Help
Options
Didn't know it?
click below
click below
Knew it?
click below
click below
Don't Know
Remaining cards (0)
Know
retry
shuffle
restart
0:00
Embed Code - If you would like this activity on your web page, copy the script below and paste it into your web page.
Normal Size Small Size show me how
Normal Size Small Size show me how
UWSH - CH 9, CE
CH. 9 Sonar Rubber Domes
| Question | Answer |
|---|---|
| SRD material | No-Foul rubber |
| Safety note for no-foul rubber | avoid skin contact, mask and goggles |
| Note for securing cofferdam to SDRW | 4 clicks strap ratchet, then check clearances |
| Bow mounted test pressure | 30 psi |
| keel mounted test pressure | 20 psi |
| What is done before a dry inspection | Leak check required prior to personnel entering dome for inspection |
| Markings for wet inspection | (With High Contrast pen, yellow or white) Mark damage Waterline: skeg meets keel, above location of damage marriage Line: Centerline/stem, above location of damage |
| Structural repairs required | damage (pits, bubbles, blisters, flaps, cuts) greater than 2" or when there are exposed wire plies |
| Grooming repairs only required | damage (pits, bubbles, blisters, flaps, cuts) less than 2" |
| requirement for cofferdam | water temp 60 deg. F or less, or high turbidity |
| Radiography for which type of Sonar dome? | bow mounted only |
| Berthing/Prep specs | 10' below lowest point of SDRW/SRD at MLW Ship moored repair side to pier 100' pier space for equipment |
| Things needed for cofferdam | steam, freshwater, electrical No cofferdam-just fresh water |
| Two types of patches used | 1A 3 |
| type 1A patch dimensions | 52"x27" |
| type 3 patch dimensions | 27"x27" |
| How far do edge bolts go from edge? | approximately 1" |
| How to bolt patches | Bolt from center outwards and engage structural wires |
| Patches only bend... | In one direction |
| Epoxy material | BF Goodrich HP-2 Elastolock |
| Epoxy bond time | 5 days |
| Epoxy pot life | 50 minutes |
| Workability of HP-2 starts to degrade at... | 30 minutes |
| Epoxy mix ratio | 7:1 |
| Common damage to sonar dome, common causes of cavitation | razor sharp cuts and old repairs |
| Markings for testing | -Mark SRD surface so tape crosses patch perpendicular to damage -Mark undamaged part opposite repair for comparitive measurements |
| Bow mounted sonar domes are on... | CVs and DDGs |
| Keel mounted sonar domes are on... | FFGs |
| Noise spokes commonly caused by process called______ | Cavitation |
| What is a radiographic inspection used for? | Locating wire ply damage under rubber that could lead to dome rupture |
| Sonar Self-Noise Correlation Study identifies noise within how many inches? | 6" |
| NoFoul rubber coating thickness | 1/4" |
| How to skive around perimeter of damaged area | Use New scalpel and go around damaged area at 45 degree angle |
| Use a _____________ to clean whole surface area to be repaired, within _______ ft of the damage | Hand Held hydraulic rotary grinder, wire cup brush 1 ft |
| Clean repair areas with ___________ | Hand held hydraulic grinder with NEW wire brush |
| Structural repairs are required when ________ or more wire plies are exposed broken. | 1 |
| Each patch can only be applied ________. | Once |
| Divers direct topside to start mixing HP-2 within how many minutes of finishing surface prep? | 10 minutes |
| What tools should not be used for SRD repair? Why? | pneumatics Power and torque losses when used underwater |
| How is HP-2 transferred from topside to divers | In sealed ziplock bag filled with water |
| Apply HP-2 to repaired area, working into roughened dome surface _____ to ______ inches beyond boundary of patch. | 2-3 |
| As much as 4 sq ft of HP-2 may need to be applied requiring how many divers? | 2 |
| How thick should uniform layer of HP-2 be? | approximately 1/4" thick |
| How should prepared patch be lowered to divers? | In a sealed plastic bag with enough water in it to prevent surface contamination |
| Minimum dome thickness for patch Minimum lag bolt length | 1" 2" |
| Dome rubber is thickest at.... Gets thinner.... | Marriage Line The farther away from the marriage line |
| Minimum lag bolt engagement into wire plies | 1/2" |
| Test pressure for bow mounted | 30 psi |
| Test pressure for keel mounted | 20 psi |
| When testing patch for leaks, increase pressure in ______ psig increments and hold for _______ to visually inspect for leaks. | 5 psig 10 minutes |
| Times and speeds for OP test underway | 1 hour, 12 knots 1 hour, 15 knots 1 hour, 18-20 knots |
| Divers need to complete what prior to sonar dome repair? | NAVSEA OOC5 sonar dome repair course Shall have recent experience with sonar dome repairs |
| Approximate time requirements for nonstructural/grooming repairs | less than 1 hour per groomed area |
| Time for installation of #3 patch | 3 hrs |
| Time for installation of 1A patch | 6-8 hrs |
| Bow mounted cofferdam rigging | 1. D strap from skeg up to around top of ship 2. Skeg bridle rigged where skeg meets keel 3. A strap positioned from skeg bridle to forward around centerline 4. B straps horizontal by marriage line 5. 2 vertical c strap assemblies (for sides of C/D) |
| Bow mounted cofferdam Cofferdam install | Lower down, e strap placed along top of cofferdam to A strap 4 clicks on ratchet strap, then check clearances. Repeat until cofferdam seated completely |
| Requirements for repair when using cofferdam | -Fresh water -110 VAC, 60 HZ power source -steam |
| Fresh water heated in cofferdam by __________ | heat exchanger |
| Steam pressure is between _______ and _________ psig | 50-70 |
| Walkthrough of patch installation | Place elastolock on correct curve of patch |
| Keel Mounted Cofferdam: Fwd/aft rigging slings topside | Fwd-12 ft round sling Aft-3 ft round sling |
| rigging gear between slings and cofferdams (top to bottom order) | -3/4" shackles -30 ft wire rope pendants -3 ton chain hoists -3 ft lazty pendants at all corners -3/4" shackle to cofferdam |
| Which testing method is used to locate wire ply damage? | Radiographic inspection |
| Which testing can be done by ships force to locate the origin of noise within 6" | Sonar self-noise correlation study |
| Why turbidity in water affects SRD repair | created a "release agent" between adhesive and rubber. |
| SRD Grooming repair walkthrough | -skive around damage w/ scalpel at 45 degree angle -HHRG new wire cup brush, clean all fouling within 1 ft of damage (immediately before HP-2) -Topside mix HP-2 w/ in 10 min of finishing -Work HP-2 onto surface w/ hands |
| Grooming repairs: What to do before HP-2 smoothed with pipe roller | Trim excess HP-2 from around perimeter of damage |
| SRD Structural repair walkthrough: | -Test fit/make markings -divers surface prep area, spread on HP-2 -Topside clean/apply HP-2 to backside of patch, lower -Place patch, bolt center to outwards, install edge bolts -Roll/smooth fairing areas -Fill bolt holes with HP-2, trim/smooth |
| Why do we mark the patch area around the patch? Why do we mark the patch/dome orientation? | -defines dome surface to be prepared for patch adhesive -Prevent the patch from being turned/installed the wrong way |
| How to tell which side of the patch is the front/back | front-lettering back-no lettering |
| As much as _______ sq ft of elastolock may have to be applied for a particular patch. Requires how many divers? | -4 sq ft -At least 2 divers |
| How much adhesive does topside apply to backside of patch before lowering it to divers? | uniform layer 1/4" thick |
| Types of bolts used in SRD patch | lag bolts |
| Minimum lag bolt length for any location is what? | 2" |
| Lag bolts must be long enough to _______ | Engage wire plies |
| Why are patches bolted from the center outwards? | Forces Excess HP-2 to come out the sides of the patch which will be used for fairing edges of patch afterwards |
| After lag bolts applied to patch, do what to perimeter of patch? | Install 1.5" bolts around edge of perimeter at 3" spacings approximately 1" from edge of patch |
| Fairing band pipe rolled around edge of patch with excess HP-2 should be approximately ______ wide and smooth. | 3" |
| Lag bolt lengths available | 2, 2.5, 3, 4, 5" |
| When should fairing the edges of the patch be done? | During and after bolting the patch (A diver should be dedicated to the task while the other bolts) |
| What material are lag bolts made out of? | Stainless steel |
| Specs for electrical supply to cofferdam | 110VAC/60Hz |
| water current during SRD jobs should be what? | Less than 1 knot |
| How many E-straps for bow mounted cofferdam -Located where? | 3 1 on top 2 on bottom |
| * |
Created by:
DivingKnowledge