Broken pull down control line

This is the most likely repair you will need to make. The pull down control line is designed to snap if the rudder strikes ground. This prevents more severe damage to the dinghy. 

There is no need to take the rudder assembly apart to effect this repair. In an emergency, if the break is close to the small overhand knot that is used to lock the control line to the rudder, it is possible to simply rethread the line into the small rudder hole and re tie the stopper knot. To do this make a clean cut with a sharp knife in the frayed end. Lightly heat seal the end using a lighted match. This will enable the line to be more easily threaded into the small rudder hole. Re tie the overhand knot at the very end of the line, make it as small as possible and tighten the knot so that it nestles in the hole countersink.

View of rudder pull down line                                                      View of stopper knot

Replacing a broken pulldown control line
This too is a relatively simple repair requiring just a little bit of line threading. You will need an 850mm length of 4mm control line. The pull down line should be a relatively weak line that will readily snap if the rudder strikes an underwater obstruction. This acts as a safety link that protects the rudder / dinghy from severe damage. Excel Pro 16 Plait is a suitable replacement line.  Heat seal the line ends.

Repairing minor rudder damage

The lower extremities of the rudder are easily damaged, usually when launching in shallow waters or when coming ashore and the rudder cleat jams causing the rudder to strike bottom before the cleat is freed. In our case apart from a small nick in the tip of the rudder there was 2 years worth of wear and tear along the bottom edge. A replacement rudder foil will cost in the region of £250 in 2010 but repairing these nicks and worn areas is relatively straightforward and a simple repair procedure is described below.

Place the rudder in a vice, ideally a workbench with an mdf table. Pad the blade as necessary to prevent damage from the vice. Gently rub down the damaged area to remove or smooth any areas that were dislodged or raised as a result of the damage incident. Use aluminium oxide paper of 80 or 120 grade but gently! When the rubbing down is complete the rudder should be smooth and clean apart from the nicks and dents. Make sure that the nicks and dents are clean and free of mud etc otherwise the repair resin will not stick.

There are many products on the market that can be used to repair minor nicks. Most two part fillers will work well, as of course will the car body repair resin together with the fibreglass powder to mix with it. Araldite two part glue can also be used and sticks well but tends to be as bit runny as it is being applied. If you are mixing resin and paste a relatively sticky mix is best.

 Bottom of rudder blade showing initial coat of resin.

Damaged areas rubbed smooth and cleaned of dust etc and resin used to fill the damged areas. The big nick in the very tip required 3 layers of resin, leaving 30 mins between each.

Fill the nicks and worn areas fairly generously and rely on rubbing down to restore the final blade shape. When applying the resin don't worry too much over the look of the job. The main concern is to get a good bond with the rudder surface and to fill all the nicks leaving them slightly proud. Two part resins virtually all set fairly rapidly but most require at least a day or more to set very hard. After the resin has been applied do not attempt to rub down until the resin is fully hardened. I waited for two days.

Hardened resin has been partially rubbed down to the final shape

 Complete the final rubbing down, again using 120 grade aluminium oxide paper with a small wood block to remove the excess resin and then resort to fine grade (240) wet and dry paper with soapy water to do the next stage. The aim at this stage is to have a perfectly smoothly contoured blade just like the original but of course at this point it will look a little messy. For a really good paint job it cannot be emphasised too strongly that time spent on the final rubbing down, getting a blemish free surface is well spent. Finish off the rubbing down with 400 grade wet and dry with the usual soapy water.

Now clean the repaired rudder very thoroughly. All resin powder and remains of soapy water must be removed and finally rub the repaired surfaces over with methylated spirits to remove any greasy finger marks etc. Time to paint.

Car spray paints, or touch-up paints are all suitable. I chose a Halfords White Gloss spray can after comparing all the different 'white' car paints.  In the event this proved a good choice as it was a very close match to the existing Topper rudder blade. Don't be tempted to do the paint job in one session. Initially put on a light spray coat, which may not fully cover out, wait for 15 minutes or longer and then put on another coat. All spraying needs to be carried out with very good lighting conditions, ideally with the light being reflected from the srayed surface towards the operator. It is then easy to see how well and evenly the spray coat is being applied.

If your rubbing down was perfect you will not need to take any further action. However if your spraying efforts caused small runs (spraying too close or too heavily will cause this) allow the paintwork to dry for at least 24 hrs. Longer if you have the patience. When the paint has hardened use soapy water and fine wet and dry paper to remove the runs. Don't worry if the paint becomes matt in appearance. When the paint surface is smooth use rubbing compound or even car T cut polish to produce a brilliant polished surface.

View of the finished job