May 23, 2013
By Jack Gunstone-Smith (Second year Shipwright Apprentice)
Since the last instalment to the blog, work has been progressing on “Ripple” in leaps and bounds. The new keel timber has been made from iroko hardwood, using templates taken from the original. Although the original timber was one piece the new keel has been made from two pieces of timber laminated together. So in order to do this I had to first take a template of the original keel timber, as detailed in the previous blog update. Once the templates had been checked and double checked I went on to machine up the timber for the keel, as you may imagine this required more than one set of hands because of the size of the bits of wood so a few of the guys from around the workshop helped out for this part of the process. Once the timbers had been machined I then transferred the outline of the original onto them using the templates made earlier. This shape was then cut out using our large rip saw, which is a bit of an animal, so a certain amount of care was taken when using this machine. The timbers were cut out slightly oversize so that they could then be shaped once they were glued together.
Once the keel pieces had been cut out the faces that were to be glued were cleaned with acetone in order to de-grease the surfaces and get rid of any dust. Any remaining solvent was left to evaporate for a few minutes and then the glue was applied. The two pieces of timber were then glued together using Phenol Resorcinol adhesive, which is a very high strength marine grade glue. The keel timber was then left for 24hrs to allow the glue to cure under clamping pressure. Once the glue had completely cured the clamps were then removed and I began shaping the timber. Using a power plane I planed the timber down to the lines marked from the template making sure that the shape was kept fair and that the edges were left square to the face of the timber for now. I then started to cut the bevels for the plank landing which was rather difficult to do as the angle of the bevel changes progressively along the length of the keel. This was done by firstly taking the bevels at the station marks from the original keel; which had been marked onto a piece of hardboard. And cutting them individually at the corresponding station on the new timber using a chisel and a mallet, these separate cuts were then joined up along the length of the keel.
This process is definitely an art and there is a lot of skill involved in getting it right, so I was very glad to be learning from one of the many time served and skilled shipwrights that work at Berthon, in fact the person that was teaching me served his apprenticeship at the company when wooden boats were still regularly being built. It really is great to be learning skills that are not very often seen nowadays.
Once the bulk of material has been removed using a chisel the rabbet is then smoothed out using a large rebate plane. Once the shaping of the rabbet and the rest of the keel was completed a mortise was then marked and cut into the keel timber at the aft end to accept the tennon in the sternpost. The keel has now been temporarily fitted in place whilst work continues on the frames.
The laminated frames are also coming along very nicely. Over the past week or so I have been making frames and there are now 8 pairs completed ready to be cut and shaped and fitted into the new keel. The frames were made using laminates of iroko machined to a thickness of 5mm. These are then covered with resorcinol glue on all mating faces and bent around a laminating jig; as pictured in the blog. This is then left for the glue to cure. Once the glue has completely hardened the frame is then removed and machined to the required thickness. The frame will later be tapered and bevelled on its outside face to allow it to correctly fit the shape of the planking.