Choosing a Blue Water Yacht – Rudder Type

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Over the last few weeks, Grabau International has taken you through a variety of subjects which encompass choosing the right yacht for blue water adventures. This guide is not written to dictate what to choose, or to supply a comprehensive encyclopedia of every option and variable, but simply a basic explanation of the main options and some guidance on what to look out for. Finding a yacht will always be a battle of your head over your heart, so the purpose of this guide is to give your head some questions to ask in the hope that an amicable compromise can be made with your heart. Part 4 of this guide looks at the question of rudders and steering.

 

Rudders

Yachts use aft-mounted rudders to change direction and to counter the effects of weather-helm (where the yacht naturally tries to turn into wind when pressed to windward). Using either a wheel connected to the rudder stock via a linkage system or a tiller attached directly to the rudder post, the rudder can be turned creating a force of water striking one edge of the rudder blade to turn the stern in the opposite direction.

The type of rudder and fitted to a yacht is often directly related to the type of keel which was covered in part 3 of this guide, and the type of steering is usually dictated by the size and position of the cockpit and space directly beneath or aft of it.

As always, due to the huge variety of yachting pursuits, different rudder types work for different purposes. Those looking to go racing will almost certainly require a high aspect fully-balanced rudder whilst blue water sailors may wish to seek the additional strength and protection afforded by a fully or semi-skegged rudder blade.

Spade Rudder

Where the blade hangs down beneath the yacht and is self-supported by the stock. By moving the rudder stock aft from the leading edge, a spade rudder becomes a balanced rudder.

Balanced Rudder

The ‘balanced’ part comes in by virtue that the axis of rotation is behind the leading edge which means that when the rudder is turned, the pressure of water caused by the yacht’s movement through the water acts upon the forward part to counteract the force of resistance exerted by the larger aft section. The end result is a very light and reactive helm which is perfect for more performance-orientated yachts. Balanced rudder configurations are also usually married with fin keel profiles to further aid maneuverability and performance.

The downsides with spade and balanced spade rudders are the complete reliance upon the rudder stock to maintain structural integrity and the lack of protection to the leading edge of the blade from underwater impacts. Having seen a car drive into the rudder blade of a Volvo 70 (whilst ashore!) and the damage caused to the car whilst no apparent damage was caused to the rudder blade, a well-designed balanced rudder should offer few concerns for the cruising yachtsman.

balanced spade rudder

Balanced rudder on a Frers-designed Nautor Swan

Skegged (semi or full) Rudder

A slightly more traditional and ‘belt & braces’ approach where the rudder is further supported, either at the bottom of the blade (fully-skegged) or midway down the blade (semi-skegged). This will usually be stronger and provide better resilience against impact. The moulded skeg can often help to guide any lobster pot or fishing lines downwards towards the bottom of the blade rather than jamming themselves against the stock. Most fully-skegged rudders are not balanced, so they may take a little more effort to steer, but it is possible with semi-skegged rudders to place the stock far enough aft to provide a balancing effect.

semi skeg rudder

Semi skeg rudder on Malo 46

full skeg rudder

Full skeg rudder

Full keel rudder

Yachts with long-keels, such as Island Packet and most classics, have a rudder which is hinged to the aft edge of the keel, forming a continuous surface. The engine’s propeller is then usually positioned in an aperture at the aft end of the keel, but forward of the rudder blade. This configuration offers immense strength and protection, but the steering can be quite heavy as there is no balancing effect.

full keel rudder

Full keel rudder on Tradewind 35

Outboard rudder

Mostly found on yachts beneath 30ft, outboard rudders are mounted outside of the hull on the yacht’s stern. Most outboard rudders are turned using a tiller rather than a wheel as there is no rudder post to connect the steering gear. Outboard rudders do not require a hole through the hull for a rudder post and are less likely to cause structural issues if damaged, but they are more exposed and therefore vulnerable and it is very difficult to balance them, so steering can be heavier than with a fully-balanced spade rudder.

outboard rudder

Outboard (transom-hung) rudder on Hunter 707 sportsboat

Twin Rudders

Increasingly common on cruising as well as racing yachts as transom-profiles get broader. Twin rudders can be either spade or skeg-hung and can be reinforced to allow the yacht to take the ground when used with a lifting keel profile. Yachts fitted with twin rudders will lose the benefit of ‘prop wash’ to aid maoeuvering astern, but the practical benefits in terms of sailing to windward and (in some cases) drying out make them the only option in many cases.

twin rudders

Twin rudders on a modern Southerly lift keel yacht

Steering Systems

Wheel Steering

Now almost universal on all but the smallest of yachts. Large yachts (or those with broader transoms) will often have twin wheels which have their advantages -they do not encroach on cabin space beneath the cockpit sole, and also allowing clear & unobstructed passage from the cockpit the bathing platform. Wheel steering systems can be connected to the rudder stock through a variety of linkages including rod, cable, chain and even hydraulic steering systems.

twin wheels italia 15.98

Twin wheel steering on an Italia Yachts 15.98

Tiller Steering

Rarely found much above 28 feet unless for racing duties (where they can appear on yachts even as larger as TP52’s), but definitely appealing to those who like the K.I.S. (keep it simple) approach thanks to direct connection to the rudder stock. The downside is that generally the area either athwartships or aft of the tip of the tiller is a ‘no go zone’ to anyone other than the helmsman.

tiller steering italia 9.98

Tiller steering on an Italia Yachts 9.98

Rudder Stocks

These can be alloy, stainless steel or composite. Alloy is popular on high-end yachts as it is strong and light. Stainless is much heavier but perhaps less susceptible to pitting and swelling, but can suffer crevice corrosion. Composite can be found on mass-production yachts or custom high performance yachts. There is no ‘best option’, but be sure to inspect the stock very carefully before embarking on any serious ocean mileage.

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