DOOR FRAME
OR
STRAIGHTEDGE
HATCH
PULL
LG = ABT 30"
COAMING
STRING
TAUT
ALONG
DOOR
KNIFE EDGE
FRAME
OR
HATCH
COAMING
KNIFE EDGE
KNIFE-EDGE INSPECTION
KNIFE-EDGE INSPECTION
USING STRAIGHTEDGE METHOD
USING STRING METHOD
SAT
KNIFE
(STRINGS
EDGE
KNIFE
BARELY
EDGE
TOUCHING)
PULL STRINGS
TAUT ACROSS
1/4"
CORNERS
MAX
UNSAT
(STRINGS
TOUCHING
PULL
HARD OR
STRINGS
LARGE GAP
TAUT
BETWEEN
ACROSS
STRINGS)
SIDES
INSPECTION FOR TWISTING
INSPECTION FOR WARPAGE
Figure 3-11. Watertight doorframe inspection.
tolerances, initiate action to replace the closure. For
NOTE
further information, refer to NAVSEA Publication
For detailed instructions for maintenance
S9169-AW-DCB-010.
on watertight doors, refer to Shipboard
P M S C a r d s a n d NAV S E A P u b l i c a t i o n
Inspect the knife-edge for paint, dirt, rust, or nicks.
S9169-AW-DCB-010.
For steel knife-edges, remove paint and rust with #320
grit aluminum oxide abrasive cloth. Be sure to remove
Open the fitting (fig. 3-11). Inspect the knife-edge
the abrasive grit with a clean rag to prevent the grit
for straightness and/or warpage using a straightedge
from getting embedded in the gasket. For aluminum
and two lengths of string. The maximum acceptable
knife-edges, remove paint with a nylon scrubbing pad
variation for knife-edge straightness is plus or minus
and a rag only.
1/8 inch. The maximum acceptable warpage of the
doorframe is 1/4 inch. If frame/coaming warpage is
Inspect the entire knife-edge for proper height. A
block of aluminum cut to the correct specifications is
excessive or if knife-edge straightness is not within
3-9
