Sjo-Ro

International Six Metre Yacht designed by William Fife, built by Percy Coverdale, Hobart 1934.

Restoration Team

Shipwrights: Simon Sadubin, Tom Coventry Apprentice shipwrights: Hywel Turner, Andrew Rowan

What we did

The restoration of Sjo-Ro started with a sailwith her owner Jeremy Arnott and two of the people who has saved her and brought her back to life 20 years earlier – Gary Ferres and Marni Raprager. Our two apprentices came along to get first hand experience of what is feels like to sail on a boat like this. We noted leaking points, and talked about how the boat was laid out, what worked, what didn’t. This helped plan the final layout with Jeremy’s input. Sjo-Ro was transported to our shed in Mona Vale.  The first job in the restoration was to measure the boat, check for distortion and map the sheer line on both sides of the hull. The usual distortion had occurred around the rig attachment points. The deck was a miss-shapen mess with peaks and hollows. Only the sheer clamps could be saved. The original carvings in the major beams of Lloyds register official number and her registered tonnage were carefully cut out and let into the new deck beams.

It was decided at the beginning of the restoration, to use the same materials as the original build wherever possible. The only exception being where the original material had failed over the lifetime of the yacht. Where new materials were substituted, preference was given to Tasmanian timbers. The deck beams were originally Tasmanian Blackwood, these had suffered the worst of all the original structure. Celery top pine was used as a replacement. No steel, stainless or otherwise was used in the restoration. Sjo-Ro was a showcase of Tasmanian timbers. The only timbers not native to her place of build were the two 35 foot long sheer clamps, specified by Fife to be Douglas Fir.  Fife was well aware that these Australian sixes would be constructed from Australian timbers. His original drawings specified Huon Pine of a density of 35 lbs per square foot to be used in the planking. Little did Fife realise that this would give the Australian yachts a huge advantage over their European built counterparts. Huon Pine is a remarkable slowly grown timber. It contains the essential oil Methyl Eugenol which makes the timber virtually impervious to rot. During the restoration of Sjo-Ro, every square inch inside and out of the planking was scraped back to bare timber and inspected. Not a single plank needed replacement. The only planking repairs required, were in way of an old propeller shaft that had been removed and patched with plywood, and to several old repairs to the outer surface where lesser timbers than Huon Pine had been used.

One of the biggest challenges facing a restoration of this magnitude is retarding the drying out of the hull whilst it is being worked on. After 79 years afloat, Sjo -Ro was sodden. To make things more difficult the hull had been fully splined in the late 1970s. This work was excellent, all the splines were set in Resorcinol glue, but it did not allow much shrinkage of the planking without the danger of splitting splines, or worse, splitting planks.  To arrest this, we started work from each end of the yacht the deck was removed in sections, then he hull could be easily accessed to clean out, repair and prime. Work was completed in bays. As soon as a bay was stripped and sanded, it was given two coats of linseed oil and turps mix to help bulk up the planking. This was consumed at a rate of knots. Once this had soaked in, the interior was primed with three coats of a white enamel primer. This ensured the hull was sealed and would dry out slowly and without stress during her 14 months out of the water.  As much of the thick exterior paint was left on for as long as possible, it was taken back to bare wood in way of frame replacement and repairs as required, and primed with a yacht primer as a temporary seal.

Fairly soon into the restoration a number of hidden issues came to light. Galvanised steel had been used in a number of key rig attachment points. The damage was hidden under layers of repairs, but once exposed could not be ignored. The affected areas were the stem where a galvanised tie rod attached the forestay to the outer stem. Six feet of the stem was removed and replaced. The sheer clamps where the chain plates were attached were also riddled with old galvanised steel fastenings. This section was removed and new section saw, fitted and scarphed into place. The most sobering issue, was that of the condition of the original sawn frames. As per the Fife plan, every third frame was sawn out of solid timber. The Tasmanian builders used Tasmanian Bluegum for this application. They had numerous cracks on sections of short grain, which were symmetrical. This indicated a pair of frames had been cut out of a single curved crook, then sawn in half to create a pair. It was originally thought the frames would be able to be repaired locally, by scarphing new material into the cracked area. Unfortunately, the original frames had not been painted on the back surfaces against the planking. The Huon Pine had survived just fine, but the Bluegum had huge internal rents that were not visable on the outer faces. When we removed the first pair up in the bow, they crumbled, and it became obvious that we were in for complete replacement of all the sawn frames. It also became clear that the splining the planks in the 1970s by her then owner Bob Hamilton, and shipwright  mr x had kept the boat together beyond the lifetime of her original sawn frames. Luckily for Sjo- Ro the smaller intermediate steam bend frames were all Huon Pine. All had survived. Several needed small localised repairs, not total replacement.

This was an interesting moment in the restoration process. We called Jeremy to look at the issue, and he visited the yard to inspect. A restoration project like this relies on a lot of trust. The owner has to trust the skills and workmanship of the boatbuilders, the boatbuilders have to trust that the owner will let them do a proper job. Jeremy was not at all phased by the framing issue. It obviously had a budget implications, but he said it is important that the job is done properly.  Jeremy visited weekly throughout the entire restoration process, and was personally involved in many of the decisions and details of the rebuild. He became an integral part of the process, and soon demonstrated that he had a good understanding of the complex nature of restoring old structures sympathetically. The frame replacement was not easy. Each pair was removed, templates made of the shape, fitted back into the hull, and laminated on a jig.  This was one area where we deliberately deviated from the original materials. For longevity and strength and relative lightness, we decided to use Flooded gum, a mainland Australian species. Its virtue is that it is straight grained, and very strong for it’s weight with excellent gluing characteristics. It would produce strong frames, with no short grain weakness.  All the new frames were primed and then bedded into the hull.  This will make replacement possible again in the future. The main difficulty was we had to work around the sheer clamp. The sheer clamps were kept in place during the whole restoration process. The lightness of the planking made us decide to keep the clamps there to minimise distortion of the hull. It made fitting the new frames tedious. Worked progressed, and it was heartening to see the ends of the yacht looking clean and tidy and strong. It spurred us on to tackle the central sections.

As we completed sections, new deck beams were sawn and fitted into the original dovetail checkouts in the sheer clamps.  This held the shape and braced the ends whilst the next section was opened up. We also decided to construct 4 x ring frames in the hull to take the rigging loads at the forestay, main shrouds and running backstay attachment points. We detailed them to look like traditional frames, floor timbers, hanging knees and deck beams, but they were all bonded together to make stronger framing in these sections. The finished frames look neat and are not instrusive next to the original structure. The two other areas of major reworking was the area around the rudder tube and the sheer clamps in way of the main chainplates.  The rudder tube revealed a hidden surprise. The original backbone was constructed on the ground and pinned together with copper rods. One rod ran right through where the rudder tube hole had to be bored. The remaining ends were locked in place and hidden behind two sawn frames. The offending ends were an early cause of leaking, and by the time Sjo-Ro was bought to our shed, it was barely possible to keep up with the constant flow of water trickling down from the rudder tube and horn timbers.  A modern fibreglass tube was bonded into the repaired horn and counter timbers. This was copper lined with a flange to prevent worm damage, which had started the leaking in the first place.

To complete the structural hull rebuild, all the centreline floor timbers were removed and replaced.  Many of these were replacements of earlier galvanised steel floors, which had been replaced with grown Tea Tree floors. Many of these replacement floors had been badly positioned over the original keel bolts, hiding the nuts, and were a constant source of leaks.  All of the original admiralty bronze keel bolts were removed using a hydraulic jack. All were dezincified, many of the nuts sheared the crumbling threads, and several bolts were cracked. The holes were rebored from 7/8″ to 1″  and new monel keel bolts were made using collected propeller shafts. At this stage it was decided to replace all centreline bolts to ensure watertightness. This time around we took more time to bed things properly and to prime all bedding surfaces. All the keel bolt holes in the lead were counterbored to conceal the heads of the nuts. All bolts were bedded and had an oakum grommet made up underneath the washers as a backup seal. Another major departure from original is that all of the heads of the nails and bolts were cleaned off and epoxy fillers were used to seal them up. Eighty years ago, linseed putty was used which is porous and salt water eventually gets in and slowly corrodes the nail or bolt head.

The deck structure was a modern composite construction. Jeremy had many years earlier purchased a pack of Huon Pine. He had carefully stored it, so Sjo-Ro became the lucky recipient of this scarce resource.  The new deck consists of a ¼” of gaboon marine plywood. The underside of this was lightly v-grooved to replicate the underside of a laid deck. This was sheathed to reduce the chance of water ingress to the ply. A laid Huon Pine deck was bonded over the top of the glass. The seam compound runs full depth to the top of the glass.  Huon Pine is soft, but extremely durable. Many working Tasmanian fishing boats had Huon laid decks that lasted for the life of the vessel – sometimes up to 80 years. All the rig attachment points were replaced with new bronze castings. All the patterns were made as a set, including the rudder hardware, so they all relate in form. Final work consisted of making a new timber rudder and stock as per the Fife drawings. Sjo-Ro survived her first 80 years. We hope that this restoration addresses all of the weaknesses exposed in that time, and it strengthens the original hull to survive a further 80 years of sailing.  

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