Help and Support


Q: The crane I want to buy is rated at H2-B3. What does that mean?

A: H2 is a lift class. Basically, a crane rated at 'H2' can lift a full load twice as fast as a crane rated at only 'H1', and last just as long. Your work gets done a lot faster.

A: B3 is the stress rating. If a 'B2' crane and a 'B3' crane work side by side in average service, the 'B3' crane will last 3 times as long! in heavy service the 'B3' crane will still last 30% longer. Compare 13 years of service to only 10 years with a 'B2' rated crane.

Q: What is a marine crane?

A: A marinized or marine crane is built to withstand corrosion from sea air and saltwater. This often includes special paint and metals. Many also have more powerful gearboxes to withstand the extreme working conditions.

Q: What is meant by the crane rating or 'Lift Moment'?

A: This is the load capacity of the crane in either tonne-metres (Tm) or foot-pounds (ft.lbs.) for example, if you need a crane to lift 2000 lbs at a distance of 10 feet, then your crane must be rated at 2000lbs*10 feet, or 20,000 foot-pounds.

Q: What are the advantages of a Hexagonal or 'Hex' Boom?

A: Hexagonal boom cranes always stay in alignment, so they never shift from side to side, even as they wear.

Q: What about crane safety?

A: Please refer to the section on Crane Safety for a list of common safety devices found on cranes.

Q: How many degrees of rotational angle (or slewing angle) should my crane have?

A: Most cranes are limited to a given number of degrees, and some cranes are designed to rotate 'continuously' which means that you can rotate the crane nonstop in either direction. Be sure to provide a detailed explanation of your application when you are shopping for your new crane so that you get one that is right for you.

Q: What is the difference between a Mono Boom Crane and an Articulated Crane?

A: A mono boom crane has a single straight boom. This is the most common small crane design. An articulated crane has two or more booms and is a popular design in larger cranes. Articulated cranes can be quite long and yet fold up into a very compact unit for transport, and are also known as folding or knuckleboom cranes.


Q: How do I power my crane?

A: There are several ways to do this and each has distinct advantages:

Hydraulic power: A PTO pump can be attached to most standard transmissions and some automatics as well. There are several advantages to this including lower cost at the outset and in the long term, as well as a 100% Duty Cycle, and improved cold weather performance.

A clutch pump can be mounted onto most truck engines, and has all the benefits of a PTO pump with the added bonus of remote start/stop using an electric switch.

Electro-Hydraulic power: The basic crane in this application is often the same, but instead uses electric power from the vehicle it is mounted on. This type of power supply lets you mount a crane anywhere you can get 12 volt or 24 volt power, or in places where hydraulic power is not practical. If you want to mount the crane somewhere stationary instead of on a truck, this is a very effective solution.


Counterbalance Valve This very important device has many useful functions. The counterbalance valve used in this example has all of the following features:

  1. Holding — if a hydraulic hose ruptures or is torn off, the affected cylinder locks in place to prevent the load from dropping.
  2. Smoothing — helps operator to perform smooth starts and stops when operating the crane.
  3. Load Limiting — limits the pressure in the cylinder to ensure safe operation and protect the crane from damage by overload.
  4. Thermal Relief — if a large increase in temperature occurs where the crane is stored, the thermal relief opens to prevent rupture of the cylinder or lines.
  5. Prevents Creeping — all hydraulic valves bypass slightly, especially as they wear out. A counterbalance valve prevents the hydraulic cylinder from moving due to this small bypass of oil, often known as creeping.
  6. Emergency Lowering — in the event of a hose rupture or general failure of the hydraulic system, the counterbalance valve can be used to slowly lower the crane to bring the load down.

Anti-Two Block This switch prevents damage to the crane or sudden breakage of the cable that can be caused by winching the cable in too far.

Load Limiting Device This device activates during an overload situation and allows only those operations that will ease the overload condition, such as retracting the boom or lowering with the winch. It resets automatically once the overload is reduced.

Low Angle Switch This switch works in conjunction with the load limiting device to prevent the lift cylinder from bottoming.

Low Cable Switch This switch prevents the cable from spooling out too far where it could separate from the winch or begin to wind in reverse.


Q: What does a stabilizer do?

A: A stabilizer extends out from your vehicle or from under your crane to prevent the vehicle from tipping and to allow your crane to lift its capacity.

Q: How do I know which stabilizer to choose?

A: Read further to find out more about the types of stabilizers available, then contact your dealer for more information on models to suit your application.

Q: What do you need to consider when you buy stabilizers?

  1. Manual or Hydraulic raising/lowering. Choose hydraulic except on very small cranes.
  2. Manual or Hydraulic horizontal extension. This is a labour saving device and essential on larger stabilizers.
  3. Stabilizer Rating (dynamic moment). This term refers to the load that the stabilizer can carry. Your dealer will help you determine which size you need.


If you have a service related question about BIGMAX cranes that you'd like to see answered here, please send it to info@bigmaxcranes.com.