How does a Nauticat motorsailer work?
I am looking at buying a 1980s Nauticat 33. I have only ever owned standard sailing yachts with a tiller and a small auxiliary engine. How exactly does a traditional motorsailer like this operate day-to-day, especially with the twin helms and the big engine?
Answer
A Nauticat operates as a true motorsailer by combining a heavy-displacement hull and a substantial diesel engine with a moderate sail plan, allowing you to command the vessel from a fully enclosed pilothouse or an open aft deck. In light airs you rely heavily on the engine, while in a breeze of 15 knots or more you hoist the sails and cut the throttle, using the rig to drive the boat and stabilise the roll.
Dual Helm and Steering
A defining feature of a traditional Nauticat is the twin helm setup. You steer from the aft deck in fine weather and retreat to the heated pilothouse when it gets rough or cold. These boats rely on a hydraulic steering system, using Vetus or Capilano hydraulic rams connected to a heavy rudder quadrant. Turning the wheel at either station pushes hydraulic fluid through copper or high-pressure flexible lines to the steering cylinder.
Engine controls use traditional twin-lever cables. When manoeuvring, you must leave the unused station in neutral, or the cables will bind. If the hydraulic steering feels spongy, the system needs bleeding. A bypass valve sits near the ram. You must crack the bleed nipples while turning the highest wheel (usually the inside helm) to purge the air.
Built Around a Big Diesel
Unlike a standard sailing yacht with a small auxiliary engine, a Nauticat relies on a large, low-revving diesel block. Classic models from the 1970s and 1980s, such as the Nauticat 33 or 44 built by Siltala Yachts, carry a Ford Lehman (90hp or 135hp) or a Perkins 4.236 (85hp). Later pilothouse models from the late 1990s onwards moved to Yanmar engines in the 54hp to 110hp range.
These engines drive a thick stainless steel shaft (usually 35mm to 40mm in diameter) swinging a large three-blade propeller. The setup pushes a 10 to 15-tonne boat through a head sea at a continuous 6.5 to 7 knots. Fuel sits in twin tanks totalling 600 to 1000 litres. Always ventilate the engine space before starting if you have done any fuel system maintenance to prevent explosive fume build-up.
The Art of Motorsailing
Traditional Nauticats feature a ketch rig with a short mainmast and a mizzen mast stepped on the aft cabin roof. Modern pilothouse series are usually sloops. The sail area-to-displacement ratio is low. In less than 12 knots of true wind, a Nauticat struggles to sail at hull speed, which is where motorsailing comes into play.