How much does marine diesel cost?
I'm trying to budget for my first season with a diesel inboard. How much am I actually going to pay per litre at the marina, and is it cheaper to just bring cans from the petrol station?
Answer
UK marine diesel at a coastal or inland marina costs between £1.30 and £1.80 per litre, fluctuating with global oil markets. The final price depends heavily on your declaration of how much fuel goes towards propulsion versus domestic heating and power.
The 60/40 Duty Split
Private pleasure craft in the UK can still use red diesel (gas oil), but owners must pay the correct duty. HMRC requires a declaration of what percentage of the fuel is for propulsion and what percentage is for domestic use. Domestic use includes running an Eberspächer diesel heater or a generator to charge house batteries.
Propulsion fuel attracts the standard fuel duty of 52.95p per litre plus 20% VAT. Domestic fuel benefits from a rebated duty rate and 5% VAT. Most marinas default to a 60/40 split (60% propulsion and 40% domestic). If the marina buys wholesale red diesel at 80p per litre, applying the 60/40 duty and VAT split brings the final pump price to around £1.40 per litre. Buyers sign a simple HMRC declaration form at the marina office upon payment.
Skippers are not locked into the 60/40 split. Liveaboards who barely leave their berth during winter can legally declare a 10/90 or even 0/100 split. This drops the price per litre, saving 30p to 40p per litre on a heavy domestic fill.
Marina Pumps vs Jerry Cans
Filling 20-litre jerry cans with white road diesel at a supermarket forecourt is an alternative. Road diesel currently costs around £1.45 to £1.55 per litre. Marinas apply a markup to their base red diesel price, making forecourt white diesel cheaper than marina red diesel for a 100% propulsion declaration.
Older marine engines, such as a 1980s Perkins 4.108 or a Ford Mermaid, run well on white road diesel (EN590) due to its high cetane rating. Hauling heavy jerry cans down a moving pontoon is backbreaking work and introduces a serious risk of dropping fuel into the water. Spilling diesel in a marina incurs environmental fines and cleanup costs. Always use a high-quality jiggle siphon (shaker siphon) rather than pouring from a spout to prevent splashes.
Regional Pricing and Bulk Buying
Location dictates the price. Marinas in high-demand areas like the Solent, Poole Harbour or Windermere charge a premium, pushing the 60/40 pump price above £1.65 per litre. Inland waterways and roving fuel boats on the canal network are generally cheaper, hovering around £1.25 to £1.35 per litre.