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 Based on the results of this inspection (i.e., internal structural weaknesses, hull plate
cracks, severe pitting or rusting, broken tension bar, excessive corrosion, etc.), a
decision will be made whether to prepare the buoy for a detailed inspection or to
dispose of it.
5.2.2 DETAILED INSPECTION. Perform detailed inspection as follows:
Ultrasonic Testing. Conduct this test as follows:
5.2.2.1
Sandblast the buoy to near white metal in accordance with SSPC-SP-
q
10.
Inspect the buoy for damage, cracks, etc.
q
Conduct an ultrasonic thickness test at four points on the buoy top,
q
four points on the bottom, and eight points around the
circumference of the hull. Four of the foregoing eight points will
be below the waterline and four above the waterline.
Using a pitting gauge, measure the depths of any pits observed on
q
the hull of the buoy. (Refer to Paragraph 5.2.2.2 following.)
Pitting Inspection. A visual inspection of the buoy hull plates will be
5.2.2.2
made for pitting. The extent of pitting will determine the remaining life
of the plates. ASTM G46-76, "Examination and Evaluation of Pitting
Corrosion, " will be the standard reference used to evaluate the damage
a n d to formulate a quantitative expression that will indicate its
T o obtain a quantitative expression, ASTM G46-76
significance.
r e c o m m e n d s that the deepest pit be measured, and that metal
penetration be expressed in terms of the maximum pit depth or the
average of the 10 deepest pits. Metal penetration can also be expressed
This is a ratio of the deepest metal
in terms of a pitting factor.
penetration to the average metal penetration as shown in the following
relationship:
50
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