Building the small sailor/cruiser 'Silhouette'
A model of an ' Old friend ' ........A little sailing cruiser that I sailed with my Father and my Sons.
On this page I will attempt to detail the methods used in constructing this model.
The prototype was a 'Silhouette ' class boat built in wood. It was the forerunner of a large number of similar boats built in fibreglass. At 17'6" with a small cabin and a reasonably sized well it gave us all the pleasure of a larger boat economically and being a bilge keel boat was simple enough to transport ( on a very rudimentary trailer, no brakes even !) The shallow draught made it easy to launch
In the absence of drawings start was made by studying old 35mm photographic slides . Fortunately as well as the boat the images showed people, this aided with scaling. The decision was made to build a 1/12th model for display, or possibly later to sail with radio control installed.
As usual, where possible, materials would come from scrap and recovered materials. For example, a building board was fabricated from offcuts of laminated flooring, two pieces being screwed together on a plane surface to provide an accurate work surface..
PVA adhesive is used throughout as, when the model is completed, several coats of sealer and varnish will cover the sheathing and all joints.
Top left. Image from www.boatsandoutboards.co.uk *
Top right. Sketches and half section template.
Bottom. Frames and laminated keel.
* The image of a full size boat is an example of the later fibreglass ' Silhouette ' ...acknowledgements to 'Boats and Outboards ', their site is great for folk seeking to buy all types of boat, trailable or otherwise
The construction sequence :-
Rough sketches were produced indicating plan and chine plus a side elevating showing the sheer and keel lines. Station points were established coinciding with fore and aft well bukheads and tor the cabin front.
From these sketches half sections taken at the station points permitted a skeleton, card half-model to be built onto a wooden ' Backbone '.All the card profiles were extended to a common level, that of the building board.
The sections were adjusted by eye, trimming and where necessary, the addition of card extensions to ensure smooth lines throughout.
The bulkhead and intermediate former dimensions were then transfered to 3/16" ply strengthened by 1/2" x 1/4" blocks to provide a land for the sheathing which was to be1/16" ply.
The spruce strip shear strakes were prebent by soaking on a wet towel overnight then springing round a block for an hour or so. In this way an approximation of the plan curve was achieved although some force was required to persuade them into the eventual 3D configuration of the shear.
Top left. Translated from card
Top right. Keelson and strakes added
Bottom Left. Stern block has been installed for preliminary shaping
Bottom right .Sheathing in progress
The checkouts for the strakes were then cut, allowing for their eventual curvature. The strakes were installed using PVA and pins. The hull would eventually be released from the board by sawing through the extensions of the frames.
The ply side sheathing was checked for fit, and final adjustments to the frames. The sheathing templates were again from Kellogs cornflake packets, easily marked and cut (slightly oversize ). The bow and stern ply was trimmed after the adhesive hardens, as was the shear line.
During construction bow and stern blocks were located by bolts Araldited into their flat face. The blocks somewhat massive (at this stage ) were reduced to the eventual deck level. Meanwhile being removable they permitted ease of sheathing with the 1/16"ply. When removed the blocks were set in the vice for final profiling.
Conventionally the sheathing to the underside of a hull is fixed first, in this case, on the prototype there is a cover fillet fixed along the joint between bottom / side sheathing , allowing the sides to be placed first thus providing a greater ' Land ' or bearing for adhesive at the joint.
The side sheathing installed and the ply trimmed at bow and stern
The next operation was to trim the ply down to the sheer line prior to adding to the length of the foredeck. For this a stretcher cut ro the rough profile of the foredeck camber was installed. A steel rule run across the foredeck block permited the stretcher to be finally shaped ready for the sub deck members ...laying these was akin to building a section of barrel !
Small blocks were added to the frames to support the side deck substructure these were set in place and clamped overnight. The subdeck in deal was added in short lengths, proud of the sheer line to allow the side deck camber to be planed, guided by the top of the side sheathing.
Above. Extending the foredeck to the Cabin fron bulkhead and starting side deck supports
The next operation was to Produce two formers in 3/16" ply conforming to the shape of the cabin roof. These were spaced by longitudinal timbers running above the window openings such that a frame was formed on which the subsheeting for the roof could be laid.This took the form of i/16" planks as shown in the next illustrations. During this operation as with any joint which is not to be permanent a peice of clingfilm in the joint space prevents adhesion.
A lipping of 1/8" dowel was bonded into place around the roof, this was to form the eventual small overhang once the i/16" ply was added over the planking. The ply was glued an pinned into place and once the temporary pins were removed the ply edges were planed to provide the required edge feature.
Top left. Looking lke a hedgehog the first side deck installed..the pins will be recovered for re-use !
Top right. Starboard deck laid, the cabin roof trimed for lipping with 1/8" dowel prior to adding 1/16" ply overlay
Bottom left. .Fitting the lipping, the clingfilm ensures that the roof doen't get permanently fixed in place !
Bottom right. The finished roof with 1/15" ply bonded into position.
Next operation will be to install the well seating ( lockers ) these require careful fitting as there are few straight lines in Silhoutte and each part becomes unique. To obtain an acceptable fit between two bulkheads I use an inside micrometer, a luxury as I posses such an instrument. The same measurements could be made using a large inside caliper or even two pieces of stripwood held together by a number of elastic bands.
Top left. With lockes and bunks installe the opening in the end of cabin bulhead was opened up for access.
Top right. That completed it was time to.' Near demolish ' cabin roof by sawing the access hatch opening.
Bottom left. The main hatch opening trimmed and runners installed. All the pin holes have been filled ready for sanding
Bottom right. The fore hatch in place.Iin each case the hatches were 4 pieces of 1/32" ply laminated over a former
Now it is time to turn attention to the underside of the hull. Silhouette had a central dead weight keel and two bilge keels to allow it to settle onto the sand/mud and provide 'a degree ' of comfort on board. Not always the case at low water when a sandbank could provide an angled berth and an uncomfortable few hours, specially at night !
Top left. The main keel and bilge keels have been installed also the fin which provides for rudder stability.
Top right. The boat will now 'sit on it's own four feet ' as we might say.
Bottom . Trial installation of the rudder on the rudder post.
Painting is for me ' The spoiing stage '. The description was coined by a very good friend, and excellent craftsman who made beautiful rocking horses. He always said that you can be an excellent craftsman yet still spoil a piece by careless painting, or lack of preparation. He was right of course and preparation is the key to success. I have used most types of paint, spraying, aersol driven cellulose and acrylics as well as enamels etc. For models that have to undergo stringent conditions, handling, immersion in sometimes dirty water etc. I still find it difficult to beat Dulux household paints. Of course for exhibition models with fine detail any of the paint sytems are adequate and although expensive, simple to use.
Left. Here the side decks have been painted and the coaming is prebent and ready for fixing.
Right. The coamings are fixed and ready for trimming
The paint job completed the coamings could be fixed. These were prebent around nails driven into a scrap of wood after soaking overnight and drying in the sun. Such small sections of mahogany which have to be three dimensional in their finished location called for care in the glueing and pinning stage. With the plan curve established it was necessary to predrill for the smallest available pins ( Peco track pins ) a 30 thou. drill was employed, with fingers crossed ! Only one coaming piece snapped and needed replacement. To avoid relying on the PVA adhesive to bond to the painted deck a dovetail gauge was used to scrape a groove through the paint so that a wood to wood joint was made. Pinning and springing into the sheer profile followed.
Above left. Fairleads and bow fitting intalled plus the eye bolt for the forestay
Above right. The mainsheet fairleads and the stern cleats set in palace
Further research for detail of the original unearthed an ancient snapshot of my Silhouette, taken in Devon. My wife is patienly wating for me to return from fetching provisions.
The ' Seagull ' outboard engine used on many thousands of small boats of all kinds at the time this picture was taken never failed to start on demand, .............................even in emergencies, thank goodness
Enough history however, back to the model.........
Fairleads for the anchor warp, foresail and fixings for the mainstays were turned up and soldered to small fixing plates. To prevent loss of very small turned parts at the time of parting-off I slip a small length of rod in the tailstock chuck and enter it into the bore so that the turned part simply spins onto that when the cut is complete and does not disappear into the swarf in the tool tray ! Next some minute fittings and bottle jacks for the rigging !
The chain locker hauwse caused a few problems, the barrel was turned fom brass and the cover, which traps the chain once hauled in, was soldered in place. A length of chain with a split link was then inserted from within the barrel, projecting through the retaining slot and the length of chain connected to the anchor. The whole could be then installed.
With the mast stepped a start was made in rigging the boat.Bearing in mind the tendency of wood to warp and bow when cut to slender sections a 40 year old, well seasoned, piece of deal from an old cabinet was selected for the mast. This was cut to the required slender section on the faithful 45 year old bandsaw then tapered. Having decided that, for the present, the model was for display only, sails would not be added. The track in the mast for the sail is replicated only by a 1/16" slot. The roller for the sail hoist was turned on the lathe and installed on a pin through the mast.
Bottle screws in brass were turned, drilled and tapped ( with only a right hand tap available incorporating a two right hand threads! ) This meant that in order to set up the stays it is necessary to pre-wind the stay in an anti-clock fashion such that when the upper bolt of the stay is inserted ino the body of the bottle screw it can be spun clockwise to tighten the stay....a matter of expediency, and calling for fine judgement ! Think about it !
Splices simulating ' Talurite ' cramps are from small diameter copper tube split and crimped to grip the stays. Final adjustment to the tension can be made before final crimping. A great source of materials such as stranded wire for rigging is to be found at http://www.psaeroproducts.com/ Paul the proprieter is a really helpful chap.
Cleats and shackles are fabricated, again from brass. The blocks from .030" brass sheet snipped and ground to shape jig drilled for the pin, tapped with the body flat then bent to the correct form ready for insertion of the plastic pulleys.
Cleats and fairleads are cut and filed to shape from brass offcuts from a previous project.
The sheets are of parachute cord The fairleads have the plastic inserts required to protect the sheets
Above left. Overhead view starboard side, completed model.
Above right. Overhead view port side, completed model.
Below left. Stern view, completed model.
Then it was time to consider the next project ! And the decision made to build a modification of the 'Springer ' a small pusher tug to 1/32 scale. Described elsewhere on this site
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