Draft Survey: Specimen of Calculation

As I have promised you, I write down this post to explain specimen of Calculation in Draft Survey. Please also refer to the previous post Draft Survey : Procedures and Calculation.

Ok, now we could directly go to the point. The vessel has alongside at the wharf in port to discharge the grain cargo. The Ship’s Particulars shown :

Name of Vessel : MV. OCEAN BALL, – Port of Registry (POR) : Panama, – Lenght Over All (LOA) : 182.00 M, – Lenght Between Perpendiculars (LBP) : 179.00 M, – Breath (B) : 32.20 M, – Depth (D) : 17.15 M, – Gross Tonnage (GT) : 28,342 MT, – Net Tonnage (NT) : 17,664 MT, – Summer Draft (SD) : 12.163 M, – Summer Deadweight (DWT) : 52,998 MT, – Light Ship (LS) : 7,780 MT, Constant (CS) : 320 MT, – Fore Distance to Perpendicular (Fd) : 1.70 M, – After Distance to Perpendicular (Ad) : 9.45 M.  See Picture :

The Surveyor came onboard and made Draft Survey to determine the quantity of cargo on arrival. During inspection, she’s draft marks and others data finds as the followings :

– Fore Draft Port (FP) : 10.79 M / Fore Draft Starboard (FS) : 10.81 M.

– Mid Draft Port (MP) : 10.90 M / Mid Draft Starboard (MS) : 11.03 M.

– Aft Draft Port (AP) : 11.16 M / Aft Draft Starboard (AF) : 11.19 M.

– Density of Sea Water Sample (Den) : 1.021.

– Ballast Water (BW) : 265.00 Cubic Meter at Density 1.025, – Fresh Water (FW) : 183.00 MT.

– Fuel Oil (FO) :  612.00 MT, – Diesel Oil (DO) : 161.00 MT, – Lub Oil (LO) : 29.00 MT.

Draft Survey: Procedures and Calculation

Finally, I have comfort time to complete this post after having busy with some surveys that I should fulfil. Any terms on this post should be refer to previous post Draft Survey: Terms of Conduct.

The Draft Survey procedures and calculation ascertained as the following series :

1. Reading the draftmark of the ship, which consist of six (6) points of draftmarks, i.e.; Fore, Midship, and After at both sides of the ship,
2. Sampling and testing the sea water or dock water density at the place where the vessel floats, 
3. Determining of deductible weights by measuring and sounding of ballast tanks, fuel oil, fresh water that existing onboard at the time of survey,
4. Using Hydrostatic Table provided onboard to begin calculation.

Draft Survey: Terms of Conduct

Before posting the step by step Draft Survey Calculation, it is necessary to attach the popular terms of conduct for Draft Survey for references. 

Aft Perpendicular (AP) : an imaginary vertical line, at right angles to the keel,  passing through the first frame and so located on or nearby the ship’s rudder post.

Ballast Tanks : tanks aboard the vessel specially designed to receive ballast water or, in the case of tanks vessels, cargo tanks used to contain ballast.