# What is the procedure for Draft survey in brief?« Back to Questions List

 1. Loaded displacement = Light displacement + cargo + ballast + fuel + slops + fresh waster + constant 2. During initial draft survey we obtain the displacement as per the drafts and calculate the constant of the vessel 3. During final draft survey this constant is used to calculate the amount of cargo loaded using the formula given in I above. 4. Obtain visual drafts forward, midship and aft on both sides. Calculate the length between the marks (from stability booklet) 5. Obtain mean of ford, aft and mid draft 6. Calculate correction to all draft as follows Corr to forward draft = ( trim x distance of ford visual marks from forward perpendicular ) / length between marks Corr to aft draft = (trim x distance of aft visual from aft perpendicular ) / length between marks Similarly obtain corrn to mid marks Apply this correction to ford, mid and aft draft marks and obtain corrected drafts at perpediculars7. Now calculate the means of means or Quarter Mean draft by following - ( Corr forward draft + Corr aft draft + 6*Corr mid draft ) / 88. This draft is called Hydrostatic draft and enter the hydrostatic data tables using this draft to obtain the displacement, TPC, MCTC etc 9. First trim calculation is then calculated by following formula - (Trim x distance of Centre of floatation from midpoint bet perpendiculars x TPC) / LBPThis trim could be either positive or negative10. The second trim correction is then obtained by following formula - (50 x (trim)^2 x (MCTC1-MCTC2))/ LBP MCTC1 = MCTC at 50 cms greater than True mean draft MCTC2 = MCTC at 50 cms lesser than Tue mean draftThis correction is always positive.11.List correction is calculated in tonnes using - Correction = 6(d1-d2)(tpc1-tpc2) Where d1 and d2 are the drafts of immersed and emerged sides respectively And tpc1 and tpc2 are for those respective drafts12. The result will be Corrected displacement in Salt Water13. Density correction is then applied to the displacement if the vessel is floating in a water density different than salt waterThis displacement is then used in the formula mentioned in point No 1 to calculate the cargo loaded / discharged.13.Posted by marinetalesAsked on May 27, 2021 2:15 pm
 1. Loaded displacement = Light displacement + cargo + ballast + fuel + slops + fresh waster + constant 2. During initial draft survey we obtain the displacement as per the drafts and calculate the constant of the vessel 3. During final draft survey this constant is used to calculate the amount of cargo loaded using the formula given in I above. 4. Obtain visual drafts forward, midship and aft on both sides. Calculate the length between the marks (from stability booklet) 5. Obtain mean of ford, aft and mid draft 6. Calculate correction to all draft as follows Corr to forward draft = ( trim x distance of ford visual marks from forward perpendicular ) / length between marks Corr to aft draft = (trim x distance of aft visual from aft perpendicular ) / length between marks Similarly obtain corrn to mid marks Apply this correction to ford, mid and aft draft marks and obtain corrected drafts at perpediculars7. Now calculate the means of means or Quarter Mean draft by following – ( Corr forward draft + Corr aft draft + 6*Corr mid draft ) / 88. This draft is called Hydrostatic draft and enter the hydrostatic data tables using this draft to obtain the displacement, TPC, MCTC etc 9. First trim calculation is then calculated by following formula – (Trim x distance of Centre of floatation from midpoint bet perpendiculars x TPC) / LBPThis trim could be either positive or negative10. The second trim correction is then obtained by following formula – (50 x (trim)^2 x (MCTC1-MCTC2))/ LBP MCTC1 = MCTC at 50 cms greater than True mean draft MCTC2 = MCTC at 50 cms lesser than Tue mean draftThis correction is always positive.11.List correction is calculated in tonnes using – Correction = 6(d1-d2)(tpc1-tpc2) Where d1 and d2 are the drafts of immersed and emerged sides respectively And tpc1 and tpc2 are for those respective drafts12. The result will be Corrected displacement in Salt Water13. Density correction is then applied to the displacement if the vessel is floating in a water density different than salt waterThis displacement is then used in the formula mentioned in point No 1 to calculate the cargo loaded / discharged.Posted by marinetalesAnswered On May 27, 2021 3:13 pm