Back to work

It’s Spring, and doesn’t that make everything easier!

I got fed up with the $10 dining table, so built a proper work bench. Why didn’t I do that ages ago. So I’m back to cutting and scarfing the planks again. But now I am actually enjoying it, and it is *so* much easier doing it in little pieces, rather than trying to scarf two full size sheets together.

So with any luck, I’ll soon finish making the planks, and finally start stitching them together.

I am really missing having a well-written, prescriptive book like ‘The Strip-Built Sea Kayak‘ that I had for the Guillemot. There are lots of books about boat-building, but none I have found as comprehensive and suitable for a novice as Nick’s.

Scarfing plywood sheets

The Stornoway 12′ requires planks longer than a standard 4′ x 8′ sheet of plywood. So the idea is to join two pieces.

Scarfing (or ‘scarphing’) is the process of joining two pieces of wood using a long wedge-cut on each piece, to create a large glue surface area. The idea is to create a joint as strong as the wood itself, and, when bending the timber, that bends the same as the wood. To achieve this, a wedge that is 6-8 times longer than the thickness of the timber is recommended.

The plans imply that it’s a good idea to scarf the sheets before cutting planks. Seems simple enough. Just trim a wedge off the end of each sheet with an electric plane, epoxy each end, and compress the join on a flat surface.

If only it was that simple.

I have found some evidence of builders who have done this successfully, but I am not one of them!

Long story short:
- this requires a very large, very flat and very stable surface (which my $10 old dining table does not offer) to place the sheet on when planing the wedge, and when compressing the join while the epoxy sets. I tried using two sheets of 12″ MDF as a surface on the table and even so my wedges were still not planing consistently.
- a tiny inconsistency in wedge cross-section means you will have a) a weak join and b) most likely, a ‘step’ up from one sheet to the next.
- stacking several sheets, offset 50mm back each time, to plane them all at once seems a good idea, but is basically impossible with an electric plane.

After two attempts I’ve given up. With a decent workbench or flat floor it would probably be fine but I don’t have either of those luxuries. The joins I did do came out ok-ish, but I can tell they are weak in some areas. I cut one set of planks from a joined sheet, but I am concerned that for some there is a slight step either side of the join, from one sheet to the next, which would be very difficult to sand out (so would create an ‘unfair’ surface on the hull).

We have also decided on a 25mm scarf rather than 50mm. This is shorter than recommended but we are going to sheath the hull inside and out with 6oz glass fibre cloth, so that will make up for any weakness. And Dad reckons that’s what they used for the GP14′s he and Grandpa built (with no glass reinforcement) so that’ll do me.

So I have decided instead to cut the planks in two pieces from separate sheets, and scarf them together individually. It should be a lot easier to trim a wedge shape from piece no more than 25cm or so across than a sheet 1220 across. I hope!

I have used the full length planks which I’d already cut as templates for the second set, and once they have been cut and joined I’ll chop the short section off each of the first set and scarf new ends on.

I’m looking forward to moving on from this and stitching the planks together.

Strongback

Stitching planks together apparently doesn’t require the use of a strongback, because simply stitching the panels together means the panels bend to form the shape of the hull.

But we might modify the interior, and build tanks into the sides for bouyancy and to provide a seat at deck level. Having a strongback will help to build the tank walls for fitting inside the hull.

Also I can’t really see how you can be sure that the boat will adopt the planned shape (let alone symmetrical) without some sort of strongback to check it. So I built one anyway.

I’m missing having a book as prescriptive as Nick Schade’s The Strip-Built Sea Kayak as used for the Guillemot. I’m glad Dad has built dinghies like this before to have someone to call on.

Strip plank or stitch and glue?

I was originally planning to strip plank the Stornoway, partly because I am familiar with it now having strip planked the kayak, but mostly because for some reason I thought marine ply was super expensive. Well, it’s not. At NZD65/sheet for 6mm ply it works out cheaper to plank the hull with ply than to buy cedar and mill strips.

So we have decided to stitch and glue instead, which is what the plans were originally drawn for. So today I bought six sheets of 6mm marine ply, and a 4m plank of 50x150mm Malaysian Kauri. We will rip this into mostly 25×25 strips, and use it as the framing and runners. I agree with Dad, that the kauri (a pale yellow) will nicely complement the ply (quite dark brown). Later I will buy some oregon to use for the spars.

Thanks again to the guys at Timspec, for having a great selection and friendly staff.

All the wood required for the Stornoway

Lofting the Stornoway

We’ve had an exciting time here in Christchurch, what with the earthquake in late February and all that … but we are amongst the lucky ones with not too much impact on our livelihoods and our home. So I was very happy to receive the plans in the post a few days after the earthquake struck (thanks NZ Post!), and they have been a welcome distraction!

The plans are beautifully hand drawn and very informative:

Dad and I enjoyed a couple of hours poring over these working out what order to tackle things in.

I’ve bought some cheap sheets of 12mm MDF and framing timber to make up the strongback, which is the next job.

Stornoway 12′

I’m very excited. We had a great summer holiday with Pip (Guillemot Kayak), and messing around in some borrowed rowing dinghies. So Dad and I are going to build a 12′ sailing dinghy.

I ordered the plans today – we are going to build a Stornoway 12′, designed by Paul Fisher of Selway Fisher designs. Paul maintains a Yahoo group for builders here.

The idea is to build enough to have a rowing shell this year, and rig the boat next year … we’ll see how we get on!

Guillemot Kayak blog home

This page is the home page for my blog articles about the Guillemot Kayak. You can use the ‘Guillemot kayak’ menu above to follow the build. These two articles seem to get the most search results:

Milling Strips details milling ¼” x ¾” strips, and cutting the cove and bead on the edges.

Strongback covers building the internal strongback, especially to line the forms up accurately.

The Guillemot wood strip kayak

December 2008: a few months ago I came across Nick Schade’s website about his wooden kayaks, built with thin strips of wood and glass fibre.

After watching one of Nick’s kayak trip videos along the Maine coast I decided I’ve got to build one of these.

I’ve never really been kayaking, but I’ve always wanted to build a boat (my Dad used to sail and build his own). And New Zealand has some fantastic kayaking spots, including around Nelson where we often holiday.

Nick’s book was in our local library. I read it through while my copy was on order. It’s well written and an essential resource. I’m going to build the Guillemot.

Ross Leidy’s kayak building website is also a great source of ideas, including a full diary of building a Guillemot, and also Vaclav Stejskal from One Ocean Kayaks.

So this blog is to track the progress. I reckon it’ll take about a year – let’s see what happens (it’s now 28 December 2008). [Edit: I finally launched Pip exactly two years later.]

Launch party!

First paddle!

Beautiful weather in a bay just before Charteris Bay, in Lyttelton Harbour. A wonderful way to spend Christmas Eve, with family and friends.

Pip is named after my dad’s mother, who is the first of three generations of Johnson wives who have put up with boats being built in their houses (my grandfather built two in their lounge, including bolting the frame to the floor). My thanks and appreciation to Mum and Dad for the use of their garage for the last year, Dad for his advice and counsel especially in the recent final stages, and special thanks to my wife Sarah who has supported the project and my time to complete it.

Happy Christmas

Sarah dribbling some Petrie bubbly for the launch.

Dad relives launching his own home-built kayak, err, a fair number of years ago

Back on the rack ... and back into the workshop to add the finishing touches (bulkheads, remainder of rigging, handles, seat and footpegs)

Fixing the hull glass

When I glassed the hull exterior, I did something silly, which was to lay 3″ glass tape along the keel *under* the full layer of glass. Result: an ugly line and ridge along each side of the keel.

I also decided at the time not to add a second layer of glass on the flat of the hull.

Having joined the halves, and sanded the exterior reasonably smooth, I decided to sand out the ridge. This meant sanding through the top layer of glass, so today I added a layer of glass over the flat of the hull and along the keel line at the stems.

This will give me a smooth surface and more abrasion resistance along the hull.

An extra layer on the flat section of the hull, the football

I saw a trick in one of Nick’s videos. It involves masking off the desired area, then trimming the glass to overlap the masking tape just a bit. Then about 12 hours after putting the glass on, while it is still pliable, lifting the tape and running a razor blade along, to smooth the transition at the edge of the glass. It was quite effective … I’ll still need to sand it a bit, but will hopefully be ready for varnish in about a week.

Joining the hull and deck. Finally!

It was very exciting to finally be doing this task, after nearly two years working on the project. Once the deck and hull are joined, it’s definitely the home stretch.

First I had to tape the seams closed. Book binding tape was ideal.

Aligning the seam, and taping it

Ready for taping the inside seam

I’ve read lots of notes on this process. The basic idea is the same – unroll a predetermined length of 2″ fibreglass tape, already soaked in resin, along each seam on the inside, wait for it to set, the tape the seam on the outside.

A little helper

Vaclav’s building guide suggests piping some filler in before unrolling the glass. I think this is broadly aimed at builds where the angle at which the deck and hull meets is not essentially flat. But in my own case, I had over-bevelled the sheerline strips, so although it made for a nice tidy edge on the outside, there was a V gap between them on the inside. Not much – only about a millimetre (roughly 3/64″) or so. But I was concerned that the gap needed filling before the tape was rolled on top, otherwise the resin from the tape would all sink into the gap and starve the tape itself of resin.

Now the bow and stern are roughly 5′ to 6′ from each hatch. So … how to pipe some filler into the ends, and ideally only along the seam, and only enough to fill it.

Vaclav suggests using a cauking gun. I don’t have one. But I did have a 10ml plastic syringe and some 1/4″ gardening hose (the black stuff for watering systems). The hose fitted neatly onto the syringe. It worked better than expected – the hose was mounted on a 3′ piece of doweling. The end of the hose ran nicely along the seam, and I squeezed the syringe. I can’t quite believe how well it worked – it made it very easy to ensure that the seam was filled right up to the ends.

The syringe pumps filler along a 1/4" flexible hose, right along the seam

It is a very tight squeeze getting your head and arm in with a respirator and head torch on. (Now I know why the dimensions in Nick’s book are for such large hatches.)

No nukes

A tight squeeze fitting in the hatch. Now I know why Nick's book includes such large hatch dimensions.

Next was rolling the tape on top. This too was easier than expected. The glass tap I have has a cotton thread along one edge, which as I discovered meant the tape didn’t stretch. It did stretch a little along the other edge, so running the thread side on the inside of the curve made it quite easy to push it right to the end. I’d read that you can’t really expect to get into the last 6″, but in fact this was quite easy (maybe this design lends itself to that more than others).

One side filled and taped

The notes I read suggested using a brush mounted on a stick to push and massage the roll along. But I found it easier to just use a piece of scrap strip to push it, and then an old film cannister pot stuck on the stick was ideal for running along the tape to push out bubbles and generally push it down.