TOWING OPERATION QUESTIONS

THE TUG

• Why is navigating a tug more difficult than a larger vessel?
• Why are tugs usually built with low freeboard?
• Why must you stow all gear on a tug either below decks or on the deck above the main deck?
• Why do shiphandling tugs have narrow wheelhouses and hinged masts?
• Name two of the most important towing requirements for tugs?
• What is a kort nozzle and what is its purpose?
• What are flanking rudders and what is their purpose?
• Why do most tugs have stern control stations?
• What are the dangers in shifting from the wheelhouse controls to the stern station?
• Why are many tugs built with tumble home bulwarks?
• Why is a large bow fender important in ship handling work?
• What are the advantages of manila bow fenders over rubber fenders?
• What are towing pins (Norman Pins)?
• What is a gob rope?
• Why do tugs have so little reserve buoyancy?
• What is free surface effect?
• Why must you watch your decks in heavy weather?
• Why do tugs have portable pumps?
• What guidelines should you follow when requesting spare towing gear for your tug?
• When rigging battery powered navigation lights on a tow, how long should you expect them to remain bright?
• What line handling problems may tugs with controllable pitch propellers encounter?

THE CAPTAIN

• What knowledge must a capable tug captain have?
• Who is responsible for displaying the navigation lights and shapes on a tow?
• What log entries should a tug captain make when picking up a tow?
• What is the tug captain’s role in maintaining towing safety?
• Why is a good searchlight essential at night?
• Why should a tug consider shortening her tow in fog or periods of poor visibility?
• What procedure would you follow to find a vessel reported adrift?
• Why must a tug captain be cautious when crossing a ship’s wake?
• What should a commercial tug captain know before taking a naval vessel in tow?
• Why should all tows enroute to the United States be searched before leaving a foreign port?

SPECIALIZED WORK

• Why is ship docking more dangerous than barge work?
• When working alongside ships, barges or platforms what can you do to prevent flooding and contamination from overboard discharges?
• What are some of the disadvantages of handling large, deep-notched barges?
• What is the advantage of a deep-notched barge?
• Under what conditions is anchor handling required of tugs?
• In salvage work, what does “No cure, no pay” mean?

PUSHING AHEAD – RIVER AND CANAL TOWING

• What do the following terms mean:

o Facing up
o Facewires
o Sternlines and backing lines
o Jockeys
o Jackstaff barge
o Scabs
o Steamboat ratchets
o Cheater pipe
o Couplings
o Clevis
o Cavel or Kevel
o Timberhead
o Pike pole
o Toothpick
o Button
o Shackle
o Turnbuckle
o Thimble
o Fishplate

• What is the difference between a tugboat and a towboat?
• What are the main operating criteria for a river towboat?
• Why do towboats push on rivers rather than tow astern?
• What are push knees?
• How does a push-knee towboat make up to its tow?
• How does a towboat take the slack out of its towing pendants?
• What is one of the hazards of parting a facewire?
• What is one advantage of pushing a barge ahead with a tug in the notch?
• When pushing ahead, what effect will slack lines have?
• Is fiber line used in making up river tows?
• Why must turnbuckles, ratchets and winches be used on an integrated tow?
• When making up a multi-barge river tow, what factors must you consider?
• On river tows, what routine must you observe to maintain the integrity of the tow?
• Why are other vessels expected to reduce speed when passing tows pushing ahead or towing alongside?
• What does “hanging a barge off” mean?
• What is a deadman?

TOWING ALONGSIDE

• What does “towing on the hip” mean?
• What are the following lines used for when towing alongside?
o Bow Line
o Tow Strap or Spring Line
o Backing Line
o Stern Line
• What are the benefits of securing the tow strap and backing lines as close together as possible?
• How do you tow two barges on the hip at the same time?
• Why wouldn’t you work full ahead or full astern on a slack line?
• How does steering with a barge on the hip differ from steering light boat?
• How should lines that lead up to a ship or barge be secured?

TOWING ASTERN

• What must you consider when towing astern in shoal water?
• What is the danger of having your towing wire drag on the bottom?
• When is a tug “in irons”?
• What length of hawser permits adequate control over a barge in harbor areas?
• What should you consider when entering a harbor with a tow on the hawser?
• How should you handle the line while retrieving the hawser?
• How would you change from hawser towing to alongside towing?
• What are the principal differences between how a tug using a tow winch and a tug towing on the hawser shorten up when entering the harbor?
• What tendency may a barge on a short hawser exhibit through winding channels?
• What is a “lizard stopper”?
• How do currents and eddies affect the tow?
• Does a tug ride better with or without a tow in moderately heavy weather?
• What effect does wave action between a tug and its tow have in heavy weather?
• What is the advantage of using a long towing hawser on an ocean tow?
• What can you do to reduce strain on the hawser in heavy weather?

COASTAL TOWING

• What is coastal towing?
• What is the principal difference between a coastal and ocean tow?
• What types of hawsers are used in coastal towing?

OFFSHORE AND OCEAN TOWS

• Who should inspect the tow before it leaves on an ocean voyage?
• Who inspects vessels that are in class and registered with a registered classification society?
• What part does a surveyor play in approving a tug and its tow for an ocean voyage?
• Must a surveyor make recommendations for every offshore tow?
• What towing preparations must you make for an ocean tow?
• What does “securing” mean?
• List a number of causes of ocean tow failures?
• Why is an inland barge susceptible to damage during an ocean tow?
• What should you take into consideration when planning to depart from port?
• What’s a “tail boat”?
• Why should shallow draft, twin-screw tugs not be used for ocean towing?
• When are ocean tows manned?
• What duties must a riding crew perform aboard the tow?
• Why should a tug on an ocean tow have a small seaworthy boat?
• How should a towed vessel be trimmed?
• How are spill pipes leading to a chain locker prepared for an ocean tow?
• What steps must you take to secure sea valves and other through hull fittings on a tow?
• How and why must a breakwater be constructed on a barge being prepared for an ocean tow?
• What would you do to protect a ship’s superstructure during a tow?
• What type of ballast is commonly used?
• What may the sound of air escaping from a vent or manhole cover indicate?
• What is a bullnose or bullring on a ship?
• What does “rake packing” mean?
• When is it important to ballast a tow?
• Why is it poor practice to ballast the rake end of a barge?
• Why is seawater used as ballast?
• How should emergency towing gear be installed on a towed vessel?
• What are backup wires and how are they used on an ocean tow?
• How should rudders be secured on a vessel under tow?
• What are the advantages of removing the propeller of a ship being prepared for an ocean tow?
• How should you secure the shaft on a ship being prepared for an ocean tow?
• How would you secure deck cargo on a barge preparing for an ocean tow?
• What are tomming and shoring?

SINGLE, MULTIPLE AND BREASTED TOWING

• What are the chief advantages of a single tow?
• What is the most serious problem that a single tow faces?
• Why may it be better to tow two barges from two hawsers rather than connecting the barges in tandem?
• Identify these terms:
o Tandem towing
o Christmas tree method
o Modified Christmas tree method
o Honolulu method
o Pendant
o Flounders
o Fishplates
• How are two tugs of unequal horsepower or size hooked up for towing in tandem?
• What is the difference between tandem tugs and tandem towis?
• How would you tow a large vessel with two tugs?
• How do two tugs, preparing to tow in tandem, make up their tow?
• Where should the tug and each barge of a two barge tandem tow be positioned when leaving from or arriving at a dock?
• What are the most difficult phases of handling a tandem tow?
• If two tugs on a hawser are pulling together trying to free a ship that has gone aground, how should their hawser lengths compare?
• What is the best place to make up a tandem tow?
• How might you tow two barges in tandem if the deck fittings on the lead barge are not suitable for towing another barge astern?
• How do you make the necessary connections when preparing to stream a tandem tow of two barges astern of one tug?
• What does “breasted tugs” mean?
• When is a single tow with two tugs in breasted formation used?
• How does one tug keep out of the way of the other on a breasted tow?
• How can two or more breasted tugs control the yaw and surge of a heavy cumbersome tow?
• What are the advantages and drawbacks to a Christmas tree rig?
• How would a Christmas tree hookup affect the catenary of the towing hawser?
• What prevents the towing cable from surfacing under the intermediate barges while using a Christmas tree rig?

TOWING HAZARDS

• Why must you not abandon a tow that has gone adrift?
• Describe what happens when a tow yaws.
• Describe several types of yawing action that a tow may take.
• Why is yawing dangerous to a tug?
• Why is yawing dangerous to the vessel in tow?
• What problems does yawing present in calm waters?
• How can yaw be reduced or eliminated in a tow?
• What are the drawbacks to rigging a heavy chain droque astern of a tow to reduce its yaw?
• Why are some barges built with two skegs that are toed outward?
• Who makes the decision to release a tow if it starts sinking?
• Where are the most dangerous places to be on a tug when a tow starts to sink?
• What are the most important considerations when confronted with a sinking tow?
• When would you avoid releasing a sinking tow?
• What is the principal danger of towing on a short hawser?
• What factors can cause a tow to override its tug?
• If a tug suffers a mechanical breakdown in deep water, what problems may its towing cable cause?
• What obstructions can restrict the safe navigation and maneuverability of a tug and tow?

BOLLARD PULL

• How can a tug determine its towing load?
• When does the towline pull reach its maximum?
• What is static bollard pull?
• What is the rule of thumb relating bollard pull to horsepower?
• What factors beside static bollard pull must be considered before assigning a tug to a towing job?
• What difficulties are directly related to using excessive towing power?
• What does jumping the line mean?
• What should you do if the mid-section of your towing hawser continually jumps clear of the water?
• What are the effects of wave action on a towing hawser?
• What effect does the resistance of the tow, the thrust of the propellers and the weight of the towing wire have on a tug?
• What effect does lengthening the towline have?

THE TOWING WINCH

• How does a towing winch operate?
• Is chafing gear used on a tug equipped with an automatic towing engine?
• What type of towing winch is used to make tandem tows offshore?
• What is a dog on a towing winch and how does it operate?
• What is the principal disadvantage of using a dog on a towing winch?
• How should you evaluate the catenary of a tow wire while towing?

THE TOW HOOK-UP

• What is a tow hook-up?
• Which offshore towing hook-up is considered to be most trouble-free?
• How strong should the gear used in the make-up joining the tug and its tow be?
• What size should the towing bridle be in comparison to the main towing hawser?
• What is the best angle to use at the apex of a towing bridle?
• What wear problems can chain bridles cause?
• How do you connect a towing bridle on an ocean tow?
• Why may it be unwise to secure towing bridles to existing mooring bitts and fittings on deck?
• What practical problem may arise from making up a bridle that is too long?
• Why is it difficult to make up a bridle that is too short?
• What problems arise from towing a ship with the bitter ends of her anchor chains as bridles?
• What type of bridle is best for use in ice conditions?
• Why are retrieving lines connected to chain bridles?
• Do tugs with a wire hawser make up directly to the bridle on their tow?
• Why do you need elasticity in towing?
• Why is manila and other natural fiber rope seldom used as a surge line?
• What would you use as an intermediate spring hawser on a long distance ocean tow?
• Why are synthetic fiber hawsers preferred over heavy chain for surge pendants between a tug and its tow?
• Why should only one intermediate spring hawser be used?
• What is chafing gear and where is it used?
• What is the purpose of a towing board?
• What type of chafing gear can protect a fiber towing hawser as it passes over a towing span, buffalo rail or bulwarks?
• If you are towing from the H bitts and the hawser is stationary, what types of chafing gear can you use?
• What is a gob rope?
• What is the purpose of a towing strap?
• Are screw pin shackles satisfactory for towing?
• What can old hawsers be used for?

FIBER TOWING HAWSERS

• What factors limit the use of fiber towing hawsers?
• What must you consider when selecting a suitable towing hawser?
• What is small stuff?
• Why do splices in synthetic fiber lines require more tucks than natural fiber lines of the same size?
• What is one of the most important yet most hazardous jobs on a tug?
• What precautions should you take when heaving in a hawser on a capstan?
• What type of fiber makes the best all-around towing hawser?
• What is a notable characteristic of nylon stretched to the point of breaking?
• What are the principal advantages of polypropylene hawsers?
• What happens if the towing hawser contacts the shallow areas of the bottom?
• What spare towing gear must a tug carry?

WIRE TOWING HAWSERS

• What are the recommended guidelines for wire rope towing hawser selection, use, maintenance and emergency reconnection?
• How are wire hawsers connected to a towing bridle?
• What is the approximate diameter and length of a wire towing hawser?
• What type of wire rope is generally used for a wire towing hawser?
• How do you estimate the breaking strength of wire rope?
• What is the function of a fiber core in a tow wire?
• What is one advantage of a fiber-core wire towing hawser?
• While inspecting a wire rope towing hawser, what should you be alert to?
• How do you inspect the heart of a wire towing hawser?
• At what points is a main towing hawser subject to wear?
• What effect does a sudden jerk have on a wire towing hawser?
• How much damage can a sharp nick inflict on a wire towing hawser?
• What damage can insufficient lubrication inflict on a towing wire?
• How can you reduce the wear on one point of a towing cable?
• When should you renew a wire towing hawser?
• What type of maintenance must you perform on a towing wire?
• What does “end for end” mean?
• How are wire towing hawsers stowed?
• When installing a new tow wire, how do you secure it to the winch drum?
• Why must you spool the wire onto the winch drum smoothly and tightly?

MISCELLANEOUS

• What is downstreaming and why is it dangerous?
• List 20 different potentials for injury while working on tugs and barges.

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