Transport on a vessel

Here's what you need to know when transporting a crane on a vessel, including: what to consider in the transport environment and when to use tie-downs.

Dynamic loads can impact a crane during transportation. Mobile cranes should be secured during transportation of the vessel. This is to prevent damage or cyclical loading of the crane.

Methods of securing may include:

• tie-downs between the crane chassis and the vessel
• swing locks
• placing the crane boom on the vessel deck or a boom cradle.

Damage could occur if the crane is not properly secured to the vessel during transport. Follow the relevant industry standards, guidance, inspection requirements and operator's manual.

A secured boom during transport

Note: Take care when supporting booms. Damage to boom lacings and chords may occur.

In a maritime environment, be aware of increased corrosion and dynamic loading.

Transport environment

Transporting a crane installed on a vessel has special considerations. Pay special attention to the environment the crane is being transported in.

Sailing areas covered in this guide include:

• protected inland waterways
• ports
• sea ports.

Transport in protected water conditions does not usually affect the crane with dynamic loadings.

The transport environment should be checked in advance. Irregular significant waves and wave heights might occur during transport. For example, caused by vessel traffic.

The stability of the whole crane and vessel combination should also be checked and approved.

Here's what to check in the transport environment of a crane on a vessel:

• wind speed
• significant wave heights specific for the selected transport route
• water depth
• wind induced water level changes
• high water cable and bridge overhead clearance
• tidal variations
• currents (speed and direction)
• turning circle of long components in narrow areas
• dimensional limitations on the transport route. For example, through bridges and locks.

After travelling on the vessel for extended periods of time, the crane structure should be checked for fatigue cracks.

Lashing and support of crane and crane parts

Laying down or supporting the boom can:

• make transport more stable
• reduce sensitivity against swell.

The machine should be put in a rest position, with the outriggers extended. The boom and counterweight should be supported on the deck of the vessel or the crane deck (as applicable).

It is recommended to use friction material (like anti-slip rubber or plywood) under:

• outriggers
• tracks
• the boom
• counterweight support points.

Also lashing the crane, boom and counterweight to the vessel deck might be needed if if the transport is across these environments:

• lakes
• tidal rivers, or
• where waves are to be expected (for example, due to vessel traffic).

Take care that no parts of the crane jut out beyond the profile of the vessel.

An example of tie-downs used during transport

Note: Lashing down cranes may cause damage due to loading the crane in a way not intended by the manufacturer. Consult the crane manufacturer or a qualified person for an appropriate tie-down plan.

Shifting or sliding of the crane

Anti-skid methods

During operations, the crane should be secured to prevent shifting or sliding. The use of anti-skid material or blocking are common methods to achieve this.

The chosen method of securing the crane from moving sideways needs to withstand the lateral forces that happen during lifting operations and transport. Calculations of the lateral forces are to be based on the expected maximum deck angle times a safety factor of 1.5.

When a crane is parked or during transport, the crane may be secured by using tie-downs.

Crawler crane secured with blocking

Timber pads or matting needs to be secured on vessel deck

When to avoid using tie-downs

Avoid the use of anti-skid material directly under outrigger supports. This is because it prevents the outrigger support from “setting” itself under crane loadings. Tie-downs should only be used according to the instructions of the crane manufacturer or tie down parts manufacturer. Avoid using tie-downs during operation without manufacturer's approval. This is because of extra forces being added to the crane chassis or the vessel itself.

Extra vertical loading could result in over constraining the crane and prevent the chassis from flexing as intended by the manufacturer. Never use tie-downs as a method to gain greater capacity.

So always be careful when using tie downs as the method of securement. Tie-downs may cause loading in the crane that was not intended by the manufacturer. Consult the crane manufacturer or a qualified person for an appropriate tie-down arrangement.

Assembling/disassembling of cranes on board a vessel

If a crane can't be transported onto the vessel in a rigged configuration, it might have to be assembled/disassembled on the vessel.