Ship Accommodation, Midship Section & Container Stowage

1. Know Your Ship's Particulars

A surveyor can ask ship-specific questions, so you must know your own vessel's details:

• What is your ship's accommodation length?
• How is a container secured in the hold?
• Draw a ship and explain the cargo hold length.
• How many containers are carried on deck and in the cargo holds?
• The answer to all such questions is simply to keep your ship's details ready — dimensions, capacities and securing arrangements.

Ship Particulars You Should Know:

• Length overall (LOA) and length between perpendiculars (LBP).
• Breadth, depth and summer draught.
• Gross tonnage (GT), net tonnage (NT) and deadweight (DWT).
• Number of cargo holds, hold lengths and hatch dimensions.
• Container capacity (TEU) in holds and on deck, and the number of reefer plugs.
• Number of crew, accommodation location and layout.

Why this matters. Surveyors use your own ship to test whether you truly know it. Details such as accommodation length, cargo-hold length, number of holds and container capacity are found in your ship's Capacity Plan, General Arrangement and Cargo Securing Manual — study them before the oral.

2. The Midship Section

Drawing and explaining your ship's midship section is a common surveyor request, especially for a container ship. The midship section shows the ship at her widest point and includes:

Why the midship section governs strength. Longitudinal hull-girder strength depends on the section modulus of the midship section — which in turn depends on the scantlings and layout of the structural members in the midship region. The midship region extends one-fourth of the ship's length forward and aft of midships; over this region member scantlings are kept the same, because the maximum longitudinal bending moment acts within this zone. Different ship types therefore carry different midship sections — statutory structural plans approved by the classification society.

• Strength deck / main deck at the top, with the hatch opening and hatch coaming.
• Side shell plating and the sheer strake at the deck edge.
• Double bottom with the centre girder, floors, bottom longitudinals and tank top.
• Hopper tanks (topside of the inner bottom) and topside tanks where fitted, forming the double side.
• Longitudinal and transverse framing with the web frames and deck longitudinals.
• Divided by transverse bulkheads into cargo holds, with the hatch above.

Read it from your own ship. Always base your answer on your ship's midship section drawing (in the General Arrangement/Construction plan) — naming the real structural members of your vessel is far more convincing than a generic sketch.

3. Container Terms: TEU, FEU & Dimensions

• TEU — Twenty-foot Equivalent Unit.
• FEU — Forty-foot Equivalent Unit.
• 20 foot = 6.1 m = 1 TEU.
• 40 foot = 12.192 m = 1 FEU.

Standard Container Sizes:

TEU is the unit of capacity. Ship container capacity is quoted in TEU. A 40-ft (FEU) container occupies two TEU, so a ship rated at, say, 8000 TEU can carry a mix of 20-ft and 40-ft boxes totalling 8000 TEU.

4. Weights & Securing Containers in the Hold

Weights:

• Tare weight: the weight of an empty container — the weight of the thing the object will be placed into.
• Net weight: the weight of the cargo placed into the container.
• Gross weight = Net weight + Tare weight.

Example: if a machine weighs 100 kg (net weight) and the container weighs 50 kg (tare weight), then gross weight = 100 + 50 = 150 kg.

Securing Containers in the Hold:

• Cell guides: vertical guides in a purpose-built container hold that locate and restrain each stack.
• Stacking cones / interbox twist locks: lock each container to the one below so the stack acts as a unit.
• Twist locks / base locks: secure the bottom container to the tank top (sockets) or deck.
• Lashings: lashing rods, bridge fittings and turnbuckles on deck stows, tensioned per the Cargo Securing Manual.
• Lashing plan: the approved Cargo Securing Manual gives the lashing pattern, maximum stack weights and forces for each stowage position.
• Weight distribution is planned so that the ship's stability (GM), trim and hull stresses remain within limits (checked on the loadicator).

Surveyor asks: "How is a container secured in the hold?" and "What is tare/gross weight?" Answer with cell guides, stacking cones/twist locks, base locks and lashings, and gross = net + tare (with the 100/50/150 kg example).