Rudder System

The two most common rudders that are manufactured are:  

• Transom Hung Rudder

• Thru Hull Rudder

Transom Hung Rudder

The transom hung rudder is, as its name suggests, a rudder that is bolted straight to the transom of a boat. The transom hung housing incorporates a rudder port greasing point and a drilled face for bolting to the transom. For aluminium boats the housing can be manufactured in aluminium and welded to the transom. Our transom hung rudder has Marine Department approval.

The rudder is a single Nickel-Aluminium-Bronze wedge shaped casting. The transom hung rudder can be mounted above or below the water line.

Major advantages of this system are:

The ease of installation and the extra room it creates below the boat (this allows you to either swing a larger propeller or reduce your shaft angle). It improves the steering characteristics of the boat.

Shown below is a transom hung rudder installation.

Custom Built Through Hull Rudder

This type of rudder is for displacement and high speed crafts. In our experience no boat is the same as the next and as such it requires, like a propeller, an individual design that caters for the vessels requirements in service.   Henleys has a vast range of patterns and designs to suit.  If no compromise is to be made you will need a custom built rudder. It is therefore important to be able to deliver what the customer or his boat requires.

Henleys Rudders are manufactured in either stainless steel (ss) plate and stock, ss foil and ss stock or one-piece bronze or ss wedge blade and stock.

Shown above is a bronze cast slotted rudder with stainless steel stock rudder fitted to SMG

Stainless Steel Plate and Stock: The most basic of options, best suited for displacement vessels.

Stainless Steel or GRP Foil with SS Stock: A good option for displacement and planing vessels. Care must be taken in applying the correct foil section to match vessel speeds and also in manufacture of foil as de-lamination can occur over time on high-speed vessels.

Bronze Wedge Section with Bronze Stock: This is our most commonly supplied rudder. Suits mono-, cat and tri- hulls with 12 to 40 knots boat speed. Wedge section works effectively over a wide band of vessel speed range, eg. trawling, mid range and top end speed. Also available in stainless steel.

Transom Hung Bronze Wedge: Developed to facilitate vessels with aft mounted engines on v-drives and to give lower shaft angles by placing the propeller further aft. They also result in better overall steering due to the lever arm effect which is caused by the rudder position being further aft of the centre of the hull pivot point. Smoother running of vessel is achieved due to the prop placement under the transom.

Bronze Wedge Section with Auto Adjusting Trim Foil: This option is designed to dramatically reduce the turning circle of the vessel.

A 2.3 m overall height thru hull rudder
recently manufactured for a USA customer.

Fabricated Stainless Steel Rudder with Tangs

A thru Hull Rudder fitted onto Dennis Connor's (America's Cup) chase boat that was recorded to have the lowest slip ever...

 

Water Flow Diagram

The diagram shows the flow characteristics of water to the different types of rudders. The straight plate design is the most basic option as it simply works as a vertical tab re-directing the flow.

The foil section is the next best option, however as it is working in very turbulent water flow, its true design efficiencies are not realised.

The wedge section is based on the same principle as a surface-piercing propeller i.e. designed to work in turbulent and aerated water. The nature of its design offers consistent water pressure with a better turning circle. A wedge with tab is also an option for ultimate manoeuvrability.

© Henleys Propellers and Marine Ltd - 110 Sunnybrae Road, Glenfield, Auckland, New Zealand

Phone: +64 9 443 5886 Fax: +64 9 443 5892