A ship’s deck is used to transport many different types of cargo. It is installed from containers to large structures such as cranes or heavy modules of an offshore production plant. During transport, the ship confronts forces from the environment (wind, wave, current). Being on the ship’s deck, the cargo also encounters these forces. Cargoes…

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A ship’s deck is used to transport many different types of cargo. It is installed from containers to large structures such as cranes or heavy modules of an offshore production plant. During transport, the ship confronts forces from the environment (wind, wave, current). Being on the ship’s deck, the cargo also encounters these forces. Cargoes must be stable while being subjected to these forces. They must be secured to the deck of the vessel using means such as lashing ropes, stoppers, beams, etc. This is called the “Sea-fastening” of cargo.

Sea fastening is the fastening of cargo while transportation at sea. When moving cargo by sea, it must be secured such that any movement which can damage cargo or ship must be avoided. Any major movement of cargo might result in instability problems. This might jeopardize vessels, cargo, and crew onboard.

Sea fastening of containers is done by stacking the containers in vertical guide rails. Another way is by stowing them in stacks or blocks, the containers being connected and fixed to parts of the vessel. The containers themselves are in a stack secured directly to the deck by bottom stackers or bottom twist locks.

How does ship travel on water affect cargo ship design?

There are various guidelines and standards which depend on the model and type of transport, yet most codes share the same tips when it comes to ensuring that the cargo is transported safely.

1. Heave

Heave is simply the vertical motion of the vessel moving up and down.

2. Surge

Surge is the linear longitudinal (front/back) motion. This causes the cargo to want to move to the front of the vessel and the rear of the vessel.

3. Sway

Sway, much like Heave, is a linear lateral (side-to-side) motion. This ignores any rotation of the vessel which we will cover later. This causes the cargo to want to move across the deck in the starboard direction.

4. Roll

The roll of a vessel is the rotation of an imaginary axis running horizontally along the ship’s length.

5. Pitch

The pitch of a vessel is the rotation of the axis running across the width. Pitch motion can be thought of as an up-or-down movement of the bow of the ship.

6. Yaw

Yaw rotation of the vessel on its vertical axis. This is the axis running vertically through the ship and through its center of gravity. Another way of thinking about yaw motion is the side-to-side movement of the bow of the ship.

What type of sea fastenings are available for cargo ships?

The heavier a cargo is, the stronger the acceleration forces will be. The position of the cargo on the vessel also affects the acceleration forces. It would be better to put the cargo on hold instead of on the deck or move it to a mid-ship position.

What happens if you plan for 2-meter-high waves, but then encounter 4-meter-high waves? Encountering a worse condition than what was expected is unlikely but is always a possibility. At the event, there is a bit of extra capacity for your lashing materials. Most surveyors look at the breaking point of the lashing material and divide that figure by 2.25 to get the Safe Working Load. This safety factor also accounts for any inconsistencies or impurities in the lashing material.

Lashing Materials such as chains, wire rope, or nylons are used to tighten the cargoes. The strongest material chains, which can last a long time. However, they come in fixed length, which provides fewer lashing options.

Wire rope is cheaper than chains and comes in a variety of sizes, making it more versatile than chains. You can cut the length you need from a spool of wire rope. However, wire rope is for one-time use and typically requires multiple personnel to make up the length and clamp down on the clips.

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History of Ladder There have been written records of how ancient Hebrew and Egyptian civilizations developed the world's earliest ladder and perfected it for various functions. An 8000-year-old cave painting was found drawn during the Epipaleolithic period, which is located at Cuevas de la Araña, eastern Spain. It depicts two people using a thin grass-like…

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History of Ladder

There have been written records of how ancient Hebrew and Egyptian civilizations developed the world’s earliest ladder and perfected it for various functions.

An 8000-year-old cave painting was found drawn during the Epipaleolithic period, which is located at Cuevas de la Araña, eastern Spain. It depicts two people using a thin grass-like ladder to collect honey from a bee’s nest.

Why is the boarding ladder important for the ship crew?

In the past, most of the ship crews used a flexible hanging ladder for access over the side of ships. It consists of vertical ropes or chains supporting horizontal, historically round, and wooden, rungs.

Currently, the boarding ladder is used in ports, at sea, or in anchorage to get crew onboard ships or vice-versa. It is hinged on a platform attached to the side of a ship and which can be positioned to provide access between ship and shore. According to the requirements for safely rigging vessel access equipment in SOLAS regulation, adequate lighting should be provided to illuminate the means of boarding ladders on both sides. At the same time, it shall be well-positioned and avoid the lower part of the ladder and gangway overhanging off steep ship sides.

How can ship crew maintain the boarding ladder for their own safety?

Ship crews should assign a team of people to be in charge of the boarding ladder and ensure that it is functioning. A normal regular check-up must be done.

They must ensure that the embarkation and disembarkation areas should be clear, and cargoes are not to be placed around the place.

A lifejacket and a safety harness must be put on a crew if he or she oversees stowing the boarding ladder.

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Development of hatch covers over the years The ideal hull on a ship would be a hollow, watertight chamber. At the same time, it can provide access. They were originally fitted with cargo hatch covers consisting of wooden hatch boards. Steel beams will be fitted in to support the hatch opening. In sailing vessels, the…

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Development of hatch covers over the years

The ideal hull on a ship would be a hollow, watertight chamber. At the same time, it can provide access. They were originally fitted with cargo hatch covers consisting of wooden hatch boards. Steel beams will be fitted in to support the hatch opening.

In sailing vessels, the cargo hatches used to be small to preserve the integrity of the hull. Decks are often awash during ocean passages and the smaller the opening, the smaller the risk of flooding the holds.

Bigger ships and smaller crews led to the invention of the mechanically folding steel hatch cover. This is commonly known as MacGregor hatches. It consists of interlocking steel panels with rubber packing fitted inside the edges of the steel panels. A steel compression bar will be fitted onto the hatch coaming. In this way, the ship is deemed to be cargo-worthy by achieving its weathertight conditions.

Why hatch cover leak and what can it lead to?

Hatches leak for a variety of reasons, but mainly because of poor maintenance or failure to close them properly. When hatch covers show signs of leaking, the rubber gaskets are the first to gain attention. Ship crews may be able to change the gaskets themselves. However, some owners limit hatch cover attention to replacing the gaskets when worn out. In doing so, they miss out on many of the finer points of hatch cover maintenance.

Most hatch covers have movable parts like hinges, hydraulic cylinders, wheels, etc are all exposed to wear and tear over time and have an influence on how well the hatch covers work. At the same time, corrosion and physical wear of fixed parts of hatch coamings, hatch panels, storage racks, etc., may lead to leaking hatch covers.

Leaking hatch cover could lead to more serious consequences than wet cargo. This includes flooding, accelerated corrosion, or even loss of the ship. It is crucial for safety at sea and protection of the environment to maintain hatch cover weather-tightness and strength. The lack of hatch cover maintenance for hatch covers has shown to be the primary cause of water ingress into the cargo holds. Thus, this is how it leads to cargo damage.

Shipowners are obligated to deliver the cargo in the same condition as it was loaded onboard upon a contract of carriage of goods by sea. Cargo, which has been wet by seawater, will result in financial loss. Recovery claims will be filed against the shipowner carrier by the Cargo consignees and their cargo insurers. These claims can be very substantial depending upon the nature of the cargo and the amount of water ingress.

What is the test taken to check for hatch cover Watertight Integrity?

1) Hose Tests

The ability of the most used hatch covers to prevent water ingress depends upon the existence of a watertight seal between sections of rubber packing and steel compression bars.

The hose test involves playing a jet of water along the cross joints and perimeter seals of the hatch cover at a certain minimum pressure and distance from the structure. It requires a minimum of two people to carry it out. One to operate the hose and one to observe from within the hold to see whether water is gaining access.

2) Ultrasonic Tests

The use of ultrasonic equipment is a modern, viable means of testing for watertight integrity of hatch covers, access hatches, doors, ventilators, etc. It is preferable to use Class-approved equipment operated by qualified personnel and to follow approved test procedures.

The test involves placing an electronic signal generator within the cargo hold (laden or not) and using the receiving sensor to first take a reading at the access or booby hatch with the main hatch cover closed.

What are the basic procedures to maintain hatch cover for offshore assets?

Only qualified personnel should operate the hatch covers. They should be well-trained and be fully aware of the manufacturer’s procedures for the safe operation of the hatch covers. A proper risk assessment needs to be carried out and this needs to be reviewed regularly and ship crews are briefed and trained.

Special care and attention should be paid to the opening and closing of the hatch covers when the ship has an excessive trim or list. This is due to the possibility of the covers “running away” when in motion.

It is not recommended to open the hatch covers whilst at sea to carry out maintenance and repairs but there will be times when it is necessary. In such cases, it must be carefully considered, considering crew safety and the anticipated weather and sea conditions. It may be necessary to take extra measures to secure the hatch covers in the open position to prevent them from moving when the ship is moving.

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History of Riggers In the 19th century, ships sailed from there all over the world. Rigging was part of the overall strength of the ship when a rigger was a person working with ropes to hoist the sail. In an era before mechanical haulage, cranes, ropes, pulleys, and muscle power were all that were available…

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History of Riggers

In the 19th century, ships sailed from there all over the world. Rigging was part of the overall strength of the ship when a rigger was a person working with ropes to hoist the sail.

In an era before mechanical haulage, cranes, ropes, pulleys, and muscle power were all that were available to move heavy objects. The rigger is a skilled tradesperson who specializes in the assistance of manual mechanical advantage devices. It comprises a pulley, block, and tackle or motorized such as a crane or derrick or chain hoists (chain fall) or capstan winch.

Riggers attach loads of equipment to cranes or structures using shackles, cables, chains, clamps, or straps, employing pulleys, winches, lifts, or chain hoists (aka chain motors). Quick load calculations are necessary for each load and engineering principles are always in play. Riggers use various suspension techniques to get their load around obstacles on a construction site, loading dock, or event site to the desired location and height.

What is the role of Deck Riggers developed for Marine Offshore operations?

Deck Riggers are responsible for the lifting and moving of heavy and bulky objects, whether aboard ships or around the shipyard. They must develop a working knowledge of selecting and using the various rigging hardware, such as ropes, slings, shackles, clamps, chain falls, and come-a-longs. The rigger apprentice is trained on the proper hand signals involved in heavy lifts. Riggers must also be able to calculate the weight factors and angles used in the proper lifting and transferring of those heavy loads. They are responsible for installing the safety nets, anchor chains, and mooring ropes on board the ships and for line handling of the cables and ropes when docking or undocking the ships.

Deck Riggers is critical to successfully lifting operations for offshore operations. They know which hitches need to be tied and how much weight they can support. They need to understand how the center of gravity will affect a load’s balance and stability as well as how to find the center of balance.

Equipment that is commonly used in rigging includes slings, chokers, shackles, and winches. Through their competent usage, riggers enable heavy equipment to move through confined spaces as well as to tilt, turn or dip loads to avoid any environmental hazards.

Safety is of the utmost importance. This is especially so when heavy objects are being lifted by heavy equipment.

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