Spider J
Spider J
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Gareth Jones
@garethjones79649Bob Abell 2
@bobabell2Kimosubby Shipyards
@kimosubbyshipyards@garethjones79649Its funny how ideas sometimes come to you by chance, triggered by some random event. I was looking for a bit of brass strip in my scrap box and came across a piece bent through two right angles which was a rejected part of a yacht vane steering mechnism I built last year. It dawned on me that I could use a similar arrangement to drive the tiller on Spider J. My proposed solution uses some of the ideas put forward by Kim and Dave but sadly Bob, no chains.
I propose to mount the servo at the top aft end of the cargo hold where it will be accessible. It will drive a pair of horizontal closed loop push/pull rods which will sit in slots in the frames, just below the deck level. Approximately 40 mm forward of the rudder hinge line will be a vertical shaft carrying a matching pair of levers to which the push/pull rods connect. The shaft will be supported by a pair of plain bearings and extend up through the deck through a hole sealed by a close fitting grommet to keep out any water.
Just above the deck level and directly under the tiller will be another 20 mm lever attached to the vertical shaft. This lever will run fore and aft and at its aft end will support a vertical pin that engages in a slot in the underside of the tiller. I will fit a slotted brass strip to the underside of the tiller to provide a bearing guide for the pin, rather than rub directly on the wooden sides of the slot.
The proposed solution is quite neat, if a bit fiddly. However it avoids any holes in the stern near the water level, gets the levers away from the hull skin and hides the visible parts of the drive mechanism pretty well under the tiller.
Thanks for all the suggestions and ideas, they all help to come up with a solution. I have always found designing things from scratch to be very difficult and a blank piece of paper is pretty frightening. But show me a drawing or suggest a mechanism and I can understand it and develop it pretty well, after all that's been a large part of my job for the last 40 years.
Now I just have to get on and make all the bits and fit them in the boat.
Gareth
Edited By Gareth Jones on 16/01/2015 09:27:13
@kimosubbyshipyardsDave Milbourn
@davemilbourn48782@kimosubbyshipyards@garethjones79649After a few hours spent with a blowtorch, solder, hacksaw, files and assorted bits of brass the rudder and the hinge post have materialised.
The top part needs shaping and trimming to fit a short length of box section in which the tiller will be located. However I wanted to fit the whole thing on the hull before cutting the top to shape.
I am now contemplating a different way of driving the rudder, based on a more conventional pair of levers attached about 15 mm down from the top. These would connect to the rudder servo by a closed loop pair of wires which would run throuh a pair of plastic tubes from the stern to the hold. The tubes would slope downwards as they run aft to minimise the amount of water which might get splashed through the tubes in rough weather or when going astern under motor power. If Spider J starts going astern when under sail it will really be in trouble.
I am just awaiting the delivery of a couple of turnbuckles with which I plan to make the rudder levers and mock up the arrangement before starting to drill holes in the hull and rudder.
Gareth
@garethjones79649Progress on Spider J has been very slow for the last few months, mainly due to a rush on yacht jobs, including fitting radio, rudder servo and sail winches in four different yachts and resurrecting four model aircraft by fitting 2.4 GHz radios in lieu of 35 MHz, with all the associated reprogramming of control throws and mixes.
However the imminent arrival of the CADMA Northern Model Boat Show last weekend spurred me into action and I managed to get the rudder control installation completed in Spider J and the prop shaft fitted. The rudder control is not exactly as I previously planned but is instead based on a couple of 'snakes' fitted between the servo and rudder. They run through the last few frames and the holes had to be drilled using a file in an electric drill, because of the depth of drilling required. This was a bit messy and splintered the ply but it will all be hidden under the deck in the end.
The turnbuckles which form the links are attached to the rudder by a short length of threaded rod and an angled spacer so that the connections to the snake are in line through the rudder pivot shaft.
After fitting the prop shaft Spider J had an outing to Goole this morning to check out the performance on the water. This revealed a couple of major problems in that the brushless motor was very noisy and had fairly coarse control at low rpm. I think the end result is going to be that I will convert to a trusty Graupner Speed 700 brushed motor, assuming it will fit in the space.
However performance of Spider J was pretty good at low power, cruising around very nicely and with a reasonable turning circle at full rudder.
I borrowed Shemarah's ballast weights for the occasion. I think I will also use them in the long term, supplemented with some fixed ballast attached between the frames along the bottom of the hull.
At full power with the brushless motor there was ample thrust and the following couple of photos show it is possible to drive even a model of a 90 year old barge like a hooligan. It makes even bigger waves than Shemarah.
@davemilbourn48782@bobabell2Amy jane September
@amyjaneseptember49770
ashley needham
@ashleyneedham69188@garethjones79649Dave – you're right
Bob – No leaks anywhere
Amy – Glad you like it
Ashley – The rudder will be painted matt black eventually
Thanks to a very speedy delivery from Cornwall Model Boats (ordered Tuesday evening, arrived Thursday morning, Spider J has a new motor. Reverting to a Graupner Speed motor may seem a backwards step to the technophiles but fortunately there was a suitable model in their now much reduced range, which seemed to fit the bill, a Speed 700 BB Turbo, part number G6317.
According to the Graupner datasheet the diameter was 44 mm which looked like it would just clear the keel as long as I made a special mount to get the axis as low as possible. That way I could avoid having to remove and refit the propshaft.
The Graupner performance figures are no load speed on 12 volts, 11600 rpm, no load current 2 amps, max efficiency current 12.5 amps, stall current 43 amps.
A new mount was made up from 6 mm ply uprights on a 3 mm ply base, The diaphragm that supported the brushless motor was cut away and three frames cut down to be flush with the top edge of the keel. The ply base is screwed to 4 bearers that are glued to the frames. A thin piece of card was necessary to shim up the base plate so that the propshaft lined up. Here's a picture of the new motor fitted along with a slaved in Mtroniks 20 amp speed controller.
The installation was taken to Goole on Monday for testing in the usual way and here's a picture of the test set up with Spider J harnessed to the shelter on the pondside. Note the wattmeter connected between the battery and speed controller and tachometer ready on the pond side to read prop rpm.
Unfortunately my 'thrustmeter' would not perform on the day as several of the LCD segments no longer light up so it was impossible to read the correct load value on the fishing scales display. However everything else worked fine so here, for the anoraks among you, are the performance figures.
The boat has a 45 mm diameter 4 bladed brass prop, pitch unknown I am afraid. Power supply was a 3S LiPo battery, only because it happened to have the correct connector for the speed controller set up.
No load performance with the motor just driving the propshaft and propeller out of the water was 1.8 amps at 12.5 volts, 22 watts and prop speed of 12520 rpm.
With the boat tethered, propeller fully immersed in the water and full throttle applied, the current drawn was 16.7 amps at 11.9 volts, 195 watts and prop speed of 9200 rpm. This suggests at full power under load the motor is running at about 75% of the free running speed which is a very good match, particularly since Spider J is not going to be spending much time running under full throttle conditions.
Free sailing was fine, almost as fast as the brushless set up. The installation was much quieter, just a bit of 'Mtroniks whine' from the motor at low speed. Here are a couple of pictures to show you what it looks like.
The next step is to add the mast shroud plates to the inside of the hull and any other fittings that will come through the edge of the deck, before I start to build up the deck sections on the hull.
Gareth
@garethjones79649The front and rear sections of deck have now been added, together with the front and rear headledges, all made from 1.5 mm ply.
The ply strips that make up the walkways along the sides of the deck have been cut out, but before they can be fitted I need to install the brass plates to attach the shrouds and the lee boards. The shroud plates will be glued to the inside of the hull skin and bent inwards so that they are effectively hooked under the top stringer for strength.
I have made a start on marking out all the hull plating using the original shell expansion drawing as a guide.
There are effectively 5 rows of plates each side, between keel and gunwhale. The largest, at full size were around 15 feet by 4 feet so at 1:16 scale they are about 285 mm long and 75 mm wide. I am planning to make the plates from 0.3 mm styrene sheet. Luckily A4 sheets of styrene will be just long enough to get the correct length of plate. Hopefully, where there is some degree of double curvature a bit of heat from a hairdryer should allow the material to be shaped. Each plate will have the rivet pattern applied using a suitable tool, yet to be made up, and will be glued on using epoxy resin. The original drawing will be used as a guide to the fitting of each plate so that there are either lap joints or butt joints between them as on the full sized hull.
The line of the plates was easy to transfer to the sides of the hull but more difficult at the bow and stern. The appropriate end point was marked in pencil and a length of masking tape applied to get the best line around the curved section which should allow the plates to be fitted with the minimum of twisting or double curvature.
The rivets were spaced 3 inches apart on all the lap joints and butt straps and 6 inches apart where they attach the plates to the frames. An unexpected side effect of building the hull with all the frames spaced as on the full sized hull, is that it was easy to mark the position of the frames on the outside of the hull. This will make it straightforward to transfer the position of all the rivet lines on to the individual plates.
When this part of the job is finished I am going to apply for membership of the Rivet Counters Guild.
@davemilbourn48782
John W E
@johnweHi ya Gareth
I have just caught up with this build. Had a good read and thoroughly enjoying it!
Couple of things went through my mind
The first one was, I know you are going to use Plasticard for your plating. At this present moment – I myself am rebuilding my model of the Boston Blenheim which I built in the late 1980s early 1990s and for the majority of the upper works – I used Plasticard for the bulwarks, bridge etc. When I was bringing the model down from the loft I knocked it on the side of the hatch – catching some of the plastic which abruptly shattered into lots of bits and also part of the plastic turned to a powder-like substance.I wont go into too much detail about it.
Anyway, what made me think – is my experience of using the Plasticard as plating on other models – as you are intending to do – which has brought into question the length of life of the Plasticard and all the work you will put into it.
I was originally given a few sheets of printers' Lithoplate (a very thin aluminium) to try that as plating. But, I found, for me to get it to stick successfully to the hull sides (which had been fibre glassed) I had to abrade the contact side of the Lithoplate with emery cloth and I was using Superglue as a bonding agent – as I couldn't get away with using contact adhesives.
Also, my next thought
for your wife's build of the barge; have you thought of double-planking the hull? Using a similar method as these Hatchett magazine people do in their Bismark/HMS Hood/Titanic builds. I myself have used a similar build to this on my last hull (Cargo vessel – Troyburgh). The first layer of planking I did as normal; using fillers to fill any discrepancy in the hull and sanded down. The next layer of planking was put over the top so the planks overlapped the joints of the first layer of planking and this final layer of planking was again sanded smoothly and filled with car body filler. Then instead of using fibre glass and tissue to seal the hull I used Z-Epoxy finishing resin without any matting or any woven materials; painted on as you would varnish.This was allowed to dry and then sanded with wet n dry sandpaper to achieve the desired finish.
Just food for thought for your next build, cos if you do the outer planking neatly you can see and feel it through the Epoxy resin. I have done this style of build on several vessels and they have worked out pretty well.
Last, but not least, you may have already read it – but have you come across the book from Tree to Sea – about the building of a wooden drifter/last of the wooden vessels. It's a very interesting insight into building and it would give you a good idea of how some of the barges/sloops would have been built.
Aye
john
Edited By bluebird on 05/07/2015 18:52:06
Colin Bishop
@colinbishop34627@garethjones79649Colin Bishop
@colinbishop34627@garethjones79649I have now fitted the walkways along the sides of the deck and on one side, the angles where the deck meets the skin plating. The angles are 4 mm Raboesch styrene sections representing the 2 1/2 x 2 1/2 inch section used on the real thing.
Slots have been cut where the shroud plates and mounting for the leeboards will pass through the angles and be attached below deck.
The first few pieces of plate have been added, complete with rivet impressions applied from the back of the sheet. The plates are made from 0.3 mm thick styrene sheet.
To mark the position of the rivets I made up a couple of tools from pieces of 12 mm plywood with pilot holes drilled at the appropriate spacing, in this case 9.5 mm to represent 6 inch spaced rivets. This particular one was made to produce all the vertical lines where the rivets attach the plates to the frames. Where there is a butt joint as in the picture above the tool is applied twice in staggered positions. A smaller, shorter tool has been used to create the impressions of the rivets joining the skins together along the lap joints between frames. Depending on the length of the section to be marked, some of the nails, which are a tight fit in the holes, are tapped back clear of the surface. To ensure they are all aligned I drew a pencil line on a piece of card and tried the tool out, gently bending any of the nails slightly to get them all aligned and equally spaced.
I found it was best to go over all the impressions afterwards with a pointer with a sharp but slightly rounded tip to get a uniform impression at each location. The plates have been glued on using slow setting epoxy resin, held in place with masking tape while the glue sets overnight.
I have had a first attempt at shaping a piece of styrene sheet to one of the double curvature sections on the front part of the bilge area. I taped a scrap piece of sheet in place and then used a hair drier to heat it and try and persuade the sheet to take up the shape of the hull. However this was not a success, I could not get the sheet hot enough. I plan to have another go with my daughters hair drier which is a bit more powerfull, when further supplies of styrene sheet arrive.
John W E
@johnwehello Gareth
I promise I will keep me fingers off the keyboard after this and let you get on with your build. But, I like the new tool for producing rivet marks – another thought is using an old clock gear wheel mounted in an old file hand to produce the rivet marks in the Plasticard.
If you cant get the correct spacing for the rivets what you can do is file the teeth away on the cog between the spacings that you require.
I know I used to get my old clock cogs from a flea market in Shields – I used to go round and there were one or two stalls that had old bits of clocks on.
aye
john
@garethjones79649Progress has been fairly slow over the summer as, although I am retired again, there always seem to be lots of distractions including holidays, gardening, model yacht stuff and lots of other odds and sods. However with the imminent prospect of returning to work again over the winter I have managed to find time to get some more plating done on Spider J. There are now only 17 of the 62 plates left to fix and the general impression can be gained from the picture below.
The method I used has worked quite well apart from the areas where there is a double curvature and I have had to cut some thin triangular sections from the plates to get them to seat reasonably well. I have found that stretching the plate over the curved edge of an old table spoon allows me to form a reasonable degree of double curvature for some areas, without resorting to slitting the plate. Where the plate has been slit I have had to sand down and use some filler so there will be some areas where the rivets will need to be added later.
There has been the odd area where I got a bubble under the plate because the glue did not bond to the hull. I have had to cut these out and fill them, followed by sanding and adding the missing rivets. I plan to try the drops of PVA method to add the rivets required.
Overall the effect of the plating and rivets looks very convincing and the process seems to work well at this relatively large scale (1:16) The thickness of the styrene sheet is 0.3 mm which would be 4.8 mm at full size (3/16 inch) which is close to the thickness used on the full sized sloop. I suspect if the scale of the model were much smaller it would start to look rather clumsy. Here is a section in the bottom of the hull showing a couple of lap joints.
Before I can complete the top level of plates adjacent to the deck I need to add the gunwhale angles around the bow and stern. There are a few other detail parts that mate with this at the front so I am just in the process of making these as a bit of a diversion from measuring and pressing rivet impressions in the plates.
Gareth
Edited By Gareth Jones on 03/10/2015 19:36:27
@amyjaneseptember49770@garethjones79649After a break of about 6 months while have been back at work and occupied with another project I have finally made a bit more progress on Spider J. The hull plating is complete with all the filling rubbed down and the missing rivets added.
The stem, made from 2 brass channel sections soldered together back to back has been added. Its attached by three brass pins into the underlying ply and glued on with Araldite epoxy.
The hawse plates have been added and I have made a start on the rubbing strips, one around the edge of the deck and the first of three pairs on the bows. I have yet to add an angle either side of the bow strips, just waiting for a delivery from Cornwall Model Boats as the ones I bought originally at 3 mm were too small and 4 mm was too big.
The stern has also been plated, including the rudder skeg. Once all the rubbing strips have been added the hull will get its first coat of primer which will no doubt show up all the blemishes and riveting errors.
I have also made a start on the anchor windlass and called to take a few pictures of the appropriate bits of Amy Howson's windlass on the way back from Lincoln this afternoon.
Gareth
Gareth Jones
Bob Abell 2
Kimosubby Shipyards
Dave Milbourn
Amy jane September- Please log in to reply to this topic. Registering is free and easy using the links on the menu at the top of this page.
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