Planking

Planking is eased considerably by the accuracy of the CNC cut planks supplied in the kit. We started out doing dry runs on the boat and drawing a tell tale with a rule across the scarfs, by the time we were halfway through the planking we were confident that using the kit scarf alignment method was accurate so didn’t bother with the dry run.

As usual, click on the thumbnail for the bigger picture

Mk1 Scarfing jig – later reworked to give a full width bearer at the front of the jig. The jig is built to give a 60mm scarf, equivalent to a 1:6.66 scarf angle.

Mk1 Scarfing jig, underside – showing longitudinal bearer for clamping in ‘workmate’

Planks labeled up before removing from the sheet, green and red used to differentiate port and stbd planks

Separating the planks from the ply sheet, a Japanese pull saw was ideal for this – Stanley knife or jigsaw are other ways of doing this

Mk 2 scarfing jig with first plank wedged in place, this one is 9″ between sides – slightly tight for the widest planks, 10″ would have been better.

First scarf cut – not too bad. The use of a new router bit helps get a clean finish

End view of scarfing jig, the free end of the plank is supported slightly higher than the jig baseplate to ensure some downward spring pressure to hold the knife edge of the scarf in place during routing.

The garboard planks glued up on the ‘scarfing bench’. For those that are interested the (unheated) shed temperature was about 5 deg C. We are confident that the glue will cure, it just might take a day longer

detail of the glued up scarf joint – note polythene release barrier between planks and clamps. It can be easy to forget this in the heat of the glueing operation!

A simple gauge to indicate the progress of the bevelling, devised by Topher to add certainty to the process. Out of interest the epoxy cured to sandable condition overnight at sub 5deg C.

First Garboard clamped in place for a trial fit. millimeter perfect for length which has us a little nervous. There is no room for error in scarfing these planks!

Stern apron, bevelling about halfway

Fine tuning the stern apron bevel, just a little to be removed from the hog around the apron joint.

Completed stern apron bevel, compare with the previous snap to see how the line has been faired in

Removing more of the hog to get the garbord to take its proper position

Final testing of bow apron bevel with gauge and scrap of planking stock.

Resultant scarf from the scarfing jig, not a lot of scope for improvement

Cutting the bevel at the gain on the first garboard, the next plank will have a matching bevel cut on the inside edge so that when fixed together the clinker overlap becomes flush at the stem

finishing the winding bevel with spokeshave, it is vital that the bevel is flat and not rounded on the faying surfaces

Richard wetting out the second garboard

Topher tweaking the lie of the first garboard and Richard wetting out the hog for the second

Wetting out the hog for the second garboard

First garboard glued in place

application of epoxy thickened with micro fibres

enough thickened epoxy to ensure a good squeeze out when garboard applied, this is a crusial joint so it is better to use too much rather than too little and have gaps that will need filling later. The surplus is easily removed with a suitable scraper whilst still wet.

Both Garboards glued in place, the screws are temporary until the glue has cured

Releasing screws gripped by the epoxy, about 75% of the temporary screws got well stuck in place. Rather than risk a snapped screw or mangled head application of a soldering iron for about 30 -60 seconds transfers enough heat to release the grip.

All temporary screws removed, use of a hand powered screwdriver gives much more control and ‘feel’ than a powered version.

The Ullapool Skiff Plank bearding gauge. Devised by Topher this is, we think, an elegant solution to beveling the aprons without the need to constantly lay on the planking stock. This should enable a precise fit of the outer stem over the planking.

Trying out plank 2 in a dry run, we found that plank 2 wouldn’t lie fair to its position on the moulds, some minor tweaking of the mould positions was needed to get a line we were happy with. Not sure why this happened.

Showing the discrepancy we had at the bow apron, the edge should have lined up with the pincil line beow it.

adjustment of moulds to get plank 2 to lie fair, this is mould 3, about 5mm being removed

adjusting the line of the plank edge, about 12mm was removed from the stern apron tapering to nothing around station 6

showing similar adjustment at the bow

the adjusted line at the stern

Dory lap for the gain at the bow

Plank 2 dry run after adjustment

Plank 2 dry run after adjustment

Plank 2 dry run after adjustment, bow detail

Plank 2 dry run after adjustment, bow detail

plank 2 glued in place, starboard bow

plank 2 glued in place, port bow

plank 2 glued in place, stern

plank 2 glued in place, broadside view

small void in half cut scarf on plank 3, not enough to worry about in this location, it almost vanished by the time the scarf was completed. If it had extended further we would have filled it with thickened epoxy when gluing up the scarf. Voids in the quality of ply used in these kits are extremely unusual, this is the first time I have seen one in 9mm ply.

Scarf damage, once cut the scarf is very vulnerable.

Just before gluing up the Port Plank 2 our lighting on that side blew so we clamped it up in deep shadow – this was the sad result.

Plank 2 in place

Marking the limit of the lap bevel with the lap gauge – our laps are now 22mm.

Dory lap at the stem between Garboard and plank 2

Glued up plank scarf before cleaning up

Grinding off the excess glue on the plank scarf

Grinding off the excess glue on the plank scarf face

Grinding off the excess glue on the plank scarf face, 2

Bearding bevel gauge in action

Our solution for the bump in the dark, we hope that a bit of brute force will persuade the plank to lie to a farer line.

Plank 3 glued and clamped

Broadside of first three planks

Clamping up plank 3 – all clamps (over 60) in use

To avoid the starved dog look we needed to support some sections of the planking between moulds

Detail of clamping for plank 3, stern portside with bumb adjuster

First three planks after clamp removal, plank 4 on scarfing bench in foreground.

Starb’d stern view after first 3 planks, we think a lovely sweep to the planking line as it meets the Apron

One of the consolations of working in a fridge is scenery like this, there is a dream(boat) at the end of this rainbow

Quality Control Manager using a high tech approach to rubbish disposal

clean up – done in stages reduces the apparent size of the job in the end

The team in harmony

Quality Control Managers stamp of ‘approval’

Plank 4 clamped and glued

Stbd plank 4, declamped and ready for beveling

Port plank 5 glued and clamped

beveled ready for plank 5

Aligning scarf on plank 6 – unusually the string line goes diagonally across the plank. If not we have got it horribly wrong ;-)

Aligning second scarf on plank 6 – again the string line goes diagonally across the plank

Plank 5 glued and clamped, view from bow

Plank 5 glued and clamped, view from stern

The stem beveling for the sheerstrake, note the shouldered end to avoid having an epoxy fill showing

Showing how the dory lap at the stem extends into the bevel for the next plank

dory lap with adjoining plank in place

pencil pointing out dory lap extension

slight bevel needed on top of stem end of the sheerstrake to fit the shoulder

Whisky plank in place – and no, we didn’t as it is a function of the quality control manager to appropriately mark the various stages – and he vanished at the crucial time

An array of dory lapped gains

Planked up hull from on high

Breadth of stem showing at garboard

And breadth of stem showing just below the sheerstrake. There is a reduction of about 1/4 inch over the apron due to the changing angle of the planks to the apron. This is not often realised and can lead to problems fitting the outer stem if forgotten.

And so we have finished this stage of our boat, next will be fitting the outer stems and keel. 

Things we have learned from this stage

• Make sure you know what the lap is, part of our problems with plank two was down to our assumption that the lap was 18mm – never presume to assume, it should have been a  minimum of 22mm and in places 25mm. We think we will be OK with our reduced lap – if not we will get very wet on launchday
• dont work in the dark – if you can’t see what you are working on properly it WILL go wrong.
• Our Epoxy works at a far lower temperature than the literature would have you believe, during planking we don’t think the temperature got above 5 deg C. and was often less. We are using West 105 resin/205RP (reduced phenols) hardener combination.

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