Repairing holes in a plywood boat

(repair, text and photographs by Chris Cleary)

This website last year carried a notice regarding a second-hand Australian Sailfish for sale in an antique store in Geelong. It was a boat from the early 1970’s, the provenance of which, unfortunately, remains a mystery.

It was inspected in late November, and found to have quite a handsome varnished deck.

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When turned over however, ugly holes were revealed in both port and starboard bottom panels in the forward section of the hull.

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Hole in starboard side bottom panel near bow.
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Holes in Port side bottom panel near side chainplate

Despite this damage, the boat was rescued for liberation into the Sailfish paradise on Lake Macquarie in NSW.

The technique to repair this sort of damage is relatively straight-forward. In a painted boat it is easy to get a good aesthetic result. This is less readily achieved on a varnished hull, even with careful matching of the grain of the plywood patches. In a varnished boat, damage such as this has often been the trigger for a change to a painted finish.

The first step was to trim the holes to a regular shape. Be careful to check with fingers the extent of damage on the internal surface of the bottom panels, and expand the hole as necessary so that all damage is removed.

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Damaged sections cut to a regular shape

When the holes were adequately trimmed, tracings were made.

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Tracing of port side hole

These tracings were transferred to a couple of pieces of off-cuts of 4 mm ply that were already pre-coated with a few coats of unthickened epoxy. It is critical that these patches be exactly the same thickness as the panels being repaired, otherwise you will have an uneven finish.

A backing frame for both holes was then made from the same pre-coated 4 mm ply. On the port side the frame was made in two pieces to enable it to be more easily fitted into place. The backing frames were glued with thickened epoxy to the inner surface of the bottom ply, the frames overlapping the perimeter of the holes by about 10 mm. They were clamped in place while the epoxy cured overnight. These frames also protruded into the holes by about 10 mm or so, providing a glueing surface for the patches. They act as butt straps or pads for what are essentially butt joints between the patches and the bottom panels. On the starboard side, a partially exposed stringer acted as part of the backing frame for the patch.

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Starboard side showing backing frame and final patch piece
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Port side showing backing pieces and final patch piece

The patches were dry -fitted to the holes. Note that it is not necessary to have a tight fit. A slight gap provides a space into which sanding filler can be squeezed at a later stage in the repair. This seems to lessen the likelihood of the rectangular patches being discernible through the finished paint job.

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Dry fitting port side patch

The patches were glued into place, covered with pieces of plastic and held in place with gravitational clamps (also known as bricks). The patches and surrounding ply were sanded back after the epoxy had cured.

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Glued and sanded, note minor gaps visible at edges of patch

To allow for final fairing, a generous coat of sanding filler was applied with a squeegee to the patches. I use Bote-cote epoxy, which was thickened with Bote-cote sanding filler powder.

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Starboard side patch coated with sanding filler
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Port side patch coated with sanding filler

It provides a readily sanded surface which can be faired with higher and higher grade sandpaper to a perfect finish. Some areas of the filler coat will become almost translucent with sanding to a fair surface.

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Final faired starboard patch
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And the finally faired port side patch

 

The repair at this point is ready for painting by the boat’s new owner at Toronto on Lake Macquarie.

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Sailfish 150 is back on the water!

This story started in March last year, although I guess you could say it started in the early 1960’s. But a boat that has been hidden away for over 50 years in North East Victoria is out and about again. To read all about the story of the find and the restore and to check out some pictures as well go to the Gallery/Restorations/Sailfish 150.

 

 

Fixing up an old centreboard

More and more Australian Sailfish are surfacing as a result of the renewed interest in the class, and while some will require a full restoration, think Helen and Stanley Crocodile as shown in the Gallery, others might just require a bit of repair and maintenance to get back on the water.

A case in point, Mrs Vicious, winner of the very first National Titles held at Elwood in December/January 1968/69. Hull was in good shape even after years of storage, spars were sound, sail was good and needed only a few minor repairs. As a safety precaution, I replaced the stays as there was no way of knowing how sound they were, having been sailed in the ocean and then stored by the sea for well over ten years.

The centreboard on first inspection was a bit knocked about:

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Apart from the chips along the trailing edge there were some dents and divots along the chord of the centreboard as well.

The first step is to sand it back so you can really see the condition. Now starts the good news, bad news stuff. Sanding back with a painted centreboard is relatively easy, as long as the base paint is sound as it is here, then there is no real concern about ruining the shape of the centreboard; as long as you are not sanding through the paint and into the wood, you can be sure you are safe, that’s the good news. However, in this case, sanding off the red paint revealed that this board had suffered some major damage and then been filled and faired to repair it.

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Notice the amount of filler along the trailing edge at bottom left of the picture. The other side revealed more damage:

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Again a lot of filling and fairing along the trailing edge, even more than I had suspected from the other side, also note the fairly deep scratch marks centre right of the photo below the handle.

OK, so here we are, the board is basically sound, even though there has been some damage, the paint is actually in really good shape, this is a win as it means the entire board doesn’t have to be taken back to bare wood (and filler).

The next step is to hand sand and fair the board, doing your best to remove the worst of any imperfections. If you have to take the centreboard back to bare wood, when it comes to painting I would suggest standing the board on its top end and painting or varnishing both sides of the blade at once to ensure there is no chance of distortion of the blade as one side dries while the other is still bare wood.

For this project I decided to use a roller with a short bristle, this was both a training exercise and an experiment for me, I usually use a brush, but if I am to move into the exciting world of epoxy resin I will have to develop my roller skills. As I hadn’t needed to take the board all the way back to bare wood I was able to paint one side of the board and then the other. Basically, apply paint, sand and fair, repeat until happy.

Two factors affected my paint choice. Firstly, availability, so I used the same paint that I had used to repaint Mrs Vicious’ hull, a well known semi gloss house paint. Which brings me to the second factor – if you are building a new boat, high gloss looks brilliant, really highlighting your boat, but that also means that when doing up an older boat it will highlight every bump, mark and imperfection, which is why I choose semi gloss, or even matt, paint or varnish for restoration work.

Here I did a total of four coats of paint, after the first coat I sanded back with 220 wet and dry (wet), repeated that after the second, after the third I sanded back with 400 wet and dry (wet) and then once I was sure I was happy with the fourth and final coat, I sanded back once again with 1200 wet, being sure to add just a drop of liquid detergent to the water to minimise the chances of scratching.

Here is the end result:

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Is it perfect? Hell no, it’s a 50 year old centreboard that has had some rough times, but the shape has been cleaned up and the chips out of the back edge have been faired in, the scratches in the sides of the blade are smoothed out or removed and it is a clean, usable centreboard for many more years of use.

We hope that this will become part of an ongoing series on Repairs & Maintenance. If you are doing some fix up work on your Sailfish please send in some details and we can run a blog to help out others.