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£Ia GREAT BRITAIN MV DAWNLIGHT TOM GORMAN DESCRIBES HIS BUILD OF A DIESEL-POWERED PUFFER AU'nfOR: TOM GORMAN THE DESIGN I first saw the ship 'Raylight' in an article by James Pottinger in the magazine 'Model Shipwright' although I believe that was an expanded repeat of an earlier article published in Model Boats magazine in 1966. The idea of a traditional puffer but diesel engine driven appealed to me. I brought my thoughts to Bryan Ward of Mobile Marine Models and we agreed that if the drawings were enlarged to a scale of 1:32 it would be an ideal model to add to his current range of similarly scaled tugs, lighters etc. Consequently I agreed to build a suitable hull of the model in timber to a quality suitable for using as a plug for hulls in fibreglass and to build a complete model upon the GRP hull to prove the build and provide templates and data to be used to build up a complete set of kit masters. The drawing when expanded and examined, showed certain'areas w<strong>here</strong> alterations were needed to permit easy manufacture of parts for making up a kit, the drawing was then altered to suit and the model was re-named 'Dawnliqht'. Mr Pottinger kindly gave his permission for the use of the drawings in this case. The photographs show the basic build up of the hull, which is the standard plank-on-frame type but with bulkheads in place of frames. Decks were inserted before the hull was sheathed in 3.0 mm thick ply to ensure that the hull would not twist and to add strength. The timber plug needs to stand up to a fair degree of pressure when it is covered in resin and glass cloth as the material gets very hot when it cures and it shrinks over the plug in the process creating a high pressure on the timber. Once the timber hull was finished the surface was brought to a fine degree of smoothness, it needed to be brought up to the finish required for reproduction. The details such as relief ports, anchor pockets, portholes, rope guides and bilge keels need to be shown so that all future hulls in GRP will carry this detail to allow the modeller to complete his/her model correctly; obviously adding such detail in relief needs careful measurement to ensure each item is in its precise location. This detail work can be time consuming. THE HULL I was advised that it would take approximately three weeks between delivery of the plug to the supply of the first GRP hull and this led me to the calculation of costing. The plug had taken almost 80 man hours to build; the master mould would need about a further 30 hours minimum and then the building of the model at about 350 hours all add up to a substantial amount of time not counting the cost of materials etc. Some twenty-five or more years ago I calculated that my initial development costs for a model ship kit were in the order of £3,000; today this must now reach in excess of £5,000 and a manufacturer needs to sell a great many kits to cover such costs before he/she can start to make a profit. It makes one to think does it not? The first hull from the mould eventually arrived and work could commence upon the Quilding of the motor puffer. The hull was first washed in warm water and detergent to remove any traces of the release agent used in manufacture, such release agent would prevent the primer and finishing paints from firmly adhering to the hull. Next all the marked release ports, portholes and rope guide locations were covered with masking tape before they were drilled out and opened up to the correct size. Masking tape was used to prevent the drills from wandering and to prevent the fine gel coat outer surface of the hull from being damaged as the work proceeded, Once all these areas had been completed; the hull was 54 FEBRUARY 2010 www.marinemodelmagazine.com
abraded lightly allover using 600 grit wet and dry abrasive, used wet and the hull was rinsed and left to dry naturally. Rubbing the hull all over with fine abrasive provides a key for the subsequent application of primer and finish coatings. RUNNING GEAR At this point the propeller shaft, 8.0 inches long was inserted through a suitable hole drilled and opened up to suit the outer tube of the shaft. Using a Protoline unit from Mobile Marine Models, the shaft and motor were set into the hull. A mounting for the motor being made from 6.0 mm thick plywood and prepared to accept the motor, this process allowing of accurately aligning the motor, coupling and shaft. Forward of the motor a small platform of 3.0 mm plywood mounted on two blocks of soft wood was installed to carry the M.troniks speed controller and the on/off switch for the electrics. Further forward a cradle of plywood was made to hold the 6.0 volt 10 amp/hr battery lying on its side. All such plywood parts were treated to two or three coats of paint once they were glued down. Note that the 8" shaft, motor, coupling, ESC platform and battery tray were all located so that they could be easily accessed through the hatch opening. Motor, coupling, ESC and battery were all removed after test fitting to allow the hull to be painted. Before proceeding to paint the hull the cast portholes and rope guides were next prepared for fixing, the inside of the hull was lightly abraded in way of all these locations and strips of 0.5 mm thick styrene sheet was attached using a contact adhesive. At the bow area this covered the inside of the bulwarks and allowed easy attachment of bulwark supports cut from styrene and the top rails that were also made from styrene sheet. The cast portholes and the oval rope gUides from the Mobile Marine Models range were next carefully fitted and glued into place with superglue. Main deck supports were made from strips of 3.0 mm thick x 10.0 mm wide soft wood and tacked with superglue along the sides of the hull below the freeing ports at a depth to allow the main decks of 3.0 mm plywood to be fitted flush with the bottom of each port. A second strip being glued over the first to give a thickness of 6.0 mm for mounting the decks, once in place they were secured with catalysed resin for extra security. All the holes in the hull were covered on the inside with masking tape to prevent the spray of paint from spoiling the hull interior. To ensure that no grease or finger marks were left to mar the paint finish the hull was wiped over with methylated spirit and allowed to dry. The whole hull was next treated to three coats of red oxide primer from spray cans, each coating being carefully examined and any imperfections remedied before the next was applied. The paints used to cover the hull were all from Halfords and were of their acrylic car finishes. The hull was then left to harden over a period of four days before it was stood carefully on a flat surface and braced to bring the waterline parallel to the surface of the table. The waterline was marked off with a soft pencil attached to a large try square drawn carefully round the hull. Accurate measurements being needed <strong>here</strong> and all measurements carried out on the basis of 'measure twice, act once'. The lower part of the hull was covered completely with tinder dry newsprint held in place with masking tape; tinder dry to prevent any chance of newsprint marring the paint surface. The upper hull ABOVE: Timber beams across the GRP hull ABOVE: Midships decks laid over beams, ABOVE: Bulkhead aft of midships deck to cerry midships deck beams to be cut away www.marinemodelmagazine.com FEBRUARY 2010 55
Page 4 and 5: ABOVE: Stern of hull showing propel
Page 6 and 7: ABOVE: Stern deck of model complete

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