A Guide to Planking Miniature Boat / Ship Hulls by robinb (Robin)
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I find it sad that many model Shipwrights rush the hull to complete it when surely it is the most important part. What is the point of producing a beautiful model spoilt by inadequate planking? The following article is an attempt at explaining the correct way (in my humble opinion) of planking boats or ships, as basically the principles are the same. The object is to plank the hull with fair and even planking. I am assuming keel and or frames / moulds are set up and faired in readiness.

1. General Ground Rules
   1. Planking is not parallel, every plank or strake has its own shape
   2. No stealers should be necessary
   3. Planks are shaped to each plank run, not necessarily tapered
   4. No planks should have feathered ends, if less than 45’, ends should be shaped into king plank
   5. In Clinker work planks cannot be edge set or forced to shape, this will result in buckling off moulds. Some can be done in Carvel work but only if planking is fair.
   6. How do we arrive at correct planking? This is the fun bit!  The run of planking has to be worked out first, not left to chance. This work in larger yards would be would be carried out by the Shipwright foreman. In the smaller yards by the shipwrights.
   7. I will take each planking type in turn. I will say at this juncture that I prefer to build small open boats as all work can be seen, whereas in fully decked ones the interior work is not visible. I use lime for planking and fittings because the grain is very dense and tight; most woods available have too much out of scale grain, which spoils the effect. Apple is used for ribs. (Correct term timbers) as it can be cut very small usually about 33thou x 55 thou or thereabouts depending on size specified and because it will bend easily in fair curves without breaking. I have not as yet steamed any timbers or planking in any of my models. I believe that timber sprung to shape as far as possible makes for a far stronger construction.
      1. You will find that the planking at the turn of the bilge will be almost straight, turn down below the bilge, and rise up to the sheerline above the bilge.
      2. I am working for the sake of this article at a scale of ¾” to a 1ft ( 1 to 16 )
2. Clinker-planking
   1. Our objective is that when looking at the boat from the side all the planks appear an equal width at each station; planks can be wider below the waterline, decrease around the turn of the bilge then widen again up to the topsides. In addition I was taught that the plank below the sheer (the last plank) should be wider by the size of the rubber. (This is the shaped wooden moulding to protect the planking) The Sheer plank would be reduced by the land width because of course it’s not needed – so again the planks all appear to be of the same width.
   2. The moulds have to be divided up into the number of planks. The best way to do this is to wrap a piece of card around the center mould initially, from the keel around to the sheerline, and mark the sheerline in with a ‘pricker’ such as a needle in a pin-chuck, pencil lines are too big. Lay this ‘mould card’ out flat and divide the distance with proportional dividers or a pair of screw dividers; the planks at the center should be approximately 5” wide This will give you the no of planks required, about 8 in a 14’ boat, 14 in the case of a 27’ Naval whaler.
3. Garboard planks
   1. Use a piece of stiff card (about 1/2” wide) to offer up to the keel wrap it around so that it lies flat on every mould or frame and ‘spile off’ (as we used to say) the first plank or ‘garboard’. This can be done using compasses, set to the widest gap from the keel and marking at the mould stations. You will find that you need to bevel the fore end to fit to the shape of the keel; the aft end will overlap the transom. I use rubber bands or modified clothes pegs to hold the card in position, while being marked.
   2. Once you have a good fit, mark off the plank width on the card at the center mould. Use a steel rule to mark-off from this center so that the top edge of the plank is straight, parallel to the keel. If curved as in a whaler keel mark off so that the ends are equal distance and cut it off with a scalpel. Clip it back into place with clothes-pegs or rubber bands; sighting from the side look at the top edge of the plank (‘top’ edge because we are working from the keel towards the sheerline): you will see that the ends of the plank appear to curve upwards.
   3. Lightly mark the template with a pencil at the stem and stern / transom to show a straight line again viewed from the side.
   4. Take off the template and lay it flat, clip the batten around the top edge, to approx. 2” scale size from the ends. Bend the batten down to the pencil marks and mark around; checking that the batten is in a fair curve no sharp humps or bumps, cut off this surplus.
   5. You will find that the ends of the garboard now curve downwards and that you have the correct shape; try it on the other side to see how well it fits, mark any differences on template.
4. Cutting the garboard planks
   1. Use the template to cut out two garboard planks from 1/32” lime, (this is ½” at scale size.) Leaving an allowance on the top edge for final fitting. The reason for this is that you are cutting these planks from a wide piece of timber and they tend to spring away from the center of the plank during cutting, thus altering from the template’s shape. (I use a scalpel freehand) Recheck using the template, remark if required; carefully plane the edges to match the pencil lines closely.
   2. Offer them up to the keel and check the shape. This is where extended ends to the mould fixing-battens come into use: loop large rubber-bands (Post Office type) down one side of the boat and over the end of the batten on the other side – thus holding the planks in place. You will need some packing timber to allow for the keel depth to ensure that the planks are held down well.
   3. In addition I use old clothes pegs, the type with the metal spring; the ends of these can be cut to do many jobs. In this case we need the tips to grip, so trim them back to give this clearance. Make any corrections to the fit of the planks; some beveling will be needed to achieve a close fit.
5. Attaching the garboard planks.
   1. I have got ahead of myself – you will need to apply wax or plastic tape to the edges of the moulds to avoid surplus glue preventing the hull’s removal!
   2. Once you are happy that all preparations are made mark a ‘sir-mark’ with pencil onto both plank and keel to show its correct position. Remove the plank and apply a neat pencil line 1/16” in from the top outside edge of the plank, using the batten clipped in place – this is the ‘land’ to take the next plank.
   3. Apply a neat bead of glue along the keel, stem and stern post; fit the plank to correspond with the sir-mark and clip it into place ensuring that the plank fits tightly against the keel, stem and stern post. Any surplus glue will ‘draw’ into the joint as it cures, provided it is not excessive. Leave to set; once set remove the clips and carry out the same procedure on the other side.
   4. You now have both garboards fitted forming the baseline for the remainder of the planking.
6. Planking-up the hull.
   

   Plank drawing

   1. Mark off the plank widths on each of the remaining moulds, from the garboard’s top edge, using the card method, remembering of course that the garboard is No1. Run the planking batten around the marks on the bilge to see if it looks a nice fair curve (no humps or bumps). If all OK extend the marks down the side of the mould by 1/4”; this makes the marks easy to see when fitting each plank.
   2. In this boat the planks will overlap by 1/16” so we need to fair off the top of the garboard for that amount until the lap-bevel lines up with the mould. Do this with a steel rule held against the top of the plank and resting on the mould. This will show how much timber needs to be shaved off the garboard, back to nothing at the 1/16” pencil line. In a model it might be possible to use glue to fill the gap rather than beveling (see Diagram A) I use a X-acto type chisel to gently remove this timber, followed by filing with a metal file to fair up the land.
   3. The new plank when laid in position will lie fully on the lap and touch the mould on the curve; at the stern it might be necessary to take off a shaving from the next plank to allow for the ‘tuck’ Gently form a tapered rebate at the garboard plank ends for a distance of ¼” to allow the next plank to bed in flush.
7. Plank Spiling.
   

   Plank rebate	Plank beveling	Spiling plank	Fore Ends

   1. Each plank has to be spiled-off to find the correct shape. In a clinker boat you cannot force the plank into shape edge wise, it has to be correct or the planks will start to lie off the moulds; in a carvel boat you can get away with some ‘edge set’ providing the plank is fair.This intermediate step is necessary to obtain the correct shape with minimum waste.
   2. To get the true shape of the next plank wrap a piece of scrap planking about ½” wide around the top of the garboard ensuring it overlaps all of it. By wrap I mean lay this spiling batten around without force so that it touches all the moulds as flat as possible, not lying off at all – use the rubber bands to hold it. I did try using clothes pegs as clamps as in full-size practice but found the template would not lie fair.
   3. Do not worry if the next plank marks do not line up at this stage. You will need to use a clothes peg at the bow, – we always used to nail a scrap piece of timber down the middle of the Apron to give the clamps or peg something to bite on.
      

      Fore Ends	Hull Half planked

      You can tell if the spiling plank is ok if it lies flat at the top edge of the lower plank and against the curve of the mould. If it lies off one or the other push the end slightly up or down until you achieve a good shape.  Then run a pencil around the template from inside marking the top of the garboard– you can now see why the moulds need to be up away from the baseboard if building up side down.
   4. Mark the stations and the ends on the inside if possible, allowing a bit over at the transom; mark the outside to show the stem shape and length, remove the template and turn it over – you will then see the shape of the next plank.
      

      Plank Shapes

   5. Lay this template on the lime sheet and clip it in position, mark off from the template marks using a pair of fine needle dividers, set wide enough to allow clearance over the edge of the spiling batten; add the station (stations are the moulds) and end marks.
   6. Remove template, clip the batten around the marks and run the pencil all along; this is now the bottom edge of the next plank. Using the dividers again, take-off the full width of plank at each station from the Land-line (not the edge) to the next planking mark on each mould in turn; transfer these to the plank, this gives you the top edge and full size of plank. Clip the batten around and check fair – this determines the good shape of the next plank.
8. Fitting the planks.
   

   Holding planking

   1. Cut out a pair of planks, freehand, with the scalpel leaving a little surplus and beware running below the line as the knife will try to and follow the grain; fair up the edges with the small plane.
   2. Offer up the spiled plank to its position, holding it with rubber bands etc and see how it fits; I found it helpful if fine pins are inserted at the land line into the moulds to act as guides when offering up the plank.
   3. Mark off the stem rebate line and cut to fit; carry out any minor adjustments if required and mark a sir-mark again to ensure fitting in correct position. Check that the ends fit snug into the rebate and come flush with the garboard ends. Take it off and mark in the land-line for the next plank. Cut in the rebate for the next plank at the ends.
   4. If all is well, fit and glue as before, do the other side to match using the same template, ensuring that when looking from the ends the top edge of the planks are matched for height – leave an allowance in case it needs more adjustment. Fix as before and then carry on in this way until the sheerline is reached.
      

   And there you have a fully planked hull!

9. Removing the hull.
   

   Removal	Timbered

   1. At this point, before removing the hull, the stem should be ‘bearded’ or beveled down to 1/16” at the front edge and off to nothing at the rebate or plank line, then fair-out to the full width of the keel at the forefoot (top of Drawing A). The stem and stern can now be unscrewed and the hull gently lifted off and turned over.
   2. A new base needs to be made with cradles cut to support the hull at about a quarter-in from each end, fix a block at the bow and stern to prevent end-ways movement; any necessary cleaning-up can now be carried out inside.
10. Lining a Counter stern.
    1. This in essence is how all boats are planked. In the case of a deep-heeled boat with a counter, the center is marked off in the same way to obtain No of planks.
    2. The batten is placed around the bilge to come up beneath the counter or tuck as it is called. The plank widths are now marked, as before working from the batten, those above will have an even reduction in shape back to the transom. Those below will get wider and wider as you proceed aft, there should be no need to use any stealers, you should get a lovely even line to the planking and the batten and marking should be adjusted until you arrive at this point. Only then can you start actually planking.
11. Diagonal/Carvel.
    

    Gig Planking

    1. In this combination type, which most Naval types, were built in. The moulds would be set up as before, either right way up or upside down which is easier in a model as the fit of the planks can be seen. A stringer would be fixed along above the sheerline, which of course is marked on the moulds and transferred as planking proceeds.
    2. Stringers need to be fitted spaced from keel to sheer, as this is what will give the boat her shape. First plank is laid at the center line sloping forward 45°
       from keel to gunwale; both edges must be shot straight. The end fitted to the keel and carefully wrapped around the boat so that it lies touching at all points.
    3. It is important that each plank is laid with the same tension, or you will find that when the second layer of planking is laid they will not lie flat.
    4. Glue the first plank in position, firstly at the hog finally sheer stringer otherwise you will be unable to remove hull on completion, ensure it is pressed flat to each stringer as you wrap it around the hull. Check it remains that way, if it is not slack the sheer clip or clamp and press the plank firmly down until you reach the sheer then finally tighten. Hopefully you have it right. This has to be done quickly as the glue I use has a 5’ slip time (Velo-set. Couldridge Industrial supplies.)
    5. Once cured, offer up the next plank, clipped as closely as possible without touching the previous plank, you can then scribe the shape onto the new plank, which will be a slight curve. Remove and shoot off to the line, refit to check fit. If ok glue and clamp as before, if you have got the tension right you will find the joint between lies flush. Amidships it is not too difficult but as you get towards the ends you will find the plank will need a slight twist to lie flat. Going forward the edge shape will be convex; going aft the shape will be concave.
    6. One thing I omitted to mention, transfer the sheer mark on each mould onto the planking as you reach each mould, otherwise you will have job to locate the sheer line once the outer planking is completed.
    7. Once you have completed the inner layer you can start on the outer, this can be either diagonal at right angles to the inner, or carvel plank dividing up as described before.
    8. Assuming carvel, work away from the keel. As you get towards the sheer you will find out if all your inner planking is at the same tension, if not it will show as buckling as you try and get the outer to fit snug. If you do find this is the case, all is not lost. Cut along the sheerline of the affected plank, and let it fly to its correct position. It will over lap the plank next to it, gently cut off this overlap which will be in the shape of a triangle, so the plank fits snugly.
    9. Carry on planking until complete, ensuring the top plank matches with the sheer line marks. Now you can remove the hull and turn over, sit in a set of supports to hold while internals completed. Now you can fit in any small pieces of plank inboard to make good if required.
       

       Gig

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