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COMPOSITE EMERGENCY RUDDER SYSTEMS

GCRC has developed a mold for building emergency rudder blades. GCRC's Denis Fraisse and Doug Frolich (Marshall Yacht Design) designed the system which can be adapted to any transom, no matter what angle or how complex, on boats up to about 55 feet. The blade slides into a carbon cassette for maximum ease of deployment. The top of the blade has a simple rectangular profile. We finish the top with a profile for tiller-based steering or adapt the cassette for line-based steering. The cassette attaches to the gudgeons which can be either composite or metal.

the blade and cassette

The blade is built and vacuum-bagged in a 2-part composite mold with a custom laminate schedule based on the yacht size, displacement, and righting moment. The blade has an integral carbon spar running down the entire length. We also laminate a return flange for maximum gluing surface between the two halves. We use high-strength epoxy adhesive designed for secondary bonding to unite the two halves.

Full Size Blade Dimensions: 300mm wide by 1850mm long
(Blade length can be modified)

To make the cassette, we laminate a carbon sleeve using the blade as a mold. Dimensions vary according to yacht size and transom characteristics (spacing between upper and lower gudgeons). We then laminate the carbon composite bands that fit into the transom gudgeons and close off the back of the cassette with a band of carbon / kevlar to insure the blade can't slice it open upon impact. In the picture to the right the cassette is 445mm long.

The entire system weighs between 12 and 18 kg (26 - 40lbs) depending on the size and whether you choose metal or composite gudgeons.

Gudgeons

We build the gudgeons with carbon, G10, and stainless steel ball-joint swivel bearings. Gudgeons can also be made out of stainless or aluminum. The use of the swivel bearings greatly simplifies instalation, since most transoms have curvature, making the alignment between the upper and lower gudgeons difficult. In some cases the upper gudgeons can be bolted to the cockpit floor. For really shallow transoms, or extremely angled transoms, we move to a tri-pod structure (see below).

Steering

Not all boats have enough clearance in the transom area to use an emergency rudder system with a tiller. For boats requiring line steering we can incorporate a stainless padeye or a composite padeye on the cassette sides for attaching lines. Line steering has some advantages over tiller type steering, like the ability to mount the system on centerline since the backstay is not an issue, and a faster deployement than tiller steering in many instances.

Transom Profiles

GCRC builds attchment systems for virtually any transom type. For "stepped" or complex transoms that do not have a flat profile and/or do not allow for sufficient separation between the upper and lower attachment points, GCRC has developed a system of carbon tubes and stainless steel ball joints that adapt to angled surfaces.

(More pics & details) Open transom with cockpit floor-mounted upper gudgeon. The lower gudgeon is built-up to support the up / down forces on the blade
j109 (More pics & details) Shallow transom with tripod attachment system using compression tubes. This method is adaptable to various transom types.
Example of composite gudgeons on a J-125 with an angled transom with enough spacing between the upper and lower gudgeons
(More pics and details) Example of highly customized attachment system. Customer had aluminum tracks bolted to the transom for a previous metal e-rudder system.
   
   
   
   
   
   

 



Example of a complete system on a Beneteau First 40



Upper gudgeon bolted to cockpit floor with
swivel bearing



Lower gudgeon with swivel bearing

 



Angled transom top gudgeon


(example of a simple system with metal gudgeons and a
removeable carbon tiller made of rectangular
carbon tubing)


(the blades are vacuum-bagged in a
2-part composite mold)