Mounts Flashcards
Why are resilient mounts used on a ship?
To reduce the amount of radiated noise transmitted to the ships hull
What safety precautions must be carried out on equipment before changing mounts?
LOTO procedure
What references can you use for information on changing mounts?
Mounts data manual - MAP 01-473
UMMs job card
What is the process when carrying out mount replacements?
Loosen the mount holding down nuts
Use jacking bolts closest to mount
Replace one mount at a time
What is the correct method of changing mounts?
Replace mounts as a set
Use correct replacement mounts
Machine to be fully supported using jacking bolts
Name 5 types of mounts used in the RN
J
M
L
PD
X
What measurements must be carried out on a mount after installation
The deflection of the mount or clearance of the base plate from seating
When using X mounts what must not be done?
Must not be used in conjunction with any other mounts
Must not be wrapped, taped or covered in anyway
What must mounts not show signs of when supporting machinery?
They must not show any signs of displacement, relative to ships structure
Must not appear spongy or contaminated
Must allow a degree of dampening to prevent excess motion
Once mounts have been replaced what must you allow the machine to do?
If time allows, especially on M mounts and high load X mounts, allow machine to settle for 24 hours and occasionally rock back and forth to allow permanent displacement
During a build or refit, how are mounts protected?
A waxed wrap followed by a water adhesive fabric around them
What is creep?
The tendency of a solid material to move or deform permanently under the influence of mechanical stress
How do you ensure the correct locking of the nuts for each mount
Nyloc nuts are to be fitted. The holding down bolts are to be of sufficient length to fully engage with the nylon element of the locknut, but should not provide through their nuts by more than one thread
What are the correct fitting arrangements for an X mount?
The head of the securing bolt should be fitted from the inner side of the mount
the threads protruding outwards and nylon brushing provided is to be used
What should be fitted to mounts if they are in a hostile environment
Heat and oil shields with a minimum 6 mm clearance
When inspecting mounts What points should be considered?
Paint, oil or fuel contamination
Signs of distortion, damage or misshaping
Creep
Over tightening
Incorrect fitting
When does an X mount need to be replaced?
When greater than 20% of damping compound has seeped
12 years after date of manufacture due to degradation of damping compound
What allowances should be made when taking measurements after installation?
Temperature changes
X mounts 40 mm clearance around the machine
In addition to the mounts what other component parts can be fitted?
Accelerator and deceleration units
What is the adjustment height for both the L and M type mount decelerator?
Clearances are set to 3mm
(Tolerances -0mm, +1mm)
What is the outcome if tools or projections are left around or under a machine base?
It impairs the efficiency of the mounts and prevents the full movement of the machine during shock/ vibration
What are the correct fitting arrangements for an X mount?
The head of the boat should be fitted from the inner area of the mount
The threads protruding upwards and all nylon brushing provided are used
When carrying out an inspection after installation what should you look for?
All jacking bolts have been raised clear
All tools and loose gear have been removed
When replacing mounts what must you consider?
Replace the mounts one at a time leaving packing pieces in their original position
Draw and label the X mount
Refer to docket
In the event of shock damage, what must be carried out and when?
VA of equipment and mounts as soon as operational circumstances permit
What is the application of a PD mount
It is a general purpose mount for heavy equipment
Not a fully captive design therefore fitted with accelerators and decelerators
How are mount positions identified?
Using lettering system A,B,C and D
Starting stbd fwd corner working clockwise
How is deterioration of rubber mounts indicated?
Soft to touch
Swollen
Sticky to touch
Aged
Heat hardened
Oxidised/ crumbled
What is the load range of L mounts?
5-130kg
What is the total range covered by M mounts?
340-450kg
What is the load range of X mounts?
9-550 kg
What is the load range of PD mounts?
750-2500kg
When should checks on a J mount be carried out?
Every 4 years or after the vessel has been in The vicinity of an under water explosion
Why is vibration isolation necessary?
Minimise radiated and self noise to improve habitability for the crew
