January 31, 2014
Since the last update to the restoration blog there has been much progress on RIPPLE. We now have all of the laminated frames in the midship section of the boat permanently fixed in place.
These have been housed into the keel and then glued using thickened epoxy resin, plus additional bronze screws through the frame into the keel. The reason for the epoxy rather than a softer bedding compound is to stiffen the whole structure since the boat is going to be regularly lifted from the water and will therefore dry out. This is also why we have sealed the timber using epoxy before gluing and fixing the frames in place. The aim is to reduce the fluctuation in moisture content of the timber and so to reduce the amount of movement.
Bronze fabricated plate floors have also been fitted to the frames. The plate floors act to strengthen the whole backbone structure and in effect tie the two halves of the boat together along the centre line.
These Bronze floors have been fabricated from 6mm plate for the main webbing (plate) and then a heavier gauge plate (8mm) has been used for the tabs that sit on the inside face of the frame and keel which take the fixings. The keel to floor bolts have been made from 5/8th bar threaded at each end with nuts made to suit. For the floor to frame fixings bronze coach bolts have been used.
For the construction of the floors the decision was made to go with fabrication rather than casting or other methods. This enabled us firstly to tack weld the component parts together and then to check the fit on the yacht before making any necessary adjustments thus ensuring an accurate fit. Once they had been properly fitted the floors were fully TIG welded before being bolted into place using the 5/8th bolts.
The bolt holes for the keel to the floor joint are drilled using a long auger bit in an air drill and a drilling jig which keeps the drill on track. The underside of the keel is then counter bored to allow the bolt heads to sit below the surface so that they do not interfere with the fit of the ballast keel later on in the build. The tabs on the inside of the frames were drilled off ready to be through bolted to the frames using bronze coach bolts. These are also counter bored on the outside of the frames allowing the bolt heads to sit below flush so that the planking fits to the frames.
Also of note, the old Stern Post, Stern Knee and Rudder Box have been removed and the new sternpost and stern knee have been made and installed.
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