November 1, 2013
Over the past few months there has been a slight lull in work on RIPPLE because there have been so many other projects at the Shipyard requiring extra hands. Most significantly, the 67’ Mariflex Challenge Yacht which underwent an extensive refit and has now been handed back to a very satisfied customer. I have also been helping with the FCB2 & Shannon Class lifeboats.
However, since the last blog update in early summer, much has happened. We had a visit from a Devon based yacht designer, Ed Burnett, who has drawn up the new rig and sail plan for RIPPLE. During Ed’s visit he, Brian May, Ian Stables, Stuart Barrett and I discussed the cockpit layout and deck hardware positioning in order to best optimize the boat for both cruising and racing. This discussion led to the decision to extend the cockpit by one frame spacing aft (approximately 14”) which will allow for more crew maneuverability whilst sailing. We also decided to run all of the deck hardware below deck and into the underside of the cockpit half deck; this will leave the boat with a very clean, sleek deck.
Another discussion was about positioning the frames around the mast area that will then bear the load of the mast step and chain plates. These partial “ring” frames have now been laminated (see above), machined up and bevelled to eventually take the new planking, and all of the frames in the midships of the boat are also now fitted awaiting the bespoke bronze floors which are being welded up by Berthon’s engineering department. These frames will then be fastened to the keel timber using bronze bolts and bronze floors in order to tie the whole structure together in the midships area, allowing for the removal of the original stem without the remaining existing structure moving out of position.
The new stem has also been laminated out of iroko hardwood (see time lapse video), and glued together with resorcinol adhesive. Using the advantages of laminating we were able to make the stem in one piece, removing the need for a hooked scarph (meaning also one less joint to cut/fit). We then machined and cut a taper to it running from the top of the stem to about half way down its length.
The new stem will be fitted to the new keel timber using a stepped scarf joint which will also be through bolted using bronze bolts. Once the stem is in place the rabbet will be cut into it to accept the hull planking. This work will partly be undertaken on the shop floor using dimensions lifted from the existing stem and the final fitting/shaping completed with the stem fixed in place.
Above you will note the rather weathered state of the old rudder! So, we decided that we would get on and build the new rudder whilst we were shaping the last of the laminated frames and the stem. The rudder was to be built of oak and we used the original construction drawings to remain as close as possible to the existing rudder that we removed from the boat.
We first made a template of the rudder shape and although we were tempted to change the shape a little we eventually returned to the original profile. We then selected the timber and took it up to the machine shop where we machined it to size. We decided that we would use a tapered tongue and groove joint to connect the blade to the stock. The final fitting of this joint was finished down on the bench before a dry assembly of the parts clamped up together. We then glued up the rudder parts applying to both surfaces. The clamps were positioned to pull the joints up together and also to stop them sliding apart on the glue joint. The whole assembly was also clamped to the trestles to keep it stable.
The shaping of the blade and stock was then undertaken and is a very satisfying job to end up with a well constructed neat finished rudder assembly.
Once the glue had cured we cleaned the joint up and set out the positions of the bolts/tie rods and then drilled them off. Much care and a steady hand are required to ensure that the holes are drilled accurately and remain on the centre line of the assembly.
We then made up our bronze bolts with one end of the bar being heated up and then riveted into a “mushroom” shaped head. This was done to minimize the head size so that we could fit it into a counter bore on the trailing edge of the blade. The fwd, “stock end” of the bronze bar had a thread machined onto it to take a nut. This end is also counter bored and both will have dowels fitted into them. These bolts are sometimes referred to as tie rods as they are effectively “tying” the assembly together.
The next stage is to dry fit the bronze rudder cap and the hinge/pin assemblies. Some of which will need to wait until we can position onto the boat.
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