Question 1

Wt is dead weight,gt,nt

Accepted Answer

Tonnage is volume, not weight: gross for all enclosed space, net for earning space, deadweight for carrying weight. Gross tonnage from total enclosed volume V by K1 times V with K1 rising on log of volume — no exemptions. Net tonnage from cargo-earning volumes with passenger and service allowances under the 1969 Convention. Deadweight is the weight she may load to her marks — cargo plus bunkers, water and stores. All ships measured under 1969 rules by mid-1994; tonnage drives fees, manning and convention thresholds. Surveyor follow-up: bigger holds but same deadweight — gross, net or deadweight moves, and which certificate changes?

Question 2

Deadweight of my ship

Accepted Answer

Deadweight is what your ship carries: displacement at max draught minus the lightship — cargo, fuel, water, stores and crew. Lightship is the finished empty ship ready for service with machinery and outfit aboard. Deadweight adds everything consumable and saleable: cargo, bunkers, fresh water, ballast, provisions, crew and effects. Displacement mass equals lightship plus deadweight at the loaded waterline. Quote your own figures: lightship, summer displacement and deadweight with the load-line zone that limits them. Surveyor follow-up: deadweight up after deballasting with cargo unchanged — displacement, lightship or draught reading moved?

Question 3

Gt, nt dwt, light weight?

Accepted Answer

GT measures volume, NT measures earning volume, DWT measures carrying weight, lightweight measures the empty ship. Gross tonnage is total enclosed volume under the 1969 Tonnage Convention — unitless, for fees and rules. Net tonnage counts earning spaces from the same measurement for dues and registration. Deadweight is displacement minus lightweight: the tonnes you may load to the marks. Lightweight is the ship complete but empty — answer with your ship’s four figures, not definitions alone. Surveyor follow-up: GT unchanged after adding deck cargo gear — volume, weight or use changed, and which figure moves?

Question 4

Light weight dead weight net weight

Accepted Answer

Lightweight is the empty ship, deadweight is what she carries, net tonnage is earning volume — three different measures. Lightweight counts hull, machinery and outfit complete but empty of cargo, fuel, water and stores. Deadweight is loaded displacement minus lightweight: cargo, bunkers, water, stores and crew effects. Gross tonnage measures total enclosed volume; net tonnage measures earning spaces under the 1969 Convention. Answer with your ship’s four figures together — mixing weight and volume fails the oral in one sentence. Surveyor follow-up: deadweight up with lightweight unchanged and draught steady — displacement, stores or draught reading moved?

Question 5

A vessel of constant rectangular cross-section is 60 m long, 12 m beam and floats at a draught of

Accepted Answer

A rectangular box is the easiest displacement there is: volume is length × beam × draught, and displacement is that volume times density. With constant rectangular cross-section there is no block coefficient to complicate it — the immersed volume is simply L × B × d. Displacement in tonnes is that volume times the water density, about 1.025 t/m³ in salt water. The block coefficient for a true rectangular box is 1.0, which is the check that the arithmetic is right. Deadweight is then that displacement minus the lightweight, so the lightship figure is what the question turns on. Surveyor follow-up: displacement calculated without density gives 720 m³ not tonnes — which figure is weight and which is volume?

Question 6

Grt nrt dead weight

Accepted Answer

GRT and NRT are volume under the 1969 Convention; deadweight is the mass the ship may carry — two different kinds of number. Gross tonnage is the total enclosed volume in a unitless measure used for fees, rules and manning, not for cargo. Net tonnage is the earning volume from the same calculation, used for port dues and registration. Deadweight is the weight in tonnes a ship may load to the marks: cargo, bunkers, water, stores and crew. Answer by naming which is volume and which is weight — confusing them is the one error that costs the whole question. Surveyor follow-up: deadweight quoted in the same unit as GRT — which number, and what does each actually measure?

Question 7

Nt gt dwt

Accepted Answer

NT sits below GT because it is a subset, and DWT sits outside both because it is weight — the comparison that trips people is units. Net tonnage is always less than or equal to gross, since only the earning spaces are counted. Deadweight is not a tonnage at all: it is the mass in tonnes the ship can carry to the load line. So a ship of 30 000 GT and 21 000 NT might carry 45 000 tonnes deadweight — bigger than her tonnage numbers. Name the unit with the number: GT and NT are unitless tonnage, DWT is tonnes. Surveyor follow-up: candidate claims deadweight must be below net tonnage — what does the number actually measure?

Question 8

Unit of deadweight

Accepted Answer

Deadweight is in tonnes, and the fine unit is what matters: one tonne per 1000 kg of mass the ship may lift above her lightweight. Deadweight is a mass, expressed in tonnes, from displacement at the load marks minus the lightship weight. A tonne is 1000 kg, and in tonnage measurement the convention uses a 100 m³ or 1000 ft³ modulus for volume. So the surveyor expects tonnes for deadweight and a unitless tonnage figure for gross and net. It is the classic trap: stating deadweight as a tonnage figure rather than a mass. Surveyor follow-up: deadweight stated in m³ — is that a mass, a volume, and which way is the error?

Tonnage & Capacity — Most Asked Questions

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