by Rick Buchanan, Hobie Hotline March/April 2009 (Volume 38, Number 2), pp 14-15
Have you ever been rigging your Hobie in a parking lot, and accidentally let go of your rudder (or dagger board) at the wrong time, only to have your friends tell you a basketball bounces better? How about when you’re out racing and you jibe (like I did) only to bounce your tiller on the trailing edge of your kicked up rudder, chipping the fiberglass? Or, how about when you’re racing, trying to sneak up on someone, only to have them hear you coming, because your rudders are humming the Star Spangled Banner?
Now what do you do? These are relatively easy repairs you can do yourself. It doesn’t take high tech tools to make these repairs. It does take a steady hand, and some patience. Take your time, don’t rush a repair. Remember to wear protective clothing; long pants, shirt, eye protection, gloves and a good quality filter mask.
So, let’s take a look at some ways I’ve found to do these types of repairs. Keep in mind there are always going to be other ways to skin a cat.
The following photos show a dagger board and rudder, each with totally different problems to fix. In photos [1] through [3], we have a damaged trailing edge on a Tiger dagger board which is very thin, similar to a Tiger rudder. Photos [4] through [15] show a Hobie 16 rudder which hummed, and vibrated excessively.
Tiger rudders come from the Hobie Europe factory with a sharp (ready to shave your face) trailing edge, which is very thin and fragile. If you grab the edge with your fingers, you can actually flex the blade. If you drop your tiller on the edge while jibing you will most definitely chip the fiberglass. In the photo below left, you see small chips in the glass with some Kevlar fiber protruding. Kevlar is difficult to work with because it fluffs up if you sand it. We’ll replace it with a pre-made fiberglass strip (for details on how to make this, see the “This Old Boat” in the March / April ‘08 HOTLINE). Photo [1] shows a Dremel tool with a cut-off wheel being used to cut a thin groove into the blade so that the fiberglass strip can be inserted, filling the damaged area. Photo [2] shows how to mark the end fiberglass strip for trimming. Test fit the strip as shown in photo [3]. Next, tape off the surrounding surfaces to protect the blade from resin runs and sags during the repair. Use a quality polyester or vinylester resin, mixed with some West Systems #406 Colloidal Silica to a soft butter consistency, to fill the slot. Insert the fiberglass strip and let cure. The inserted glass can be trimmed to fit. Once trimmed, and faired, using Formula 27 (a polyester based filler), a finish coat of gelcoat sprayed on, and buffed, should have it looking new again. West System products and Evercoat Formula 27 are available at West Marine stores. Spraying gelcoat was covered in the July / August ‘09 issue of the HOTLINE.
The Hobie 16 rudder shown here in photo [4], had a trailing edge with a width of about 3/32″, the entire length of it, causing severe humming and vibration. To begin this repair we use an inexpensive “rack” made from some spare pieces of 2 x 4 lumber [4], to hold it firmly in place. Be sure to pad the rack with a soft material to protect the finish. Set the blade and rack on some saw horses, or other work surface which is at a comfortable height for you. As with any repair where you plan to sand or grind fiberglass and resin, remember to wear protective clothing; long pants, shirt, eye protection, gloves and a good quality filter mask. Next, using a pneumatic angle diegrinder, cut a groove into the trailing edge [5] and [6]. After the groove is made, tape off the surrounding surfaces [7] to protect the blade from resin runs and sags during the repair. Using long strands of fiberglass, in this case some woven roving strands [8], we’ll fill the groove we made. First, holding the strands at each end, dip the strands into a small mixing container filled with an adequate amount of catalyzed resin. With the strands of fiberglass saturated with resin, carefully work them into the groove using a back and forth motion. Let the ends of the strands protrude from both ends of the groove as seen in photo [9]. Add enough strands to build up the area larger than what you want the finished work to be as seen in photo [10].
Once cured, use a jitter bug sander [11] to shape the edge to your liking [12] and [13]. If desired, the new trailing edge can be finished off with some new gelcoat [14] and [15].
Another thing that I’ve found helps this repair, is to use 220 – 320 grit sandpaper, held like a “taco shell” between the fingers, and then run along the full length of the rudders trailing edge. This sanding is done on the last ½ to ¾ inch of the rudder. Sanding marks which show this can be seen in photo [12]. By doing this you will eliminate practically all vibration and humming.
When you’re not sailing your Hobie and it’s packed away on the trailer with the rudders crammed into your cat box, protect them from damage. The Hobie Cat Company, through their authorized dealers, has some excellent rudder covers available.
