Fuel and range planning for the Lombok–Gili–Komodo corridor comes down to one discipline: size tankage for the longest real leg at service speed, loaded, into weather — then add a hard reserve of at least 25 percent that the schedule is never allowed to spend. The corridor’s legs are unforgiving in exactly one way: fuel stops are few, informal and occasionally dry, so a boat that arrives at its plan’s edge has no margin to buy back. Get the arithmetic right at design stage and the tanks are simply steelwork; get it wrong and every eastbound season becomes an exercise in jerry cans.
The corridor’s real distances
Planning numbers, in round nautical miles, for the legs that matter:
| Leg | Approx. distance (nm) | Notes |
|---|---|---|
| Bangsal – Gili Trawangan | 4–6 | Short shuttle; cycles, not range, drive fuel |
| West Lombok – Labuhan Lombok (around the north) | 60–70 | Exposed north coast in monsoon swell |
| Labuhan Lombok – Moyo / Sumbawa Besar area | 50–70 | Alas Strait currents at the start |
| Moyo – Bima / east Sumbawa | 90–120 | The long middle; few reliable fuel points |
| Bima – Labuan Bajo | 70–90 | Sape Strait tides demand timing |
A Lombok–Labuan Bajo delivery therefore totals roughly 280–350 nm depending on routing and stops — a passage profile covered in build in Lombok, cruise to Komodo. The design case is usually the Moyo–Bima stretch: plan it as a 120 nm leg into a head sea and the tanks will be honest everywhere else.
Burn rates you can actually plan with
Fuel burn follows power, and power follows speed and load — which is why range planning begins with the same numbers as engine sizing, covered in sizing horsepower for a Lombok-built boat. Working planning figures the desk uses:
- Displacement wooden hull, single diesel (100–150 hp): 8–20 litres/hour at 7–9 knots — roughly 1.5–2.5 litres per nautical mile for a loaded 15–20 m hull.
- Semi-planing fast boat, twin outboards (2 × 200–300 hp): 80–160 litres/hour at 20–25 knots — 4–7 litres per nautical mile, tripling and worse into a head sea when the helm holds speed instead of trimming down.
- Small cats and efficient hulls: meaningfully better per mile at displacement speeds; the advantage erodes as speed rises.
Two corrections turn brochure figures into corridor figures: add 15–20 percent for hull fouling and tropical service, and plan currents honestly — the Alas and Sape straits run hard enough to swing a slow boat’s effective speed by two knots either way, which on a 100 nm leg is an hour of extra burn or a free gift, depending on your tide table.
Sizing and building the tanks
Work the requirement backwards: longest leg × litres-per-mile at loaded service speed × 1.25 reserve = minimum usable capacity. For a displacement cruiser running Lombok–Komodo seasons, that typically lands at 1,500–3,000 litres; for a fast boat intended to make the same trip in hops, 800–1,500 litres split across tanks. Build decisions that matter as much as the number:
- Multiple tanks with a transfer and selection manifold — one contaminated tank must never mean a dead boat mid-strait.
- Baffles in any tank over a few hundred litres; free-surface fuel is a stability tax exactly when the sea is worst.
- Placement near the centre of buoyancy, keeping trim constant from full to empty rather than nose-heavy at departure.
- Primary filtration with water separators, twinned and valved so filters swap underway — the single highest-value fuel component in Indonesia.
- Real sounding or calibrated gauges. A stick and a calibration table beat a bouncing float gauge; the crew must know litres, not “about half”.
Tank material, mounting and inspection access are structural specification items alongside everything else on the custom boat build page.
Fuel quality: the corridor’s quiet hazard
Diesel and gasoline along the route come from harbour depots, drummed supply and jerry-can retail of varying provenance. Water and sediment are routine, especially from drums. The defensive habits that keep engines alive: fuel through a funnel filter every time drummed supply is used, tanks kept full overnight where possible to limit condensation, separators drained daily on passage, and a spare-filter stock sized to the trip, not the shelf. For liveaboards running guests east in season — the operating pattern of the liveaboard programmes — a fuel-polishing loop is a defensible luxury that pays for itself the first time a bad drum arrives.
Reserves are policy, not arithmetic
The 25 percent reserve only exists if the operation treats it as untouchable: a written rule that the boat refuels before the reserve is entered except in emergency. Crews under schedule pressure will spend margin unless the owner has made the margin sacred — which makes fuel policy part of crew training during commissioning, and part of the standing orders the desk writes into handover documentation. Range is a number; reserve is a culture.
Design the tanks for the corridor’s longest honest leg, filter as though every drum is dirty, and time the straits instead of fighting them — that is the whole doctrine, and boats specified this way simply do not have fuel stories to tell.
Frequently Asked Questions
How far is it from Lombok to Labuan Bajo by boat?
Roughly 280–350 nautical miles depending on routing and stops, broken into legs: around Lombok’s north coast to Labuhan Lombok, across the Alas Strait to Moyo or Sumbawa Besar, the long 90–120 nm middle to Bima, then 70–90 nm through the Sape Strait to Labuan Bajo.
How much fuel does a fast boat burn per nautical mile?
A semi-planing hull on twin 200–300 hp outboards typically burns 4–7 litres per nautical mile at 20–25 knots — and substantially more into a head sea if the helm holds speed. A displacement wooden hull on a single diesel runs nearer 1.5–2.5 litres per mile at 7–9 knots.
What fuel reserve should be designed in?
Size tankage for the longest real leg at loaded service speed, then add at least 25 percent that operating policy treats as untouchable — refuel before entering the reserve except in emergency. Fuel stops along the corridor are few and occasionally dry, so margin cannot be bought back mid-leg.
How do you protect engines from dirty fuel on the corridor?
Assume every drum is dirty: funnel-filter all drummed supply, fit twinned water-separating primary filters valved for underway changes, drain separators daily on passage, keep tanks full overnight against condensation, and carry a spare-filter stock sized to the trip rather than the shelf.