The DIY Restoration of a Small Yacht: Rudder Surgery(#4)

seb-profile-photo-ytSeb, originally from Portsmouth in Hampshire, is the Sales Supervisor for the Gael Force Marine Megastore in Inverness.

He has agreed to write a series of posts following him and the restoration of his 26 foot, 54-year-old fibreglass yacht.

This series of blog posts so far can be read here.

Estimated reading time: 8 minutes.

BLOG POST #4: Rudder Surgery

I wanted to get the rudder and tiller home so that I could assess their condition and make any repairs from the relative comfort of my shed. As it was a transom hung rudder, removing it was simply a case of unbolting a few brackets and lifting it off its gudgeons.

Despite its substantial size, it wasn’t too heavy, and I was able to get it off and onto the roof rack single-handed.


The Tiller (the “easy” bit)

Despite being heavily weathered, the condition of the tiller ‘only’ warranted renovation rather than a complete replacement.

The first task was to remove all the bits of hardware. The previous owner had bolted various brackets and such onto it that I had no need for. I removed these, countersunk the holes and filled them with a generic teak coloured wood filler.

The old varnish was so flaky that sanding it off by hand was relatively painless, but the teak underneath was very weathered and I would have had to remove a lot of material to get back to fresh wood.


Rather than sand until I had a matchstick for a tiller, I decided to use a teak brightener to give the wood a more uniform appearance and remove the surface mottling caused by weathering. After brushing it on and washing it off, the look was much improved. She was now ready for some varnish!

I used International Schooner varnish, which is an easy to apply, one-part varnish with some UV filters in it, so it was perfect for exterior woodwork.

The first rub down was with 120 grit sandpaper to give the varnish something to key into. I then wiped it down with acetone to remove any remaining dirt and remove some of the oils in the wood which would allow for better penetration of the first coat of varnish.

I thinned the first coat with International’s Number 1 thinners at 20%. This allows the varnish to penetrate the grain of the wood which should prevent any chance of it peeling off in the future.

The technique I use for applying varnish is to brush it on lengthways with firm brush strokes to get the varnish on quickly, then go over it with brush strokes at 90 degrees to the first coating. Finally, I go back over it with very light strokes across the length of the work. In theory, this should get the varnish uniformly applied and remove any air bubbles that may have formed.

The trick is to work quickly so that the ‘wet edges’ of the vanish don’t tack up before you’ve done the whole thing. I’m no varnishing expert though, so if anyone has a better technique, I’m all ears!

The following day it was ready to rub down with 320 grit paper and apply its first coat of un-thinned varnish.




I learned the hard way that good lighting is important when varnishing. After completing what I thought was the final coat, it turned out that there were small areas that I’d missed.

I also think it pays to decant the varnish into a disposable container (paper cups in my case) rather than use it directly from the tin. There’s nothing worse than opening a tin of premium varnish to find a film has formed over the top of it from repeated exposure to the air!

I repeated the varnishing process six times until I was happy with the build-up. I thought the finish looked great!


The rudder: down the rabbit hole I go…

With the rudder safely back home, my first job was to remove all the paint so that I could properly assess its condition.

I wanted to use this ‘opportunity’ as a tester to see which method of paint removal I would use on the hull later on: sanding or wet shot blasting.

I liked the idea of wet shot blasting – using blast media in conjunction with a pressure washer – as I thought it would be the quickest method and give the best finish.

I was wrong…

I’d bought a cheap (£20) attachment for a pressure washer that has a tube going into a bucket of blast media. I used the finest grade of media I could find in the hope that it wouldn’t be too aggressive and damage the surface underneath the paint.


Despite using a petrol powered pressure washer that I had managed to borrow, it was slow going and I found that it would remove chunks of gelcoat before removing whatever primer had been painted onto it years ago.


After 30 minutes of work, the result was a mottled finish that still had some traces of antifouling and plenty of the underlying primer. I’d also managed to cover about 50% of my garden in black sandy stuff. The following pictures show some of the damage it was doing to the gelcoat:



It may have been that I was using the wrong media or that my technique wasn’t right, but the bottom line was that for a DIY’er, it was time-consuming, messy, relatively expensive (the blast media wasn’t cheap) and ultimately, an ineffectual process.

However, it was very good and quick at cleaning up the stainless-steel fittings still on the rudder and at getting into nooks and crannies that would be difficult to access with sandpaper.

After everything had dried out, I flipped the rudder over and retrieved my trusty sanders. I’m a strong believer in having good quality tools and I wouldn’t recommend approaching something like this without a sander that can at least be connected to some form of dust extraction.


The belt sander with a 60-grit paper made such light work of the job that I instantly realised that sanding was the way to go. With the dust extractor running, there was negligible dust, but I still wore a full face mask to make sure I wasn’t breathing that nasty antifouling.

Once the majority of the paint was removed, I used a powerful dual-action orbital sander and hand sanding to finish the job.



That being done, it was time to get down to business. I pulled out the two bolts securing the upper pintle and was dismayed (but not surprised) to find them covered in a yucky brown sludge.


I assumed this was rotten plywood that had been used as a core material for the thick upper part of the rudder, so I drilled out the holes with a 25mm hole saw in order to see how badly rotten the wood was.

I was amazed to find that there was no core material of any kind – just an empty void surrounded by 10mm laminate!


I don’t know if the rudder is the original or not, but either way, I found this construction pretty odd. It did mean that I wouldn’t have to cut out and replace loads of core material though, which was a relief!

My plan was to fill that section with some expanding foam, then cut a core out of the foam which would become a mould for pouring in thickened epoxy. It should end up stronger and more watertight than the original construction.

Onto the main body of the rudder.

It sounded hollow when I tapped on it in any section of the blade which I assumed meant that core material had become delaminated. There was nothing for it but to drill another inspection hole.

To my amazement, there didn’t appear to be any core material in there at all! Just a greasy lining on the inside of the laminate.


As far as I could tell I had three options:

1. Patch up the hole and leave it as it was.

  • As they say, “if it ain’t broke, don’t fit it”. I don’t like this argument as everything on a boat breaks eventually and the job of the owner is to take preventative measures to avoid things breaking when you really don’t want them to.
  • Besides, the boat’s been out of the water for two years but there was still evidence of water ingress in the rudder. If I left the rudder as it was it would quickly fill with water when submerged, giving it a huge mass which I would consider dangerous in a heavy sea.

2. Drill a series of holes in the rudder and squirt expanding foam into them to fill it.

  • I didn’t like this idea either as, due to that greasy lining, the foam wouldn’t adhere to the inside of the laminate and not having inspected the internals of the rudder I would assume that water would still get into it readily.
  • Also, expanding foam from a can is very low density and isn’t really suitable as a core material, any water that got in would wick into the foam and saturate it in no time.

3. Cut out a large section of one side of the rudder, clean everything out, make good the areas of potential water ingress, fill with high-density polyurethane foam and replace the cut section with glassed epoxy.

Option 3 is apparently how professionals would approach the repair.

I think you can probably tell which way I was leaning. Besides, a childish curiosity in me wanted to look inside the thing.

After long deliberations, I decided to take the plunge. I went about marking up a terrifyingly large section – big enough for me to reach all areas of the inside of the rudder blade but with enough lip to let me bevel a 60mm edge for bonding the new laminate.

Then, with oscillating multi-tool in hand, I ripped into the rudder of my boat.

Coming Up Next Time: Join me next time to see what horrors I uncovered and how I go about turning this thing back into a functioning rudder!

If you have any questions for Seb regarding this post, please feel free to comment below.

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