UWSH CH 16

Question 1

Are plugs authorized that are wrapped in fabric or rubber?

Answer 1

No, only bare plugs are authorized

Question 2

DC plugs must be what?

Answer 2

Standard Stock or Equal

In Good condition; no Chips, gouges, cracks

Question 3

Are mechanical plugs with aluminum components authorized?

Answer 3

No, due to galvanic corrosion they are not

Question 4

The plug must have a seating pressure rating of at least how many times the static pressure head it will be sealing?

Answer 4

One and One Half

Question 5

What must be stamped on the end plate of the permanent waterproof tag attached to the plug?

Answer 5

The size range of each plug

Question 6

Can a mechanical plug sealing surface be trapered?

Answer 6

No, must remain untappered

Question 7

The top plate or washer must have an outside diameter larger than the opening being secured.

What kind if plug is this?

Answer 7

Mechanical Expandable Plug

Question 8

When installing a plug when can diver leave the dive station?

Answer 8

1 - Not until Double Valve protection is stablished
2 - Repairs are complete
3 - The ship CO or his designated representative grants their permission

Question 9

On flat bottom hulls what can divers use to assist them in relocating a plug?

Answer 9

A C-Clamp installed on the bilge keel, this also will not interfere or obstruct traffic along side

Question 10

The expansion of the plug, rather than a differential pressure secures the plug in place and from the seal.

What type of plug?

Answer 10

Mechanical Expansion Rubber Plug

Question 11

The diver must always ensure that this kind of plug is completely seated an sealed before checking for leaks

Answer 11

DC Plugs sealed with Binsuke

Question 12

How do divers inspect patches with no means of internal venting?
(Sea Chest & Piping Systems)

Answer 12

Visually inspect by divers for reduced gasket compression indicating loss of seal on the internal not to exceed every 7 days

Question 13

When using J-Bolths to attach a patch to a sea chest grating or spreader bars, the patch should be ____ over the opening?

Answer 13

Centered

Question 14

What determines the extent of a rigging plan?

Answer 14

The type and size of the patch to be installed

Question 15

What must he rigging plan identify/include?

Answer 15

1 - lifting requirements
2 - securing and attachment requirements
3 - Manufacturer and weight testing requirements (lifting straps, wire)

Question 16

What is required for the installation of a cofferdam?

Answer 16

Rigging Plan

Question 17

How often must internal bents be inspected for signs of leakage by ships sounding and security detail?

For sea chest and piping with internal means of venting, location of the affected items shall be reported to the ships chief engineer per Appendix G

Answer 17

An interval not to exceed every seven days

Question 18

After installation of a patch what must be confirmed at he internal repair area prior to complete removal of pipping connection fasteners?

Answer 18

Zero Leak Rate Seal

Question 19

What is necessary to check after sealing a patch?

Answer 19

A final check of all support rigging and tightening of J-Bolts to verify integrity of patch

Question 20

After dewatering is complete, eductors shall be secured. Eductors ___ ___ be left running to maintain a differential pressures seal

Answer 20

Shall Not

Question 21

How are patches de-watered?

Answer 21

All patches shall be dewatered by draining the sea chest at an internal drain valve or piping connection or by use of an aductor installed directly on the patch

Question 22

What is the primary method of securing a patch to the hull?

Answer 22

J-Bolt or hogging lines secured to permanent structures, sea chest grates, splitter bars or the main deck

Question 23

When should a stand-off be used?

Answer 23

When the hull configuration limits the force applied to the hogging line

Question 24

What is essential to achieve a positive seal when installing a patch?

Answer 24

Removal of all fouling and corrosion

Question 25

What is the first step to installing a patch?

Answer 25

Locating and confirming against the docking plan that the valve or system to be removed corresponds to the system being blanked

Question 26

In locating a patch below the bilge keel the diver can follow what?

Answer 26

Vertical butt welds to the corresponding strake

Question 27

What can be used to extend contour lines out from the opening for reference in position the patch?

Answer 27

A paint stick or marker

Question 28

DC Plugs longer than __ inches may need to be trimmed to that maximum of 3 to 4 inches protrude from the opening after installation

Answer 28

8 Inches

Question 29

If an internal blank has been installed the integrity ..

Answer 29

of the plug must be re-established prior to removal of the blank
*Repair personnel must not assume a positive seal

Question 30

After the diver removes the plug he is supposed to remain at the work site, ready to reinstall the plug untill when?

Answer 30

Until he receives verification that no leak exist within the ship

Question 31

Prior to tightening a mechanical plug what must be verified?

Are cheater bars authorized to tighten mechanical plugs?

Answer 31

Verify that the backing plate is firmly seated against the hull

No cheater bars are not authorized