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BOAT HANDLING

BOAT HANDLING. SAR Crew Manual Chapter 6. Boat Handling. Commands. Docking/ Undocking Commands. Let go forward/ aft Let go mooring ropes forward and aft All gone forward/aft Mooring ropes let go All clear forward/aft Mooring ropes are clear of the water/propellers

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BOAT HANDLING

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  1. BOAT HANDLING SAR Crew Manual Chapter 6

  2. Boat Handling

  3. Commands

  4. Docking/ Undocking Commands • Let go forward/ aft Let go mooring ropes forward and aft • All gone forward/aft Mooring ropes let go • All clear forward/aft Mooring ropes are clear of the water/propellers • Clearance 10 feet There is 10 foot between the boat at named place • No traffic port/stbd Lookout sees no traffic to endanger vessel

  5. Manoeuvring Commands • Steady Hold this course • Port/ Starboard Turn gently to port or Easy starboard • Hard a port/stbd Turn wheel all the way over to port or starboard • Port/ Starboard to Alter course to port to 000° or starboard to come to the specified course

  6. Engine Commands • Stop Throttles to neutral immediately • Take way off Use astern to take way off • Full astern Full astern to take way off immediately • Maintain Ahead speed just steerage sufficient to maintain heading • Trim up/ Trim Adjust trim tabs for Down optimum performance

  7. Personnel Commands • Secure Every person on board must get a secure grip on the boat and then answer “Secure”. Once everyone has acknowledged, vessel may rapidly increase or decrease speed, or make hard over turn. • Orders to move peoples around the boat to change trim of vessel.

  8. Vessel Reporting • Vessel 20° on port/ starboard bow, beam/ quarter • Vessel on steady bearing Probably involves risk of collision

  9. Touch Signals 1 • Stop Tap helmsman on top of head or helmet • Maintain course Push in middle of helmsman’s back • Slow down Pull on back of helmsman’s vest • Come slightly to Tap helmsman’s left port shoulder

  10. Touch Signals 2 • Turn to port Pull on the helmsman’s continuously left sleeve until desired heading is reached. • Come slightly to Tap helmsman’s right starboard shoulder. • Turn to starboard Pull on the helmsman’s continuously right sleeve until desired heading is reached.

  11. Forces on the Vessel

  12. Forces on the Vessel • Any vessel is subject to the forces of wind, sea, swell, tidal and ocean currents. • It is necessary for the coxswain to understand how these affect the vessel, and which forces will dominate.

  13. Wind Forces on the Vessel • Wind will always be a predominant force on a vessel, the more wind the more effect it will have. • The larger the surface area of a vessel is above the water, the greater effect wind will be. This is termed windage. • Any vessel will move downwind depending on the amount of windage, this movement being called “leeway”.

  14. Wind Forces on the Vessel • The angle a vessel rides to wind should be known. It is best found out by stopping the boat clear of land, and note what angle the boat settles down to in relation to the wind. • Take the time to test this. • This knowledge can then be used in all boat handling situations, such as docking/ undocking operations, recovering a person in the water or man overboard, etc.

  15. Sea Forces on the Vessel • Sea is the movement of the surface of the water by the passage of the wind over the surface. • These waves affect boat handling in various ways, depending upon their height and relative direction to the boat’s course, and the boat’s hull form.

  16. Current Forces on the Vessel • Current, whether from tidal flow or ocean movement, will affect the boat dependant upon the underwater shape of the hull. • This is called set (direction) and drift (distance). • The closer the current’s speed is to the speed of the vessel, the greater will be its relative effect.

  17. Current Forces on the Vessel • Learn the effects of current in your area of operation, in relation to the general ocean current rate, or the varying rate of the tidal current with regards to the times of high and low water, and the type of tide (spring or neap) • Spring tides have the greatest rise and fall (tidal range) therefore the fastest currents, whilst neaps tides have the lowest rise and fall, and therefore the slowest tides.

  18. Forces on the Vessel • Understanding how the combination of wind, seas, swells, ocean currents, tidal currents and outflows from rivers interact, and affect your vessel, will allow you to operate it safer.

  19. Forces on the Vessel • Tidal rip

  20. Forces on the Vessel • Gorge conditions

  21. Forces on the Vessel • Always check the conditions before going out, and continuously monitor the conditions whilst out, and be aware if they are deteriorating.

  22. Forces on the Vessel • Pay heed to the conditions when underway, manoeuvring off a distress or when leaving or approaching a dock, and use them to the best advantage, so you don’t end up unnecessarily fighting them.

  23. Vessel Characteristics

  24. Vessel Characteristics • A displacement hull will always be in the water, displacing its own weight of water to float. • A non displacement hull will be non immersed but riding across the surface. Examples are hovercraft, hydrofoils and RHIBs at speed. All of these will become displacement hulls when stopped. • RHIBs are called planing hulls.

  25. Vessel Characteristics • A displacement hull

  26. Vessel Characteristics • A non displacement hull

  27. Nautical Terminology

  28. Vessel Terminology Forward Towards the bow or forward of a named point on the vessel Aft Towards the stern Abaft Behind a named point on the vessel Aloft Above the deck or in the rigging Inboard Towards the centreline Outboard Outside the boat or towards the sides of the boat

  29. Vessel Terminology Port Side Left side, when facing bow Starboard side Right side when facing bow Centreline Line down the middle of the boat from bow to stern Beam Boat at its widest point or out at the sides of the boat 90° to its centreline Athwartships Across from side to side

  30. Vessel Movement

  31. Vessel Movement

  32. Trim

  33. Trim • Trim is the angle of the hull in reference to the water surface. • It may be adjusted by adjusting: 1. the angle of propulsion. 2. weights on board.

  34. Trim • The angle of propulsion is generally changed by adjusting the trim ram on the drive mount, on outboard engines, or trim tabs on inboards. • Trimming up increases the angle and drives the stern down while lifting the bow up. • Trimming down decreases the angle and drives the stern up.

  35. Trim • The ideal trim angle vs power ratio is when the boat is stable, and has the minimum of hull surface in the water.

  36. Trim - too high • If the boat is trimmed up too high, the boat may porpoise or chine hop. • Porpoising is when the bow hops up and down, even in calm water. • Chine Hopping is when the boat sways from one side to the other with increasing frequency.

  37. Trim - too low • The steering will be sluggish, and the bow wake will still be at the bow, and the boat will be pushing a lot of water.

  38. Optimum Trim • A good trim angle is characterised by responsive steering, and by the feeling the boat is floating on a cushion of air. • At this angle the boat is using less fuel, is more stable and is going faster.

  39. Propellers

  40. Propellers Having the correct and undamaged propeller, will greatly effect the speed, acceleration and fuel consumption of the engine.

  41. Propeller Parts Leading Edge Trailing Edge Inner Hub Blade Tip Outer Hub

  42. Propellers • Pitch - This is the forward travel measured in inches in one revolution.

  43. Propellers • Diameter - This is diameter of the propeller in inches.

  44. Propellers • Rake - This is the amount of degrees the propeller blades angle perpendicular to the propeller hub. • Most outboards are about 15°

  45. Propellers • Rotation - This determines the direction a propeller revolves around the axis of the propeller shaft. Rotation is determined by looking at the propeller from the rear of the boat. • A right hand propeller will turn clockwise therefore moving down to the right hand side. • A left hand propeller will rotate counter-clockwise or down to the left.

  46. Propellers

  47. Manoeuvring

  48. Manoeuvring • Use fenders, when available • When mooring with the wind off the dock approach at a steep angle. • When mooring with the wind onto the dock, come up parallel to dock, stop, and drift onto the dock. • Protect the stern and the propellers. With those you can generally get out of a problem situation.

  49. Manoeuvring • Whilst outboard engine and stern drives have a skeg below the propeller, and the casing is foil shaped at the propeller and above, for directional stability, the majority of the steering is from the screw discharge current thrust.

  50. Manoeuvring • Directed thrust is used in the following types of drives • Jet drives • Outboard drives • Inboard/ outboard drives

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