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SEAMANSHIP CH. 5 BOAT HANDLING PowerPoint Presentation
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  1. SEAMANSHIP CH. 5BOAT HANDLING REFERENCES: Chapman’s Chapter 6 and AUX study guide

  2. RESPONDING TO PHYSICS • Discovering the relationship between the laws of physics and boat behavior can be perplexing. • No two boats respond the same even under identical circumstances. • Successful boat handling requires practice.

  3. “HELMSMANSHIP” • The ability to steer well. • Cannot be mastered from a book or in a classroom. • Involves your “reaction - response” to the entire boat and it’s total environment including the weather. • You must attain the basics of “performance” from “hands on” experience in order to fully understand and master the “helm”.

  4. GOOD HELMSMANSHIP • Know Your Boat • Take it easy on another’s boat until you “get the feel” and know their boat. • Out of sight of land use compass and keep lubbers line on the course to be steered. • Near shore use landmarks

  5. BASIC TERMINOLOGYINBOARD OUTBOARD I/O THRUST PROPELLER • INBOARD: Engine mounted within the hull • OUTBOARD: Engine mounted on the transom and detachable. • I/O: Combination of inside and outside. • THRUST: Force moving the boat through the water, gained by a propeller. • PROPELLER: A “screw” which, when rotating. draws in water from ahead and pushes it out astern

  6. TERMINOLOGY Cont’dSINGLE/TWIN SCREW AUXILIARY INBOARD OUTBOARD • SINGLE SCREW: Boat with one propeller • TWIN SCREW: Boat with two propellers. • AUXILIARY: Sailboat fitted with an engine • INBOARD: Fixed direction of thrust, only changed by rudder action. • OUTBOARD OR I/O: Direction of thrust is changed by rotating the engine. Change of direction of thrust is the rudder.

  7. TERMINOLOGY Cont’dSTEERING THRUST RUDDER PORT STARBOARD • STEERING: Accomplished by CHANGING direction of thrust. • CHANGING THRUST DIRECTION: • By rudder action • By changing engine direction of outboard or I/O lower unit. • REMEMBER: PORT and STARBOARD sides are fixed, no matter which heading you have.

  8. TERMINOLOGY Cont’dHEADWAY• STERNWAY• TURNING•RIGHT/LEFT RUDDER • MAKING HEADWAY: Going forward in the water • MAKING STERNWAY: When backing down. • TURNING TO PORT: Bow is moving to the left. • TURNING TO STARBOARD: The bow moves to the right. • RIGHT OR LEFT RUDDER: Direction the bow turns to.

  9. TERMINOLOGY Cont’dRIGHT/LEFT HAND PROPELLERS SINGLE/TWIN ENGINES • RIGHT HAND PROPELLER: Screws through the water in a clockwise rotation, looking at the transom from the stern. LEFT HAND( the opposite). • Most single engine boats have RIGHT HAND props on them. • TWIN ENGINED: Usually have counter-rotating props to offset torque with RIGHTHAND prop on starboard, left hand prop on port side. Without counter-rotating props vessel would be almost impossible to steer.

  10. SCREW CURRENT • RUDDER(S) are placed in the center of the DISCHARGE flow and the current of water rushing by produces a pressure on the rudder blade which controls the direction of the boat moving in the water. • RUDDER(S) are ONLY EFFECTIVE, when the boat moves through the water.


  12. PROPELLERSTORQUE, EQUAL / UNEQUAL BLADE THRUST When moving foreword, RIGHTHAND props produce GREATER thrust to starboard at the stern AND LEFTHAND props produce Greater thrust to Port at the stern. ALL PROPELLERS RELY ON SMOOTH FLOW OF WATER for max efficiency.

  13. EFFECT OF TORQUE BY SINGLE SCREW • TORQUE will move the stern to the right. • ALWAYS visualize the DIRECTION OF MOVEMENT OF THE TOP of the prop for DIRECTION OF MOVEMENT OF STERN.

  14. HANDLING CHARACTERISTICSPLANING Vs. DISPLACEMENT HULLS • HEAVY BUILT: Displacement, load carrying hulls. Stable. Slower. • LIGHTER BUILT: Planing; Sport hulls. Shallower draft. Much faster. Less stable. • Both handle completely differently, especially in heavy weather • PLANING hulls revert to displacement hulls at low speeds.

  15. HANDLING Cont’dWIND•CURRENT Vs. HULL TYPES • HANDLING: ALL HULLS affected by WIND and CURRENT. • HIGH BOWS: Tend to fall off the wind NO MATTER what is done to prevent it, especially at low speeds. • CURRENT: Biggest reaction factor in all hull types. • DISPLACEMENT HULL: Current greatest affecting factor

  16. HANDLING Cont’dEXPOSED HULL AREA Vs. WIND • DRAFT• CURRENT • The more structure above the water, the more effect from wind. • The deeper the draft, the more effect from current. • Effect of current is greater than effect of wind on displacement hulls. • Effect of wind greater than current on planing hulls.



  19. MANEUVERING WITH DIRECT THRUSTOutboard and I/O 1. The boat is maneuvered by directing the propeller thrust. There is no rudder. 2. Directed propeller thrust makes slow speed maneuvering easier. 3. Normal or high speed turns are sharper. 4. May not respond well when there is no thrust. 5. While reversing, propwalk of reversing propeller tends to throw the stern to port, but to a lesser extent than inboard craft.

  20. MOORING LINES • BOW TO STERN • BOW LINE: Stops the bow from moving aft • BOW BREAST: Stops the bow from moving outward from the dock. • AFTER BOW SPRING: Stops the boat from moving foreword • FOREWARD QUARTER SPRING: Stops the boat from moving back • STERN BREAST: Stops the stern from moving out from the dock • STERN LINE: Stops the stern from moving foreword


  22. No Wind Or Current

  23. Close Quarters

  24. Use sharp angle of approach Secure after spring line Apply power and use steering control to bring stern to dock Go slow Wind Or CurrentOff Dock current wind or inboard

  25. Casting Off Wind On Dock Release stern line Place fenders Shift into forward Release bow line after stern is clear current wind or 3 2 1 3/10/2014 Ted Potter DCAPT/SHR

  26. Casting Off Wind Off Dock Release all lines Push boat away from dock Shift into forward and depart current wind or 3 2 1 3/10/2014 Ted Potter DCAPT/SHR

  27. REVIEW QUESTIONS NO. 1 • The part of the current that flows into the propeller is called the ___ _____ _____. • a. back lash current • b. back tide current • c. suction screw current • d. post screw current

  28. REVIEW QUESTIONS NO. 2 2. When a right-handed propeller is turning clockwise, the boat will go _________. a. forward b. backward c. to the right d. to the left

  29. REVIEW QUESTIONS NO. 3 3. The stern of a single screw boat with a left hand propeller tends to go _______when the propeller is reversing. a. to starboard b. to port c. ahead d. up

  30. REVIEW QUESTIONS NO. 4 4. When the rudder is put over, the stern is _____ the direction the rudder moves. a. kicked toward b. kicked away from c. kicked in d. not affected by

  31. REVIEW QUESTIONS NO. 5 5. When backing a single screw inboard with a right-handed propeller and rudder amidship, the stern will___________ a. go to starboard b. track straight back c. drift to starboard d. move to port

  32. REVIEW QUESTIONS NO. 6 6. The mooring line that keeps the boat from going ahead is the _____ a. Bow line b. Forward spring c. Breast d. after bow spring

  33. REVIEW QUESTIONS NO. 7 7. By going ahead on one engine while reversing the other enables a twin screw vessel to_______ a. turn in a much wider area b. turn within it’s own length c. turn within 1/3 of it’s own length d. back easier

  34. REVIEW QUESTIONS NO. 8 8. Getting away from a dock, when the boat is being set into it by the wind, generally requires using_____________. a. an after bow spring line b. a breast line c. a boat hook d. a stern line

  35. REVIEW QUESTIONS NO. 9 9. Breast lines are set ________ the boats hull. a. parallel to b. next to c. perpendicular to d. at 45 deg. angles to

  36. REVIEW QUESTIONS NO. 10 10. The discharge current of the propeller is always located on _______ a. the “down current” side of the propeller b. the “up current “ side of the propeller c. behind the propeller d. ahead of the propeller