Table of contents
- Section 1: History
- Section 2: Developments
- Section 3: Types of carriages
- Section 4: Types of harvesting
- Section 1: Terrain Requirements
- Section 1: Equipment yarder compatibility
- Section 2: Rigging & tieback configurations
- Section 3: Grapple body sensitivity to impact
- Section 4: Payload considerations
- Section 5: Lateral yarding opportunities
- Section 1: Removing people from exposed job environments
- Section 2: Roles which positively impacted by motorised grapple carriages
- Section 1: Improved efficiencies
- Section 1: Weight
- Section 2: Fire risk & suppressant
- Section 3: Durability
- Section 4: Reputable company
- Section 5: Spare parts & critical parts
Watch it on video: View our webinar series here
Part 1: Introduction to grapple carriages
To understand the complete grapple carriage picture, it’s necessary to take a step back and look at where we’ve come from in terms of logging methodologies, types of Grapple Carriages for logging on the market and how it influences your logging operation. In this Grapple Carriage Guide, we’ve broken it down into key sections to ensure an accurate representation of Grapple Carriages is given.
You’re probably aware Grapple Carriages aren’t new. They’ve been around for a few years in some form, and after a slow start they’ve proven to be a popular extraction method for harvesting due to their productivity output, reduction of people on the hill and ability to provide more control to yarder operator. Grapple Carriages are inherently safe and crews around the world have seen the benefits of removing the human element from their operations, which in turn reduces mistakes and has seen a dramatic drop in injuries.
Since the introduction of Grapple Carriages, there has been consistent development and continuous improvement by manufacturers wanting to refine their products, including both motorised and mechanical Grapple Carriages. Before taking a closer look at these innovations, here’s a recap on the different types of Grapple Carriages available in today’s logging.
|Type of carriage||Mechanised||Motorised|
Innovations introduced to improve motorised grapple carriages include:
- Incorporating high quality camera systems into the Grapple Carriages to live-stream video straight to the hauler operator’s cab
- Weight efficiencies to ensure that it’s fit for purpose for a range of tower and rigging configurations
- Addition of powerful LED lighting to increase safety and productivity in when vision is reduced
- GPS and positioning technology to enable ‘return to last pick-up point’, cycle time data and semi-automatic functions to reduce manual tasks
- In the future the ability to take advantage of the positioning technology to use a platform to host other technology and data for improving the wider logging operation productivity.
Types of harvesting
Harvesting is generally categorised into two main forms; ground-based harvesting and cable-based harvesting:
The ground-based harvesting technique is one which doesn’t rely on a hauler or tower set-up and all of the operation is carried out on the ground by either wheeled or tracked equipment or manual workers. Ground-based logging is typically cheaper as a harvesting method due to lower capital costs, quicker setup and faster processing/recovery of wood. While ground-based logging is the preferred method of logging, it is restricted to suitable terrain and topography, requiring flat or lower gradient to suit the machines’ ability.
Cable-based harvesting involves setting up a tower or yarder to recover wood from steep slopes or across tricky terrain using a rope-based extraction process. There are a wide variety of rope configurations and tower types across the industry. The type of yarder used is generally determined at the planning stage of the harvesting process and the type of yarder used influences the type of rigging configurations. There are many ways and methods to harvest a block and each contractor determines the most efficient to suit the crew and resources available, often in conjunction or consultation with the forestry management company. Cable-based harvesting enables wood to be recovered from steep terrain, as well as areas that are hard to access with wheeled or tracked equipment. Cable-based harvesting can be substantially more costly than ground-based logging, but for some forest plantations it is the only way the trees can be harvested.
When harvesting a block, it’s paramount to give due consideration to the methodology of harvesting to inform how the block can be accessed, where the landings are built, the length and run of the drags/settings and where other infrastructure needs to be constructed.
Harvest considerations which are specific to Grapple Carriages include:
- Lift & deflection: Which angles and slopes are most accessible to provide the desired deflection for a motorised Grapple Carriage to operated
- Length of setting: Motorised Grapple Carriages may be limited by the length of the line, dependent on the yarder.
Feasibility of logging with Grapple Carriage
When extracting stems and trees with a motorised Grapple Carriage it needs to be feasible to make it commercially viable for harvest and logging contractors. Below are some key factors to be aware of when considering a motorised Grapple Carriage (further information is also provided later in this overview):
Transitioning to another previous method of stem extraction requires physical changes such as having the right equipment and personnel training (we dive deeper into this later on)
Having additional equipment and capital, such as a motorised grapple carriage needs to be economically viable and in addition to this, it must have added benefits otherwise it won’t be seen as the most practicable solution. Economic benefits come in many forms for motorised grapple carriage which we explain further down but can be summarised as:
- Less downtime and injuries
- More reliability
- More payload
- Faster cycle times
Logging with a motorised Grapple Carriage is viewed as more socially acceptable as it reduces risk of harm by removing breaker-outs from dangerous working situations. Some people would argue that taking people off the hill is taking away jobs. The main point to understand is that this is provides an opportunity for crews and manual labour workers to upskill and add more value to the operation in other areas. You shouldn’t have to risk your life to have a job!
Part 2: Harvest Planning and Layout Considerations
When using a Grapple Carriage as part of your extraction process, there are considerations early in the planning process that need to be factored in, as it will influence your operation at harvest time.
Some factors include:
- Topography – avoiding boundaries, water courses or native planted areas
- Terrain – steepness and type of gradient
- Block size – Set-up and implementation stages for the whole block
- Wood size – the size of the stems can dictate the type of grapple used
- Specific requirements from harvest managers or planners
- Health and safety requirements
- Timeframe of harvest – volume of wood to meet demand or timelines.
Terrain requirements for using grapple carriages
Terrain plays a factor when using motorised Grapple Carriages, especially in relation to the type of setting. Below are some considerations:
Steepness: Grapple Carriages are ideal for pulling wood in a steep terrain environment.
Concave/convex: Not all slopes are equal. If the gradient decreases or increases over the terrain then the ‘curve’ in the slope it is known as concave or convex.
When comparing the difference in concave and convex slopes for Grapple Carriages, concave provide the best opportunities for lift and deflection. It may still be possible to use a Grapple Carriage on a convex slope, often with the assistance of an intermediate spar that provides the required lift in the rope to keep carriage and wood off the ground.
Length of pull
Grapple Carriages are often said to have a sweet-spot to operate in when it comes to length of pull, although this is limited to the type of yarder and yarder configuration used. They are suited to longer pulls, not just because of the faster recovery time, but also because they help to reduce stress on the tower/yarder and the rope itself. The lengthier the pull, the higher the stress loads.
Creating lift and deflection
Deflection is highly desired when pulling trees over gullies, across valleys and up/down sloping terrain. When lift is added to the operation, it not only improves the pull but also the payload of the motorised Grapple Carriage due to its ability to handle higher payloads.
Part 3: Grapple Carriage and Operation Compatibility
Equipment Yarder compatibility
Motorised Grapple Carriages work on almost all type of yarders, however they do have specific requirements. Many contractors who currently have a yarder set-up that is not compatible with a motorised Grapple Carriage may be able to make adjustments to ensure they are able to work together.
Types of Yarders
The types of yarders which are used with motorised Grapple Carriages.
- Tower yarders (also known as haulers)
- Swing yarders
- Shovel yarders (or excavator-based yarders or yarder loaders, ie yoaders)
Crew Requirements - training
Another operational requirement for a motorised Grapple Carriage is the crew having the skillset, training and knowledge to operate. When purchasing a new motorised Grapple Carriage, most distributors or manufacturers will commission, induct and train the operator to ensure he is competent and knowledgeable in operating after a few days of training. This helps to overcome the potential barrier to logging contractors purchasing new equipment, especially if unfamiliar with the product. In recent times, product support has improved substantially and should not be a concern when purchasing a reputable brand.
Rigging & Tie-back configurations
Depending on the yarder, setting and harvest plan a variety of rigging configurations are used with motorised Grapple Carriages around the world. Some of main configurations are described the below:
The Highlead cable configuration is the simplest and ‘crudest’ of the rigging systems. The mainline is used to pull the load in and the haul back line to pull the rope back if there is insufficient deflection and gravity for the motorised Grapple Carriage to be used.
The Running Skyline configuration goes one step further than the Highlead in that it is one looped cable that acts as both the line to return to the landing and also extract logs.
The Skyline configuration uses two ropes; one to support lift for the motorised Grapple Carriage (Skyline) and another to haul the carriage out.
The Live Skyline uses the strongest rope to provide lift and then a further mainline to haul the carriage back to the landing. Often this can be complimented with a motorised Grapple Carriage technique called ‘shot gunning’, which uses gravity to take the grapple carriage down to the harvested stems.
A Standing Skyline uses the slack-pulling carriage system which avoids the need to lower the Skyline and thus keeping lift and the carriage of the ground.
Tie-back (tail hold) considerations
When using a motorised Grapple Carriage, the carriage weight and payload needs to be considered in conjunction with the tieback method used. For example, if the piece sizes are small and the payloads are more than a few stems it could be a better option to use an alternative tieback method, such as a separate machine. When trees have a larger diameter, coupled with good soil structure, a stump-based tieback or buried deadman may be required.
Grapple carriage body sensitivity to impact
Grapple Carriages, especially motorised ones, can be sensitive to frequent impacts, however this should not be of concern if used in the settings and methods that are appropriate and designed to be used in. This is contrary to the misconception of motorised Grapple Carriages being easily damaged, which came about during in the early adoption period, when Grapple Carriage technology was new.
Further developments of Grapple Carriages has seen the durability and designs used by manufacturers improve significantly through increased research and development. Grapple Carriage manufacturers are acutely aware of how downtime when machines are not working of logging impacts crew operations and can be extremely costly, especially for those working in remote areas.
Current products on the market such as the Falcon Claw have been through considerable development and testing and remain dependable and durable options for motorised grapple carriages.
When comparing motorised grapple carriages with other alternative extraction methods for your operation there are aspects in relation to the payload that should be considered. Some examples are listed below.
Weight of the motorised grapple carriage will impact how much payload you’re able to pull and will influence your lift and deflection. This in turn may influence how you decide to harvest the lines you haul from.
The payload of the grapple carriage comes in the form of the grapple and the carriage component first, then if lift is a barrier, it would reduce the payload. However, if used correctly the payload of the carriage and the grapple design is the limiting factor. Many leading manufacturers offer grapples for specific extraction right down to the species, length and size of the stems.
When comparing payload to other carriages, motorised grapple carriages have a more consistent payload per cycle and although may be slightly less than conventional choker-setters and manual systems, the cycle times are substantially quicker for both shorter and longer lie pulls.
Lateral yarding opportunities
Most cable-based logging is often thought of as lineal however due to the rotating grapple on most motorised grapple carriage it provides an opportunity to think of alternative methods of extraction from a lateral sense with other rigging configurations. Example of this include a ‘live dutchman’ logging technique which allows lateral rope movement off the skyline. Other methods include have a piece of the equipment as the tail block which gets moved long dependent on where the stems are positioned and where deflection is needed.
Part 4: Safety with Grapple Carriages
This is where the bulk of the benefits of motorised grapple carriages come from. Especially when considering the people aspect of the logging operation.
When logging, it is important to remain profitable and productive whilst working in a safe working environment. Safety doesn’t and shouldn’t come at the expense of productivity but rather the two factors complement each other.
Getting people out of exposed job environments
Getting people out of manual and high-risk environments will not only benefit the workers and crews but also the business. Having someone exposed to choker-setting risks is not only a liability to the business and potential in downtime but more importantly a loss of someone who could upskill into another role within the operation.
Roles that positively impacted by motorised grapple carriages
Choker setting – removes someone exposed on the hill
Landing/ skid crew – removes the need to have a person on the landing unhooking stems
Yarder Operator – Has complete control of his extraction process and isn’t dependant on communication of colleagues.
Spotter – no need for a spotter which may be needed with grapples without camera systems
Part 5: Performance Measure
Specific costs with Grapple carriages
Grapple Carriages, especially motorised Grapple Carriages come with specific and extra costs, which aren’t seen with alternative recovery methods. So contractors are keen to find a major gain or benefit that can be derived from the additional costs. Let’s look at the additional costs and then highlight the benefits of motorised grapple carriages.
- Capital cost – finance and funds tied up in equipment may be more for a motorised Grapple Carriage
- Servicing – it is important to choose a reputable manufacturer to reduce motor servicing costs
- Fuel – a cost to be aware of if you’re transitioning to an ICE motorised Grapple Carriage, although latest models are very fuel efficient
- Rotating grapple associated costs from ongoing maintenance and wear/tear
- If using a larger or heavier carriage then additional rope wear may be seen, however there are rope wear savings in keeping the cable off the ground.
Over-all Benefits of Motorised Grapple Carriages
Below is an overview of benefits seen when using a motorised Grapple Carriage:
Future-proofing your operation – increased mechanisation within the industry
Mechanisation is a growing trend and contractors understand that it is vital to keep up-to-date with safety and efficiency advancements to remain competitive and to also open up opportunities to compete for more contracts.
Ability to completely mechanise harvest operation
Adding a motorised Grapple Carriage to your operation enables the recovery of wood from steep sites to complement existing mechanised felling resources, so that contractors can comply with a forestry manager’s mandate to be fully mechanised.
Quicker cycles and turnaround times
Improving cycle times remains the easiest way to boost the extraction part of a harvesting operation. When cycle times are faster, even with smaller payloads, the level of productivity can increase substantially.
Productivity per hour
Removes people from the hill - no need for a spotter
In addition to the safety benefits of taking people off the hill there are additional savings. These include admin, payroll, and employee-related costs, which are indirect employee expenses that can may be saved when transitioning to a motorised Grapple Carriage.
Placement of trees for quick extraction
When coupled with a mechanised felling machine the extraction productivity can be significantly increased through the placement and bunching of trees to optimise the use of the Grapple Carriage. The benefits include less time in trying to latch the grapple onto the stems laying on the ground, as well as less time spent on line shifts, maximising payloads and providing quicker cycle times for the grapple carriage. There are also environmental benefits through keeping the stems out of waterways or near native blocks and also reducing damage to the ground through better control over stem recovery.
The cost per tonne to run a Grapple Carriage is dependent on usage and volumes of wood coming in per day, which should be weighed against the substantial benefits already mentioned. Typically, daily running costs for a Falcon Grapple Carriage are in the vicinity of $300-$350/day, derived from:
Fixed costs, ie:
- Interest repayments or the capital invested as an opportunity cost
- Servicing, which is tied to machine hours
- Potential increase in wages as staff are more skilled
- Rope wear if you haven’t been using Grapple Carriages
These costs need to be balanced against the extensive benefits, including:
- Cost savings in rope wear and yarder component wear
- Cost savings in potential injuries, sick days and loss of time incidents
- Cost savings in all other indirect employment and HR related costs (payroll, holidays, travel etc)
- Cost savings in scalability – using the Grapple Carriage across multiple blocks or shifts
Lifetime costs vs pay-off timeframe
How does that stack up for you operation? Only you will know the answer but if you divide your daily loads or tonnes-per-day rate by the costs mentioned above, you’ll be able to paint a picture of the benefits specific for your operation. There is also a important aspect to consider is the benefit of a motorised grapple carriage after paying it off. For example, the Falcon Claw Grapple Carriage is known to be one of the most durable systems to date and because of this, the original series is still performing 15 years later.
Alpine cable logging rates
The cost-per-tonne is often a ‘hard-set’ contract price once negotiated and signed so contractors and loggers need to know the business case numbers for grapple carriage use so it can be determined when to use them, how much wood is needed to remain profitable and to plan out block harvesting timeframes. As with all business cases, they’re very situational and when adding in natural environments some assumptions need to be made. We go beyond the assumptions below to ensure you can make a financially informed decision on grapple carriages.
Below is a chart of average alpine cable logging harvest rates in CAN$/T across some countries:
Source: Comparing countries (Spinelli and Visser et al 2014.)
Improved efficiencies with motorised Grapple Carriages generally come down to how the carriage is used, the experience of the operator and how the setting has been planned. Improve efficiencies can be gained through:
Having a well-thought-out plan for motorised Grapple Carriages is paramount. Ways in which planning can provide efficiencies are:
- Reduction of building infrastructure by using smaller landings
- Reduction of environmental clean up of gullies by limiting the volume of slash and debris sliding down the hill
- Utilising one grapple carriage across multiple crews.
The set-up and mobilisation of the motorised Grapple Carriage combined with a hydraulic excavator-based yarder or swing yarder is often more cost effective when compared to larger tower yarder systems due to costs and time moving and setting up – mobilisation. Days of set-up can be replaced with improved production through less downtime.
Methods of logging
The methodology in which a block is harvested will contribute substantially to the level of efficiency. For example, when mixing rigging configurations, angles to pull from, extra machines etc, there are many ways to harvest a block and each contractor will find their most efficient. It is very common for logging contractors to side with methods they are familiar with, however this may not always be the most efficient in the long term. Falcon Forestry Equipment is constantly research new and alternative configurations that can provide greater efficiencies and ease-of-use for customers and enhance their harvesting experience.
Using a motorised Grapple Carriage on it’s own is a very basic way of extraction. When combing with complementary techniques, additional time savings and improved process flows can be seen. Examples:
- Bunching productivity efficiencies – using a mechanised felling system to bunch the stems and overlay onto the cable path for quicker cycle times
- Two-staging with a machine on the hill to pass stems into the grapple, ready for extraction
- Providing lift and utilising gravity for faster speeds down the hill, e.g shot gunning
- Utilising machines on the landing so the yarder can drop its load into a space that is always free of logs, making it easier to pick them up for processing.
- Tethered machines/swing yarders/excavator-based yarders etc
- Productivity: Maximising payload and cycle times
Payload: Keeping Grapple Carriages off the ground (rope wear)
Keeping your motorised Grapple Carriage off the ground not only prevent damage and wear/tear, it also delivers efficiencies and additional cost-savings. An example of a pull dragged along the ground can be seen in the graph below. Reducing the payload by 1 stem might appear to go against the aim of maximising each load, but the benefits are:
- Faster cycle times
- Less wear on the rope
- Less opportunity for damage to the carriage
- Less stem damage
- Quicker turn around times also help with processes on the landing. Smaller amounts more often rather than larger influxes of wood ensure there’s more flow on the landing.
Part 6: Considerations when choosing a Grapple Carriage
The weight of the Grapple Carriage influences not only the lift but also the payload. A larger Grapple Carriage with a larger grapple will have the strength and size to lift larger loads, however the functioning weight of the unit should be considered when the finding the ideal set-up for your harvest settings. This is because a heavier unit will require more deflection, especially when carrying larger payloads. The amount of lift and deflection that is obtainable comes down to how you plan your harvest and the use of rigging systems. Tail spars and intermediate spars are also a way of increasing deflection effectively and safely.
When new equipment is introduced into an operation it’s paramount that it complies with local rules and regulation. One to be aware of is the fire requirements for your local state, region or area you are going to be working in. Fire suppressant and other fire systems within the motorised Grapple Carriage should meet local regulations and requirements. The Falcon Claw Grapple Carriage has country-specific adaptations that include fire suppressants, grapple sizes, radio communication and support to ensure the Grapple Carriage meets the needs specific to your operation.
Durability when working in remote areas is essential to maintaining a productive operation. Some points to consider when choosing a motorised Grapple Carriage are:
- Who manufacturers it? Are they reputable?
- Are parts and servicing options readably available?
- What components are used?
- What level of technical support is offered?
- How long have they been commercially produced for?
In doing the research to ensure you are buying the Grapple Carriage that best suits your requirements, take a close look at the manufacturer of the product you are interested in. How long have they been in business? What is the size of the organisation? Is it well resourced and can it supply on time? Ask for references, especially from other loggers who have used the equipment.
Convenient and efficient access to spare parts is essential for ensuring down time is reduced and productivity remains high. It's paramount to ensure to your distributor has the ability to order parts easily. Some considerations to think about are:
- Are parts readily available
- Does your local distributor hold stock on hand?
- Is there a critical parts list (see example below)
Critical parts are parts which are should be available to contractors and in stock ready to dispatch. The critical parts may vary dependent on the supplier but they are often the 20% of parts of a carriage that are ordered frequently 80% of the time.
An example of critical parts may include:
- Antennas and communication parts
- Filters and others consumables
- Electronic components
- Bearings and other engineered parts
Excavator-based yarder: and excavator that has been fitted with a winching system and tower to operate in a similar way to a purpose-built swing yarder.
Tower yarder/hauler: A purpose-built machine that has a fixed tower and uses a system of cables/ropes to pull harvested trees from anywhere up to 1500 metres away to a landing where the wood is processed. The tower is built onto a tracked or wheeled base that allows it to be moved to ne sites or re-positioned on a landing.
Swing-yarder: Uses a smaller crane-style tower built onto a tracked base machine, which can be swung from side-to-side to enable a grapple on the rope to be dropped down to grab felled trees on the ground.
To find out more, below is a list of useful resources
- Google Scholar - Forest Harvesting Research
- FICA - Forest Industry Contractors Association
- University of Canterbury - Forestry
- Falcon Claw Product Details
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