Fleet balance

Production bottleneck analyser

A harvesting system produces only as much as its slowest critical stage. This shows which stage that is, what the chain can actually deliver, and how much of your committed capital is waiting behind the constraint.

Your production chain

Enter the sustained hourly capacity of each stage in whatever unit you sell — tonnes, cubic metres or hectares — and the capital committed to it. Use realistic sustained rates, not best-hour figures.

Stage 1

Capacity

units/h

Capital committed

Stage 2

Capacity

units/h

Capital committed

Stage 3

Capacity

units/h

Capital committed

Stage 4

Capacity

units/h

Capital committed

System capacity

55.0units/hour

What the chain can actually deliver continuously, regardless of what any single machine is rated at.

Constraint

Truck supply

Investment anywhere else adds cost without adding output.

Capital not fully used

$516,923

Of $1,950,000 committed across the chain, based on each stage's idle share.

Stage-by-stage

Stage	Capacity	Effective utilisation	Idle share	Capital not fully used
Feller buncher	100.0 /h	55%	45%	$315,000
Skidder	80.0 /h	69%	31%	$125,000
Processor	65.0 /h	85%	15%	$76,923
Truck supply← CONSTRAINT	55.0 /h	100%	0%	$0

“Capital not fully used” is an indicative measure of how much of each stage’s investment is waiting on the constraint. It does not account for buffer inventory between stages, shift patterns or the ability to redeploy a machine elsewhere — but it makes the imbalance visible, which is the point.

What this answers

The decision behind the calculation

A production chain delivers at the rate of its slowest critical stage, regardless of what the other stages are capable of. That is obvious stated plainly and routinely ignored in purchasing, because machines are compared individually and bought into systems.

This calculator makes the consequence visible in dollars. Entering each stage's sustained capacity and its committed capital shows the chain's real throughput, which stage is setting it, and how much capital is sitting behind the constraint earning nothing it could not earn at a lower specification.

The result is often uncomfortable and always useful: the machine most worth upgrading is rarely the one a contractor arrives intending to upgrade.

The inputs

Where an honest number for each field comes from

A calculator is only as good as what goes into it, and most of these fields have a value that is easy to assume and a value that is true.

Field	Where the number comes from	The trap
Stage name	Each critical stage in the chain — felling, extraction, processing, loading, trucking. Include trucking: it is a stage even when someone else owns it.	Leaving out truck supply is the most common omission, and truck supply is frequently the actual constraint.
Capacity	Sustained hourly output measured over a full week in representative conditions, in a consistent unit across every stage.	Mixing units between stages, or using peak rather than sustained capacity, produces a constraint that is an artefact of the inputs.
Capital committed	The capital tied up in that stage — machine, attachments and any dedicated support equipment.	Omitting attachments and support plant understates how much capital is idle behind the constraint.

The output

How to read the result

System capacity

What the chain can actually deliver per hour. Every stage above this number has capacity you are paying for and cannot sell.

Constraint

The stage setting production. Capacity added anywhere else changes your costs and not your output.

Capital not fully used

The capital in stages that cannot work at their capacity because of the constraint. It quantifies the cost of the imbalance rather than merely identifying it.

Worked example

A full-tree chain where the obvious upgrade is the wrong one

1A 100 tonne per hour feller buncher, an 80 tonne per hour skidder stage, a 65 tonne per hour processor and 55 tonnes per hour of truck supply.
2The chain delivers 55 tonnes per hour — the truck supply figure.
3Upgrading the feller buncher to 120 tonnes per hour changes system output by nothing at all.

The chain still delivers 55 tonnes per hour, and now carries the depreciation, fuel and finance of a larger machine on top.

The fix here is another truck or a shorter haul, not another machine. That is frequently the cheapest capacity in the chain and the last thing considered.

Avoid

Errors that make the answer wrong, not just imprecise

Leaving trucks out of the chain

Truck supply is a stage whether or not you own it. Chains constrained by haulage look balanced on paper and produce roadside stock in practice.

Entering peak rather than sustained capacity

Peak figures move the apparent constraint to whichever stage was measured most honestly. Use sustained output over a full week in representative conditions for every stage.

Treating the constraint as permanent

The bottleneck moves with haul distance, stem size, weather and truck availability. It is worth re-running as conditions change rather than deciding once.

Solving the constraint with capital first

Landing layout, shift patterns, haul planning and truck scheduling often move the constraint at no capital cost. Those should be exhausted before a machine is bought.

Questions

Common questions about this calculation

How do I measure a stage's sustained capacity?

Over a full week in representative conditions, not over a good hour. Sustained capacity includes the ordinary interruptions the stage actually experiences — repositioning, minor stoppages, difficult ground — because those are what the chain will encounter. A figure taken from a single strong shift will place the constraint in the wrong stage.

What if two stages have almost the same capacity?

Then the chain has two constraints in practice, and the bottleneck moves between them with conditions. That is a more fragile configuration than it looks, because either stage stopping halts production. It is usually worth creating a deliberate margin at one of them rather than leaving both tight.

Should I include stages I do not own?

Yes. Truck supply, a subcontracted stage or a client-controlled landing all set your production just as effectively as a machine you own. Enter them with zero capital committed if you prefer; the constraint calculation still needs them to be correct.

The constraint is a machine I cannot afford to replace. What now?

Work the non-capital levers first: shift patterns, landing layout, haul planning, maintenance scheduling to move downtime out of productive hours, and operator training at that stage specifically. If the constraint persists, the honest alternative is often to reduce capacity elsewhere rather than add it at the constraint — a smaller machine at an over-specified stage releases capital without costing output.

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