Navsea Sl740-Aa-Man-010, U.s. Navy Towing Manual - Davis

Front 1

What is the primary materials used as tension members?

Back 1

Wire rope, synthetic fiber lines, and chain are primary materials used as tension members.

Front 2

What is often selected as a chafing pendant or bridle because of its abrasion resistance and survivability?

Back 2

Chain

Front 3

What is the primary tension element of the towline system?

Back 3

Tow hawser which is normally wire rope or a synthetic line

Front 4

For wire rope in conjunction with an auto. towing machine, a minimum safety factor of ____is appropriate for good ocean tows in good weather?

Back 4

Safety Factor of 3, a safety factor of 4 is recommended for routine tows to be conservative

Front 5

What is the breaking strenght for wet nylon?

Back 5

15% less than dry line

Front 6

What is a better suited material for towing applications?

Back 6

Polyester line

Front 7

What shall be rigged on all tows and is intended for emergency short-term use?

Back 7

Secondary tow line often made up with synthetic line

Front 8

Where can a secondary towline be rigged to tow?

Back 8

From either the bow or the stern

Front 9

For small tows what is used as a primary pendant?

Back 9

The ships anchor chain

Front 10

How long is the floating messenger on a small tow's emergency hawser?

Back 10

200 ft. with a small trailing bouy

Front 11

What should be used to connect chafing chain to the tow pad and what should not be used?

Back 11

A safety shackle should be used, pelican hooks should not be used.

Front 12

As a minimum for vessels above 600 L-ton displacement, the secondary towing pendant should be ______ wire rope with the necessary chafing gear?

Back 12

1 5/8 inch wire rope

Front 13

What are the towline attachment points on U.S. Navy tugs?

Back 13

The towing machine or the traction winch

Front 14

What are some attachments to the tow that may be at a hard point specifically intended for towing?

Back 14

deck padeye, chain stopper, or specialized tow bracket

Front 15

What is recommended for planned tows with newly installed attachment points?

Back 15

1. Non destructive testing (NDT)
2. Visual inspection of the attachment point and surrounding area
3. Dye-penetrant test of the padeye or bitt attachment point

Front 16

The breaking strenght of the line should not exceed ______ of the padeye's bitt, or cleats yield strenght?

Back 16

35%

Front 17

What is the "'dog" system on a towing machine?

Back 17

A pawl or ratchet type system that cannot be released against tension.

Front 18

What are the three types of padeyes found in towing?

Back 18

-Horizontal padeye
-Vertical free-standing padeye
-Towing bracket

Front 19

Chain stoppers are designed to bear ______ of the breaking strength of the chain.

Back 19

60%

Front 20

The width of the shackle-pin type padeye plate should occupy ____ - ____ % of the jaw width of the shackle, to prevent it from racking and creating loads?

Back 20

75% - 80%

Front 21

What 4 kinds of shackles can be used as towline connectors?

Back 21

*Type I anchor shackle
Grade A - Regular
Class 3 - Safety Bolt and Nut

*Type I anchor shackle
Grade B - High Strength
Class 3 - Safety Bolt and Nut

*Type II chain shackle
Grade A - Regular
Class 3 - Safety Bolt and Nut

*Type II chain shackle
Grade B - High Strength
Class 3 - Safety Bolt and Nut

Front 22

T or F screw pin shackles can be used for connections in towing rigs?

Back 22

False

Front 23

T or F cotter pins for shackles can be used for towing?

Back 23

False, replace cotter keys with locking bolts with jam nuts.

Front 24

In detachable links, what is the safest and most cost-effective method to secure the tapered pin into the link?

Back 24

A hairpin

Front 25

What are the 3 types of wire rope terminations?

Back 25

1. Swaged
2. Spliced
3. Socketed

Front 26

Properly made swaged eyes develop ______% of the strength of the wire?

Back 26

85%

Front 27

What are the advantages of swaged fittings made of special alloy steels?

Back 27

High efficiency and low cost process

Front 28

Why are hand spliced eyes so popular?

Back 28

Field repair capability

Front 29

How can a fiber core wire rope be swaged properly?

Back 29

It can be swaged by replacing the fiber core at the termination with a strand of wire

Front 30

A wire splice with properly placed wire clips will withstand ______% of the wires breaking strength?

Back 30

80%

Front 31

What wire termination will withstand 100% of the ropes breaking strength?

Back 31

Poured socket (spelter socket)

Front 32

What is used to make a poured socket termination?

Back 32

Poured zinc

Front 33

Spelter socket is prepared IAW NSTM, Chap _____ ?

Back 33

NSTM Chap 613

Front 34

What are the approved Navy standard thimbles used as end fittings for synthetic line?

Back 34

-Thimble with end link
-Closed thimble
-Synthetic rope thimble
-Nylite thimble

Front 35

As a rule of thumb the size of the chain to use for the bridles and the pendants should be at least equal to what?

Back 35

equal to the size of chain used to anchor the tow

Front 36

What is the optimal bridle apex angle?

Back 36

Between 30-60 degrees

Front 37

How do you rig a back up securing system for a towing bridle?

Back 37

Lacing wire rope through the chain links and securing it to a second securing point

Front 38

How do you verify that both of the bridle legs are the same lenght?

Back 38

By counting the links when the rigging is complete.

Front 39

What is usually the lead pendant and how long can it be?

Back 39

Up to 300 ft. of wire rope

Front 40

What is the minimum bridle retrieval pendant size and what safety factor is considered?

Back 40

5/8-inch wire rope
safety factor of 4:1

Front 41

What does the term freshing the nip mean?

Back 41

Periodically adjusting the scope of the tow wire to reduce the wear on any one point.

Front 42

What is usually selected as the safety link and is sized to have a breaking strength ____ to ____% below the main tow hawser?

Back 42

Wire rope with a breaking strength 10 to 15% below the the main tow hawser

Front 43

What are the function of the tow bows?

Back 43

To keep the towline clear of all deck fittings and furnish a protected area where personnel can pass safely.

Front 44

The vertical stern rollers and norman pins onboard the ARS 50 class ships will drop when a load of ________ lbs. or more is applied to mid barrel height?

Back 44

50,000 lbs

Front 45

niska

Back 45

back of the neck

Front 46

When using a hogging strap what is perferred over using a shackle?

Back 46

Saddle like fittings because they have a larger radii