Part 2.
They (the vents) were originally made using the same plugs as I made and described for the ferry “Northumbrian”. The ferry being built at 1:24 scale and the barge at 1:12, serendipidy had it that at 1:12 they were perfect for the barge. So these were vac-formed. I anticipated being able to have them brass plated…but that was to be not possible according to the various plating companies I approached. I trudged down many blind alleys over many weeks. I even looked into the possibility of using brass powder impregnated into resin (as advertised by a company based in South Shields), but the resulting end-product didn’t look anywhere “solid” enough….and simply adding more and more brass powder simply weakened the resin. In a mild state of despair I went off to confer with the jeweller who made the 2 brass dolphins. He came to the rescue by volunteering to cast them in brass. Although it was streets away from his more usual jobs The 2 part flexible mould he came up with and the resulting wax casting are a work of art in their own right. But there it had to stay for a week as his “proper job” (ie the one that brings in the money) intervened. When I returned one vent had been cast and cooled down and the second one was just about to be removed from the kiln. Then began one of the most interesting “tuition” periods of my life. The “raw” casting can in no way be described as a “pretty thing”. But 5 minutes on 2 sorts of polishing machines produced the articles you see in the attached photo. But he insists on calling them prototypes and wants to have them both returned for melting down and re-casting/polishing etc to get to a standard he’ll be happy with. One of them has a smallish hole in it that gave him an excuse to show me how his laser welding machine works (all £26,000 of it). If only it was available to us mere mortals!
Although each vent is 2.5” tall and 2” across the cowl he was spot on when he guessed each cast unit would weigh in at 40 grammes.
Apart from all sorts of other high-tech stuff he also has a rather large (to my eyes) 3D printer that I may well have reason for him to use on my behalf.
Until I had the vents cast it was pointless doing a stability and balancing test in the water. As I’ve explained, the shape of the hull means that only the centre part of the hull will provide any meaningful buoyancy….so there’s a real possibility that I may have to increase the draught by up to an inch. If, repeat “if” that doesn’t work then Plan B comes into operation.
Thatb basically, is to use the original plastic vents and a resin funnel. Hence the use of the 3D printer. The plastic/resin units would be used when the boat is sailing, and the brass units used when viewed as a static model. Not ideal, I agree, but when needs must etc…….
Let’s just hope that judicious balancing/weight distribution plus the draught increase will make Plan B unnecessary . If that’s the case, then “all” I have to do is repaint the affected bit of the hull and fit the thin red stripe between the blue and the white.
And that’s about it until the afloat testing is done followed by the maiden voyage