This is about plywood construction not about the monohulls but the boats are interesting. The first is about a 62 footer called “Infidel” built 60 years ago by John Spencer in NZ. Infidel went through many owners but became world famous under the name of “Ragtime” winning the Transpac on several occasions and EG Newport Esanda race etc. What is infidel/Ragtime A 62 x 11.9 foot plywood single chine monohull with a 11 foot deep fin keel. In its latest configuration it has an ex TP52 rig on it which is more than enough power to overload the narrow chine hull that was lengthened to 65 foot and had a modified deep bulb keel with the rudder moved aft. It is now a lot faster than when it was built and launched in 1965.
The interesting part of Ragtime is its over haul in 2020/22. The 2 layers of 9 mm plywood over kauri stringers and frame hull required virtually no repair. John Spencer the designer and virtually single handed builder built the design for Tom Clark, a very successful NZ business man. Spencer was not only a fast builder but was very precise resulting in a watertight structure that lasted for years. The floors that supported the fin keel ran the full width of the boat and were designed to meet the needs of the yacht.
In 1965 Infidel/Ragtime did not meet any know structural classification rules (she displaces 24,000 lbs including its 9000 lbs keel in a period when a “fast” 60 footer weighed 50,000 lbs) and was barred from races like the Sydney to Hobart because it was deemed structural unsafe. The fact its was very fast and could outsail the majority of 1965 Sydney to Hobart yachts had ”no” influence on the SYSC decision to ban it.
So how do NZ people build plywood boats that last 60 years. A hint comes from a guy who is an old hand at building Elliot plywood sailing yachts. He is building his Elliot 1150, a multi chine plywood monohull fast cruiser.
The NZ guy said: “The loaned shed was more than three times the footprint of the boat, but I used all of it. The frames, floors, structure, keel, rudder and decks were built off the boat, the bench saws and other machinery required space to use, and materials needed to stay dry. Neil also had a fork-hoist that came in very handy building a boat short-handed. By mid-March 2021 I was setting up the hull. The cloth was laid over the boat and the rebates for the laps marked and cut in with a power plane. The first real problem presented itself when I started fibre-glassing.
The plywood was gassing badly when the resin went on, forming air bubbles that could not be worked out through the heavy cloth. To stabilise the ply, I rolled on resin and applied Peel Ply to remove the amine blush, a chemical byproduct on the surface of cured epoxy that I had to be mindful of throughout the build.
After laying all the cloth over the boat, marking where the sheets lay and rebating the laps into the plywood, each section of cloth was numbered and rolled onto a pool noodle and stacked away under plastic. I mixed the resin while Neil frantically applied it with a roller and the glass cloth was spread over the wet resin and more resin was applied on top. This would give 99% saturation and air removal, and was further fixed with a rubber squeegee that also distributed any excess resin. Finally, a wide steel roller bedded it down for good. I would then clean up and, as the resin was starting to tack off, a layer of micro balloons filler was generously applied. We did just one strip over the boat per day.
Next, we had to turn the hull over Upright and sitting on a cradle, the boat was starting to take shape. After applying resin to the inside of the hull and removing the blush, it was ready for the keel floors and more structure. After glassing the inside of the hull, it was time for keel floors. These are a series of solid wood beams with an engineered layer of fibreglass covering them. I spent over two months just building this structure. The keel floors and associated structure were built off the boat, glued in place, and then glassed to the hull. This area was painted and then the engine (a 57hp Yanmar) was installed. The foredeck (made in foam glass) frames were lofted on the floor in the same way the hull had been, but in foam. When finished, the foredeck structure was lowered into the boat with the fork-hoist and glued down to the hull.
The message here is in both cases understand the materials and timbers you are using, then appreciate the glues/resins you are using. Experiment and test if the EG plywood reacts to the resins being used. Outgassing can happen in ply and/or foams when layups are being done. If the ply surface is effectively sealed prior to a glass surface layup you will have an excellent chance of having a 60 year yacht. Good tight joints with a minimum of filler also helps a lot.
The jpegs are first of Infidel Ragtime, the second are of the Elliot 1150.
The interesting part of Ragtime is its over haul in 2020/22. The 2 layers of 9 mm plywood over kauri stringers and frame hull required virtually no repair. John Spencer the designer and virtually single handed builder built the design for Tom Clark, a very successful NZ business man. Spencer was not only a fast builder but was very precise resulting in a watertight structure that lasted for years. The floors that supported the fin keel ran the full width of the boat and were designed to meet the needs of the yacht.
In 1965 Infidel/Ragtime did not meet any know structural classification rules (she displaces 24,000 lbs including its 9000 lbs keel in a period when a “fast” 60 footer weighed 50,000 lbs) and was barred from races like the Sydney to Hobart because it was deemed structural unsafe. The fact its was very fast and could outsail the majority of 1965 Sydney to Hobart yachts had ”no” influence on the SYSC decision to ban it.
So how do NZ people build plywood boats that last 60 years. A hint comes from a guy who is an old hand at building Elliot plywood sailing yachts. He is building his Elliot 1150, a multi chine plywood monohull fast cruiser.
The NZ guy said: “The loaned shed was more than three times the footprint of the boat, but I used all of it. The frames, floors, structure, keel, rudder and decks were built off the boat, the bench saws and other machinery required space to use, and materials needed to stay dry. Neil also had a fork-hoist that came in very handy building a boat short-handed. By mid-March 2021 I was setting up the hull. The cloth was laid over the boat and the rebates for the laps marked and cut in with a power plane. The first real problem presented itself when I started fibre-glassing.
The plywood was gassing badly when the resin went on, forming air bubbles that could not be worked out through the heavy cloth. To stabilise the ply, I rolled on resin and applied Peel Ply to remove the amine blush, a chemical byproduct on the surface of cured epoxy that I had to be mindful of throughout the build.
After laying all the cloth over the boat, marking where the sheets lay and rebating the laps into the plywood, each section of cloth was numbered and rolled onto a pool noodle and stacked away under plastic. I mixed the resin while Neil frantically applied it with a roller and the glass cloth was spread over the wet resin and more resin was applied on top. This would give 99% saturation and air removal, and was further fixed with a rubber squeegee that also distributed any excess resin. Finally, a wide steel roller bedded it down for good. I would then clean up and, as the resin was starting to tack off, a layer of micro balloons filler was generously applied. We did just one strip over the boat per day.
Next, we had to turn the hull over Upright and sitting on a cradle, the boat was starting to take shape. After applying resin to the inside of the hull and removing the blush, it was ready for the keel floors and more structure. After glassing the inside of the hull, it was time for keel floors. These are a series of solid wood beams with an engineered layer of fibreglass covering them. I spent over two months just building this structure. The keel floors and associated structure were built off the boat, glued in place, and then glassed to the hull. This area was painted and then the engine (a 57hp Yanmar) was installed. The foredeck (made in foam glass) frames were lofted on the floor in the same way the hull had been, but in foam. When finished, the foredeck structure was lowered into the boat with the fork-hoist and glued down to the hull.
The message here is in both cases understand the materials and timbers you are using, then appreciate the glues/resins you are using. Experiment and test if the EG plywood reacts to the resins being used. Outgassing can happen in ply and/or foams when layups are being done. If the ply surface is effectively sealed prior to a glass surface layup you will have an excellent chance of having a 60 year yacht. Good tight joints with a minimum of filler also helps a lot.
The jpegs are first of Infidel Ragtime, the second are of the Elliot 1150.
