Marine diesel engines for Leopard catamarans

Leopard cats are built in South Africa and a very large proportion of them have been through a charter fleet. For an Australian buyer, that history is the whole story.

The usual arrangement

Twin engines, one per hull, predominantly Yanmar saildrive auxiliaries, with Volvo Penta appearing across parts of the range. Sizes step with model.

Check both plates.

The charter fleet reality

Leopard’s relationship with the large charter operators means much of the fleet enters private ownership after several seasons of commercial use. That produces a specific and predictable condition profile:

High hours in warm water. Caribbean, Bahamas, Mediterranean, Southeast Asia. Warm water is the hardest condition for heat exchangers and the fastest for anode consumption.

Enormous low-load charging hours. Charter guests use power. Engines run at anchor to charge, which is exactly the light-load pattern that glazes bores.

Heavy manoeuvring wear. Charter crews and guests manoeuvre on differential thrust constantly. Gearbox clutch packs and control cables take that.

Legs that have worked. Warm water, shore power, and antifouling applied under time pressure at turnaround.

A documentation cliff. Fleet service records are usually good and usually stop at handover. The gap between fleet sale and your inspection is the unknown.

What to check on an ex-charter Leopard

1. Diaphragm dates on both legs. The single most important item.
2. Leg oil on both — milky means the lower seal is compromised.
3. Anode wastage, and what alloy has been used.
4. Antifouling on the legs — copper-based on bare aluminium is damaging.
5. Both gearboxes — engagement speed, oil condition, slip under load.
6. Compression or leak-down, given the charging hours.
7. The generator, which has usually worked harder than either main engine.
8. Heat exchangers, after years in tropical water.

Is it a bad buy?

No — an ex-charter cat that is properly assessed and properly recommissioned can be excellent value, and the fleet maintained it to a schedule that many private owners do not match. What is a bad buy is an ex-charter cat bought on the brochure and the hour meter.

Frequently asked questions

What engines are in Leopard catamarans? Twin saildrive auxiliaries, predominantly Yanmar with Volvo Penta on parts of the range. Check both plates.

Should I avoid an ex-charter Leopard? No. Assess it properly — legs, diaphragms, gearboxes, compression, heat exchangers and the generator — and price the recommissioning honestly.

Why are the hours so high relative to the miles? Charging at anchor. Charter use accumulates low-load engine hours that have nothing to do with distance travelled.

What is the most expensive thing to get wrong? The saildrive legs. Warm-water corrosion on an aluminium casting is expensive, and the diaphragms are a safety item.

Does the generator matter? On a charter cat it has usually worked harder than the main engines. Assess it as seriously.