SB3 Rudder Repair

The owner was concerned about a crack on the forward edge of his rudder, between the two gudgeons.  He wanted a quick repair before heading off to the 2008 Southerns at RCYC.

It's not an area of high stress or pressure, nonetheless...

The rudder is locked into the Workmate vice, with protective padding on each side, an old tea towel on one side and a spinnaker bag on t'other.

First step is to remove the two gudgeon fittings with a pair of 13mm spanners.  Label each gudgeon so that it can be refitted in the correct orientation.
The rust is caused by the washers, poor quality stainless steel, as seen here.
The Dremel grinding tool has been used to open up the cracks and a void is found...
This is an old steak knife (every tool box should have one), good for exploring the void in the layup beneath the cracks.
A rather extensive void in the layup that extends down the starboard side.  Lots of resin in the rudder construction, but not a lot of fibreglass...
After cleaning with an old toothbrush and acetone, a mix of West epoxy resin with microfibres is poured into the wound.
A coffee stick is used to vibrate the epoxy mix into the void, in the same way as concrete is vibrated into a form.  A thinner mix of epoxy resin would have flowed more easily, but the addition of micro-fibres makes a much stronger but less viscous mix and needs to be poked and prodded into the void.
Time taken to do the above:  45 minutes.
The next morning, sanded with 80 grit sandpaper...
An application of rubbing compound, to clear away the rusty marks beneath the gudgeons, has revealed this crack on the starboard side...
Mr Dremel has opened the crack and it seems to be gelcoat only...We will fill this with gelcoat.
To be sure to be sure, a layer of e-glass tapespecifically for epoxy resin, will be applied to reinforce the repair.  Lots of red insulating tape (epoxy resin will not stick to insulating tape) has been applied to define a repair area.

The glass tape has been wetted-out with epoxy resin...

..and here a layer of thin polythene film has been overlaid, and excess epoxy squeegeed out with an old credit card, a poor man's vacuum bag, to ensure a tight yet smooth adhesion. Excess resin runs onto the protective tape.
Time taken to do the above:  30 minutes.
The next morning...peel off the polythene and the red tape, scrub the waxy amine blush off the epoxy with a green scrubbing pad and fresh water.

Purposely did not tape where the gudgeon goes, lest it not fit.
One problem with epoxy resin is that it will turn yellow in UV sunlight.  It would be normal to sand with 120 grit and then apply a coat of white polyester gelcoat.  However, not enough time to do a neat job, so...

A couple of coats of quick dry spray paint, re fit the gudgeons with silicone in the bolt holes and away to Cork.
Time taken to do the above:  30 minutes.