Banksman

In Irish and British civil engineering, a banksman is the person who directs the operation of a crane or larger vehicle from the point near where loads are attached and detached. The term 'dogman' may be used in Australia and New Zealand, while 'spotter' is the more common term in United States.
Offshore & Oil and Gas.
The general term for a professional banksman offshore is a ‘rigger’ or deck crew. A team of riggers will manage lifting operations. There are specific methods, pieces of equipment, and safety protocol for many different types of loads. Offshore, on rigs or vessels, most equipment and materials will arrive on location, transferred by boat utilising a crane, therefore banksmen play an important role in the marine and offshore industries. 
Contemporary.
Crane or large vehicle drivers do not always have clear visibility of the loading area, especially when tower cranes are employed. The banksman is in charge of the crane movements from the point of loading and unloading. They may use a system of hand signals or a radio link.
A banksman may also be responsible for directing the movement and loading/unloading of lorries, or directing the movement of other plant. A banksman may also control the movements of an excavator, by carefully monitoring the bucket for any obstructions or underground services.
In many countries, banksmen are required to meet a regulated standard, such as laid down by the UK's Health and Safety Executive; in the UK over a quarter of vehicle deaths at work are due to reversing vehicles.