Catamarans are the fastest-growing fleet in Australia and the most propeller-sensitive boats we work on. Two engines double every gain — and every mistake. Over 1,600 of our documented fitments are multihulls; these are the patterns.
Handed pairs are non-negotiable
Twin installations run opposite rotations — one left-hand, one right-hand — so prop walk cancels and the boat pivots predictably under engines. Supplying cats as matched, handed pairs is standard in our records; if a quote doesn't say 'LH & RH', ask why.
The one-engine economy mode
Long-passage cat sailors run a single engine plus sails — half the fuel, most of the speed. It's also the harshest test of pitch matching: the working engine carries variable sail assistance all day. Self-pitching Autoprops were built for exactly this load profile, which is why the biggest fuel numbers in our records come from cruising cats. Drag matters double too: two fixed props under sail is two buckets — see what you're towing.
The practical checklist
- Drive model first: most production cats are saildrive — spline fitment follows the leg, not the boat brand.
- Symmetry: both sides sized and pitched identically, always.
- Clearance: leg geometry caps diameter; we verify against the drive's documented envelope.
- Racing cats and performance multis: folding Varifolds in handed pairs are the drag answer.
Apply it to your boat
Theory is free; the recommendation is too. Verified by an engineer within one business day.
Start with my cat