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**Bunkerbarge** · 26-06-2008

Before progress could be made with the Ben Ain a significant decision had to be made, namely do I use the supplied fibre glass moulding for the quarterdeck superstructure or scratch build a unit.

The first part of the operation was to fit the coamings to the deck opening in exactly the same way as was done with the main hatch opening. Vertical 25mm coamings were fitted and glued to the internal opening beams, ensuring that they remained vertical during the drying process and webs were added at the corners to ensure rigidity of the structure to resist the forces involved with fitting and removing the superstructure.

The supplied moulding had a few issues that required addressing, such as the vertical sides were not straight and vertical so required pulling in with an internal frame, the lower edge was not square to the deck so it had to be dressed up to fit, the forward bulkhead was square to the top so it did not match the angle at the back of the bridge unit made with the deck, the top was flat and not cambered and the moulded detail was not as crisp as I would have preferred with the door openings and plate joints being square to the top rather than vertical as they should be. Combined with this the unit was also a bit on the heavy side so I decided to have a bit of a play around with some plywood to see how difficult it would be to manufacture a unit from scratch.

The unit looks to be a simple enough shape but the ends should be vertical when sat on the slightly angled quarterdeck. This means that the forward and aft bulkheads should also be slightly angled and all the plate detail and door openings should also be vertical when the unit is fitted. I started by making two side plates from the original moulding and marked out the openings. The forward edge was angled to butt up to the bridge unit and the aft edge was angled similarly. Two pieces of 10mm x 10mm stock wood were fitted at the aft edge with 5mm x 5mm supports glued to them to keep them square with the ply bulkhead as the aft edges are curved so will have to be carved from the solid wood. The width of the unit was determined from the moulding and the difference measured from the deck opening determined that the ply bulkheads needed to be 5mm from the coaming so an internal frame of 5mm stock was used to space the sides.

Once the dimensions were settled all the openings were cut from the sides and pieces were made for the forward and aft bulkheads, with a suitably curved top, and the box unit was glued together on the model. The separation of the side bulkheads was set by fitting transverse beams to support the boat decking as well as additional internal frame work and these were used to support half bulkheads with curved top edges which would give the support and curvature for the cambered top deck.

At this point the ply top was cut to shape and the correct position of the funnel opening was determined and cut out with a hole saw and sanded to suit the supplied plastic pipe for the funnel. Once the fit of the top was finalised the top deck was glued down and held to the curved formers until the glue had completely set. When set the unit was finally removed from the model and the quality of the fit to the model determined. From this point on there was no question that the unit was going to be a success and would produce a lighter and more accurate item than the original fibre glass moulding. Internal bracing and stiffeners were added to ensure rigidity and a weir was build around the internal funnel opening from 5mm x 5mm stock wood. The aft corners were rounded off to a 5mm radius by using a sanding block made from sandpaper glued to a piece of board. This enables an even radius along the whole length of the corner and makes for blending the radius to the flat bulkheads a lot easier.

The plastic tube of the funnel was cleaned up and roughened with emery cloth before inserting into the tight fit of the hole in the deck. Once the position was matched to the boiler flue the unit was removed and Isopon resin was poured into the weir to ensure a rigid joint and location with the plastic tube.

The funnel was progressed with the addition of the white metal fittings included with the kit with the position of the fittings being determined from the plan. The ships whistle, cast in white metal, would have to be painted to resemble brass so this was scratch built from bits of scrap brass tube glued together to give a neater unit.

The next structural item to be made was the engine room skylight which was built up from the kit parts with the openings being held open with stays and the white metal fastenings being replaced by M2 screws, nuts and washers to give a much crisper level of detail for the items. The location on the top deck was determined and an opening was cut into the deck to allow through ventilation from the boiler space below when the model is steaming. The internal surfaces were painted with a coat of primer then radiator enamel before gluing the unit to the top of the superstructure.

The bunker opening at the forward end of the superstructure was built up next similarly to the kit instructions with the difference that the transverse beams were laminated from planks, which enabled them to be formed to match the curvature of the camber. The bunker opening frame was glued in place with internal supports for the hatch boards also added. Once this was in place a semi circular plastic moulding was added around the top edge, finishing the deck edge off and following the curved aft corners and the camber of the aft bulkhead.

The final significant part of the unit was to fit the last piece of planked deck on the aft port quarter of the top deck and this was made up in exactly the same way as the other decks had been constructed from 5mm x 1mm planks of lime, spaced with 0.5mm plasticard pieces and the caulking made from white PVA mixed with black powder paint. The final surface was sanded down to reveal the planking below and the deck given three coats of polyurethane varnish.

With the planked deck finished the structure of the unit was considered as complete and the detailed fitting out of the unit could be commenced.