, or graphs showing how the boat performed;

  • illustrations or descriptions of the science and mathematics principles used to design the boat;
  • all technology, science, and mathematics work completed during the activity;

  • notes made along the way.

* A photogate sensor is not essential to this activity. For further information about this tool, see page 8.

The complete 48-page Power Boat activity (ISBN: 0-02-636952-4) is available from Glencoe/McGraw Hill for $3.21 plus postage and handling. The complete binder (ISBN: 0-02-636947-8) with six activities is available for $61.98 plus postage and handling. For information call 1-800-334-7344.

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