Building And assembly Of The Hull - Clinker Planking & Lead Ballast

Before the strakes were fitted, I took the opportunity of sheathing across the inside face of the joints in 300 gsm twill woven glass fabric in epoxy. When set, I filled and faired the surface before sanding down flat. I considered it easier to carry out this operation whilst the strakes were laid flat sooner than after fitting. The laying down of the planking required no steaming; it was possible to gradually bend them into position with various clamps and temporary screws fitted with plywood washers beneath their heads. These were set at approximately 100 mm centres. Before fitting the following plank, I found it relatively easy to sight down the hull and plane the bevel on the previous plank after it had been glued down. The planking process progressed steadily without any undue complications. I increased the dimensions of the bilge keels to help hold the hull clear when beaching, these I manufactured in hardwood glued with epoxy and screwed from the inside with stainless steel screws.

It required some careful consideration of how to install the 80k of lead ballast which is designed to fit into the keel. I made a template of the radiused aperture and from that constructed a mould made from the plywood off-cuts; I then stiffened this by screwing down to an off-cut of the material used to construct the jig. I considered that casting the ballast in one pour would be difficult to melt and handle, I therefore created five compartments by inserting aluminium separators to produce ingots of approximately 15 kg. The inside of the mould was then liberally coated with two coats of Sodium Silicate Solution to prevent the mould from bursting into flames. I then constructed a temporary fire enclosure and melted the lead in a cast iron crucible. The combined weight of the lead and crucible was heavy but manoeuvrable. When all had cooled down I simply broke the mould apart to reveal the shaped ingots. I had constructed the mould 2 mm over-size to allow for contraction and cleaning off the face to ensure a perfect fit into the keel aperture; any variations were taken care of by the continuous bed of epoxy in which they were set.  The keel was finally capped and closed in hardwood.  

The purpose built hearth with a fire of wood and coal.

Pouring one of the ingots. I stiffened the aluminium separators by inserting temporary plywood spacers; these were removed before pouring the next compartment.

The lead ballast glued in place ready for closing. I was particularly careful to ensure that there were no cavities within the compartment, epoxy occupied all spaces.

The completed keel before the closing hardwood false keel cap was fitted.