Making a Rudder Stock - By Richard Battey - OK 1946

Having been faced with the problem of requiring a lifting rudder due to depth restrictions at my sailing club (Crawley Mariners YC) and being unable to source a rudder stock to convert my existing fixed rudder (basically didn't want to spend £120 for a new one) I decided to take it upon myself and BUILD a rudder stock and you have every right to laugh as I can assure you I am by no means a DIY guru, my wife will vouch for that!

The first task was to establish the size of stock that I would require to be man enough to take what is in effect a relatively small rudder. This was done very crudely by laying the rudder blade on a piece of 10mm marine ply and marking out a sensible size stock to house the main pivot point of the blade. The actual dimension of the stock are:

        H = 270 mm
        W = 200 mm

Once this has been done more accurate markings where made on the ply for the first side of the stock. This was cut to form a template for the second side. The stock would then require a spacer at the top and rear. This was achieved by measuring both length and depth of one side of the top and rear of the stock and cutting from a piece of 35mm x 20mm mahogany both head and rear supports. As you can see from the pictures I cut an angle on the front of the stock, this if anything was to give a slightly more aesthetic look to what is in effect a rather boring looking object!

As one great Blue Peter presenter would say, you should now have both sides for your stock and two lengths of mahogany.

The next process was to epoxy glue both head and rear sections of mahogany to ONLY ONE of the stock sides. I used SP320 mixed with Microballons. (Read manufacturers instructions regarding mix ratios and filler/glue types – most epoxies come with correct mix ratio pumps).

Once the head and rear supports where located and glued they where clamped, excess glue removed and left for a minimum of 24hrs to cure. Once cured I then coated the inside and both supports with a clear coating of SP320 to protect the wood from water ingress. The other inside half of stock was also coated with SP320 and both left to cure.

When cured, the remaining side of the stock was epoxy glued in the same manner described. Once cured and clamps removed you have yourself the basis of a rudder stock.

The next part was to locate the Gudgeon and Pintle. Assuming that both locations on the stern are fairly generic in the class the following dimensions where taken from the head of the now formed stock to the top edge of the pintle: 60mm

It is important to ensure that the correct location/dimension of the pintle/gudgeon is achieved otherwise you could find that when coming to fix the tiller you cant because the head of the stock is below that of the stern decking!!

Having located both gudgeon and pintle on the stock, mark in pencil the depth and width of both. I found that I had to cut a rebate in the ply as the width of the stock was now greater than the width of the gudgeon and pintle, although you can buy wider fittings to suit and pack out accordingly.

Once the rebates were cut the gudgeon and pintle were given a test fitting on the stock and located on the dinghy. It is vitally important that both fittings fit square. Once you are happy with the location I removed both, mixed another pot of SP320 with Microballons applied this to the rebate, relocated the fittings, clamped in position and applied a self tapping wood screw through a fixing point on the gudgeon and pintle where it sat over the mahogany rear block to give extra rigidity. Once cured both fittings are rock solid in terms of fixing. Good stuff is epoxy!!

Now comes the tricky part! Locating the pivot hole! As previously mentioned I had a fixed rudder so I removed the tiller and placed the head of the rudder on the now formed stock. This immediately gave the outline of what I would have to loose in terms of excess wood and what radius I would need if the rudder was to rotate smoothly in the stock. Like all things with wood, and I believe one good carpenter said to his apprentice “check twice, cut once”, make sure when you have marked up what needs to be removed, you are happy before cutting, there's no going back!

Once you have cut the rudder to suite the stock give the exposed ends a coat of SP320 to seal wood. Now it is time to cut the pivot bolt hole. I set mine at a dimension of 135mm x 95mm using an 8mm drill bit; you may want a larger size. Once you have decided where to put the pivot bolt hole carefully drill at right angles to the stock surface (this is where a bench drill comes in handy) if it is not at right angles you bolt will pass through at a very odd angle and cause difficulty in raising/lowering the rudder. It is also vitally important to ensure that the head/leading face of the rudder when lowered is parallel with the inside face of the rudder stock rear block (if that makes sense?). I.e. the bottom/underside of the stock is at 90 deg to the leading edge of the rudder head.

Now that the stock is built, pivot bolt hole located and rudder blade cut to suite, finishes to the stock are required. This can be done by either applying one or two coats of SP320 followed by a couple of coats of one can varnish or do what I did (and this is the illegal bit I'm sure but I did it to give more rigidity plus I love the look of the material) coat the whole stock with epoxy and then sheath both outer surfaces with carbon fibre, let it cure and then apply a finishing coat of SP320 followed by 2 coats of one can varnish (Goldspar – dries quickly!).

(Note when using carbon be very careful when sanding as the fine carbon particles in the dust if inhaled stick to the lung walls and stay there forever potentially causing future illness so ensure you wear protection face equipment when working closely or in a confined space with Carbon Fibre).

Now comes the time to fit the tiller. I decided that the best option would be to re-use the existing tiller fixed to the side of the stock using self tapping wood screws into the head mahogany block. Although you can fit a circular tube to the top of the stock as is the norm.

Now that everything was complete stock finished, rudder in place I was able to get the rudder to be in a fixed down position but had no way of being able to get the rudder to rise automatically. The answer was to drill a hole through the trailing edge of the rudder fit a largish ball block and run some 10mm bungee cord through the block over the stock to a fixing point on the tiller. Now when you pull the rudder down cord the rudder freely lowers to what ever position you want aided by the bungee chord and fixed by a cleat on the tiller and when un-cleated the blade pops straight up as the bungee releases it tension returning into it's set shape when the rudder is up, so no more potential stern removals when coming to shore.

I have and only use this stock and rudder for sailing and have found it to be superb for the location where I sail.

As for cost, well fortunately I had all the bits required to make this equipment, however any good timber merchant will have plenty of ply and mahogany off cuts that I am sure they would give you and the only outlay would be epoxy. Although I had the 1kg SP320 tins, you can buy for £15 the small handy pack of epoxy from any good chandlers. So in all a lot cheaper than paying £120 for a new stock and a lot more rewarding when making it yourself!