Cofferdams

Question 1

60. What chapter is shaft lamination?

Answer 1

13

Question 2

61. What are the 4 components do you apply on a shaft?

Answer 2

Primer, elastomeric, paint fairing compound, GRP

Question 3

62. What does GRP stand for?

Answer 3

Glass Reinforced plastic

Question 4

63. How long for it for GRP to set?

Answer 4

12 hours for first 2 wraps 12 hours for second 2 wraps

Question 5

64. How do you apply GRP?

Answer 5

1 and 3 are with the rotation with the shaft. 2 and 4 are the opposite way.

Question 6

65. What type of cofferdam do you use to do the shaft wrap?

Answer 6

Dog house dry chamber

Question 7

84. What chapter is cofferdams?

Answer 7

16

Question 8

85. Types of Cofferdams?

Answer 8

Patches, Plugs, Dry chambers, shaft seals

Question 9

86. J bolt measurements? Made of?

Answer 9

5/8” 3/8” Dropped forged steel

Question 10

87. DC plug protrusion?

Answer 10

3-4 in

Question 11

88. DC plugs made of?

Answer 11

Yellow Pine, Douglas Fur

Question 12

89. 2 types of Plugs?

Answer 12

Mechanical and wooden

Question 13

90. Where do you put the eye bolt on the DC plug? Why?

Answer 13

Off to the side so you can hit the hammer on the center

Question 14

91. Explain how mechanical plugs work?

Answer 14

Tighten wing nut to expand rubber into the hull opening of the ship

Question 15

92. What do you do with wooden dc plugs before installation?

Answer 15

Soak them

Question 16

93. Cofferdam materials for surface ship?

Answer 16

¼ 5000 Aluminum Steel, ¼ mild steel, 1” Marine grade Plywood

Question 17

94. Cofferdam materials for sub?

Answer 17

1/8 5000 Aluminum, 16 Gage stainless steel

Question 18

95. Foam material for cofferdams

Answer 18

Closed Cell, Type 2, Class B/C, Grade 1 or 2 above 35 Grade 2 below 35

Question 19

96. Ways to attach a cofferdam?

Answer 19

Clamps, wire rope, strong back, j bolt, belly band, Magnets

Question 20

97. Appendix’s for cofferdam

Answer 20

A: Cofferdam Materials
B: Dry chamber min calculations
C: Patch and Plug Inspection
D: Patch and Plug Installation
E: Divers min. training cofferdam
F: J bolt measurement requirements
G: Ship’s Requirements on cofferdam installation and removal

Question 21

98. Parts of a Jbolt?

Answer 21

Bushing, spring, wingnut, standoff, jbolt

Question 22

99. Ways to check cofferdam integrity?

Answer 22

Diver swim by, video camera, white water, vent hose floating, check for leaks, ships flood alarms

Question 23

102. MARMC approved cofferdams?*

Answer 23

Dc Plug, flat patch, box patch, dry chamber, shaft wrap

Question 24

103. Min Cofferdam foam can be compressed?

Answer 24

3/8

Question 25

104. When would you template? What is the measurement?

Answer 25

When the hull of the ship is curved and the cofferdam comes off greater than one inch.

Question 26

105. List ingredience for benski? How many rolls can you use per chapt. 16?

Answer 26

Rosin S25/W30 lb Cooking oil 5gal Cheesecloth 6x1 Bees wax 25lb Tallow 2/3lb Paraffin 2lb 1.5 rolls

Question 27

107. How do you attach a cofferdam without a grate?

Answer 27

Strong back, belly bands

Question 28

108. What is the definition of a cofferdam?

Answer 28

Any plug, patch, or dry chamber installed externally to the hull of a ship or sub below the waterline in order to secure/dewater area or system in order to conduct maintaince/repairs.

Question 29

109. Types of patches?

Answer 29

Flat, box, tombstone, thermos barrier

Question 30

110. Where do you put the vent hose and the educator?

Answer 30

Vent hose is above the eductor

Question 31

111. How do you dewater a space without a vent hose and educator?

Answer 31

Blow your pnumo into space and create a seal with the cofferdam. Ship will vent internally

Question 32

112. Explain the process of the stern tube seal?

Answer 32

Clam shell connects as a half moon to a full moon around the stern tube, hand tighten the clamp, Install two piece backing plate with all threads. Fully tighten backing plate to stern tube. Use all threads to push the clam shell flush with the stern tube opening. Then fully tighten clam shell. Check for leaks.

Question 33

114. What type stern tube coff. Do you use for the CG port side? Why?

Answer 33

Fat Rope because the angle the stern tube comes out of the hull of the ship

Question 34

47. Requirements for single valve?

Answer 34

Coms in space to divers 2 sources of dewatering Blank CO signature/permission Divers on standby

Question 35

132. 2 types of seals in a stern tube?

Answer 35

Clam shell, inflatable boot