Page 50 - statbility for masters and mates

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Ship Stability for Masters and Mates
Then
Let x The change in draft in millimetres x 1025 1010
FWA 25
x 150 15 25
x 90 mm
Ans. Draft will decrease by 90 mm, i.e. 9 cm
Example 4
AshipisloadinginaSummerZoneindockwaterofdensity1005kgpercu.m. FWA 62:5 mm, TPC 15 tonnes. The lower edge of the Summer load line is in the waterline to port and is 5 cm above the waterline to starboard. Find howmuchmorecargomaybeloadediftheshipistobeatthecorrectload draft in salt water.
Note. This ship is obviously listed to port and if brought upright the lower edge of the `S' load line on each side would be 25 mm above the waterline. Also, it is the upper edge of the line which indicates the `S' load draft and, since the line is 25 mm thick, the ship's draft must be increased by 50 mm to bring her to the `S' load line in dock water. In addition `S' may be submerged by x mm.
Fig. 5.5
x 1025 rDW FWA 25
x 62:5 20 25
x 50 mm
; Total increase in draft required 100 mm or 10 cm
and cargo to load Increase in draft TPC 10 15
Ans. Cargo to load 150 tonnes
Effect of density on displacement when the draft
is constant Shouldthedensityofthewaterinwhichaship¯oatsbechangedwithout theshipalteringherdraft,thenthemassofwaterdisplacedmusthave