Mounts Flashcards
Why are mounts used in the RN?
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 ref can be used for changing mounts?
Mounts data manual MAP 01-473
UMMS Job card
What is the process for mount replacements?
Using jacking bolts closed to the mount
Prior to jacking up, loosen the mount nuts
Replace one mount at a time
What is the correct method for replacing mounts?
Replace mounts as a set
Use correct replacement mounts
Machine to be fully supported using jacking bolts
Name the 5 types of mounts?
J, M, L, PD and X
What measurements must be carried out after mount installation?
The deflection of the mount and the clearance of the base plate from seating
When using X mounts what must not be done?
Used in conjunction with other mounts
Must not be wrapped, tapped or covered in any way
What must the mounts not show signs of when supporting machinery?
Signs of displacement relative to ship structure
Spongy or contamination
Must allow a degree of dampening to prevent excess motion
After fitting mounts what must you do? (Especially on M and high load x mounts)
Allow the machine to settle for 24hrs and occasionally rock back and forth to allow permanent displacement
How are mounts protected during refit/build?
Protected by a wax wrap followed by a water adhesivefabric round them
What is creep?
Tendency of solid material to move or deform permanently under mechanical stress
How do you ensure correct locking of the nuts for the mounts?
New nyloc nuts are to be used
Bolts are to be of sufficient length to engage the element in the nut but not protrude more than one thread.
What are the correct fitting arrangements for a X type mount?
Head of the securing bolt from the inner side of the mount. Threads protruding and the nylon brushing provided are to be used.
What should be fitted to mounts in a hostile environment?
Heat and oil shield with a min 6mm clearance
When inspecting a mount what should be considered?
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 the dampening compound had seeped
What allowances should be accounted for when taking measurements?
Temp changes
X mounts 40mm clearance around the machine
In addition to mounts what else is to be fitted?
Accelerator and decelerator units
What is the adjustment height for both the L and M type mounts?
Clearance are set to 3mm + 1mm
What happens if tools or projections are left around machine bases?
It impairs the efficiency of the mounts and can prevent the full movement during shock/vibration
When carrying out inspection after installation what must you look for?
All jacking gear is raised clear
All loose tools and gear are removed
