Things I've Learnt So Far...

The whole point of building the kayaks was to learn a little about the boat building process before tackling something bigger and more expensive. I've read extensively on other blogs, on boat designers web sites and in books borrowed from the library and from friends. Some of the snags I've encountered I've read about previously, because they seem to catch everybody out. I guess that means the first lesson is "There is no replacement for experience. Read all you like, but you don't know until you've done it."

So what are these common problems. The biggest surprise was handling the epoxy resin. It was also the area I had the most apprehension about. A common mistake, apparently is not mixing it thick enough when filleting or bonding. Now I've done that too. The epoxy by itself is about as viscous as maple syrup. It will run pretty much anywhere where its laid deep enough to not get soaked up by the wood grain. To make fillers it is mixed with small, low density spheres that bulk it up, thicken it and make it easier to sand. The spheres actually flow better than the resin, so it takes an awful lot of them to come up with a mix that defies gravity and stays where it is put. For bonding, the spheres are replaces by fibres that are so fine and short they look like dust. These thicken the mix more readily, but again I didn't use enough of them in the early stages. Its quite disheartening to watch that beautiful fillet that you've spent all the allotted 'wet' time shaping start slumping down the bilges into the bottom of the boat, just as the epoxy starts going off into its gel stage where it's no longer workable.

Tools I think I've got just about right. My two planes and my jigsaw get lot and lots of use. My cheap screwdrivers also seem to be getting a fair bit of use, usually while bonding up parts with epoxy, which now covers their handles, so its a good job they were cheap. I'm getting closer and closer to the dreaded sanding stage ready to paint the first boat. This may see some further tool expenditure in the form of an orbital sander. I have a very basic 1/3 sheet sander but it's so poor I usually find it quicker to put a 1/4 sheet round a cork block and use some elbow grease. Watch this space on the verdict of whether a power sander is worth its cost.

On timber, I think I got it right with the plywood, or if anything I maybe bought better than was required or the kayaks. That's by-the-by because anything bigger and of greater value would get the full-on BS1088 Marine Ply spec treatment, its silly to scrimp on the small difference in price per sheet between good ply and the best ply.

Where I got it wrong was with the finger-jointed softwood moulding I bought. Its OK for the inwales, they're really only there to provide a glue surface for the deck. The problem lies when I try to shape the stuff. Its very hard to plane a length of wood when the grain direction changes every 300-450mm. Because the grain changes direction and density, you can't use it to form a fair curve. It would be no good, for example, in forming a batten that was used to hag a plank off to derive the plank's shape. Again, I should have known this because I've read about other builders having trouble with finger-jointed softwood not curving well. Also, its not very strong. The same builders who can't get it to form a fair curve have also had it fail when bending over a tighter radius. I think I'll get some continuous lengths of 18mm square pine for the cockpit stringers before I put the deck on. After all, I've read the warnings from others and I know these parts are under stress when climbing in and out of the boat. It'll be one mistake I'm happy to learn from others making.

Running Strakes

I'm unsure as to what the correct name is for these parts, runners, strakes, false keel and bilge strakes, whatever. The point of them is to protect the thin-skinned kayak bottom from hidden nasties when launching and beaching. This is especially required since the beach most local to me is covered in oyster shells just below the high tide level.

The plans call for simple bevelling of the ends to provide a bit of streamlining and to please the eye a little more than a square-ended piece of wood. I went to town a bit while shaping the centre runner at the weekend, and had more fun with the two bilge runners.

To get them looking right, I only tapered their outer edges, leaving a straight line on the inner edge to run parallel to the longer centre runner. I paired up the pieces and planed them together to ensure good symmetry. Before stopping for dinner I managed to screw them temporarily in place, using a small offcut to get a constant distance from the centre piece. All the screws were placed from the inside, except on the aft ends of the bilge runners where the wood was too thin, so a round-headed screw and washer was used to hold down the end against the considerable curve of this part of the hull.

After dinner I went back to the garage and unscrewed the pieces to epoxy them on. The mix I used to fix the runners was a good thick microfibre blend. I glued and screwed each part back on to the boat before making some mixes of filler, part microfibre and part micro spheres, to fill any gaps between the edges of the runners and the hull. I also ran a tiny fillet against each edge to improve the look. By this time is was very dark, so sorry the photos are so glary, all were done by flash. I discovered, working at dusk in a lit garage, a benefit of the all-over Tyvek suit is it gives the mosquitoes very little bare skin to bite.

A Little More Progress

On Wednesday I got in a bit of time to tidy up and sand back the filling done on Monday. Some of the deeper filled areas had sunk where the super-absorbent end grain had sucked all of the epoxy out of the filler mix, lowering the fill level.

On Thursday I got in a good session and taped all the outer seams. I got the tapes good and tight with no wrinkles or kinks. I went easier on the wetting out on top of the tape and was confident of a cleaner end result.

On Friday I finished shovelling the earth and chopping down the old pergola posts.

On Saturday Bridgit helped me to clear the overgrown shrubs by the fence and we moved the trampoline into its new position.

On Sunday I cleaned up the outer side of the hull to get rid of the drips. Despite the care I took not to put excessive amounts of epoxy on the tapes on Thursday, there were lots of run lines on the side panels where the gradient is steepest. I cleaned these up with a bit of planing and lots of careful scraping with the tip of a very sharp chisel. I can see now why a cabinet scraper is such a useful tool to boat builders. I also used some 60 grit aluminium oxide paper to rough up the tapes ready to receive more epoxy.

Finally, I managed to shape the false keel that will act as a running strip to prevent wear on the thin panels of the hull. The plans suggest a simple taper cut on each end, but I went to town a bit with a fairly blunt fore end and a finely tapered aft end. I screwed this in place temporarily from the inside to use it as a centre marker. The next step will be to add another couple of rubbing strips on the bilges and the centre false keel will act as a datum to ensure everything is perfectly symmetrical.

And finally, some boat building

I got home on Monday evening and was determined to spend a few hours in the garage on the kayak. It was raining quite a lot, so that ruled out digging clay, but I had to wrap things up early to go to the Land Rover Club meeting.

There was just enough time to sand the outer joints and fill the gaps and any remaining stitch/screw holes with a micro fibre mix of epoxy. I'm getting more confident with the stuff and made a good thick mix which went almost entirely where I wanted it to, and hardly at all where I didn't.

I also had a good go at the twisted keel line at the stern with the block plane and got rid of most of the twist. After I've taped the seem I'll add a little more filler to one side than the other and no one will ever know...

Photos from the Weekend

This is a giant weta. Its a fairly common group of insects in New Zealand, and this one, the biggest live one I have seen, had a body about 60mm long with antennae about 3 times that. It was hiding in one of the joints of the old pergola I took down. I'll have to make a pile of old wood nearby to re-home it.


Here's the trampoline that has taken over the garden...


...And this small pile of clay is covering the last part of the old concrete patio that the trampoline will be moved to. On the left you can just see...


...The monster pile of clay retained by the old pergola timber. There's just enough room left to fit the small pile in with this lot. The frame on the upturned table has rusted out and it will be going to the tip shortly.

A Weekend in the Garden

We decided that it was time to do a bit of work on the garden. The new border that we created for the olive trees still wasn't finished, and we wanted to tidy the place up a bit before summer really gets going.

So on Saturday we went and loaded up the Land Rover with 180 litres of bark chippings and some more plants to finish thing off. I let Bridgit (a qualified seamstress) lay out the weed matting while I followed behind tucking it in to the edging strip. Once the last few plants were in and the bark was on, the whole lot looked much improved. So that's the view in one direction from the living room sorted.

In the other direction, we look out on to a huge trampoline that was gifted t me by a colleague. Sam loves it, and I have a quick bounce every now and again too. But its killing the grass and taking up too much space. We discussed the possibilities and decided that it would be great to move it over to a corner where an old rough concrete patio exits. Fine, apart from a spoil heap from a deck I built over a year ago currently fills the space.

I spent Sunday dismantling the very wonky pergola over the patio and recycling the wood into some temporary retaining. I then shovelled about 3 tonnes of soil and heavy clay from one side of the L-shaped concrete area to the other. I finished at about 7PM, totally exhausted but still with another tonne to move before the trampoline can be moved. And the weather doesn't look too clever for the next week, so it'll have to wait while I hide in the garage and get on with the kayak.

Photos to follow.

Another slow week

I've only managed to get dribs and drabs of time on the boat again this week. Mostly its been tidying up after the weekend. I had about 4 dozen screws to remove from the inwales, and various drips and runs to try and clean up.

On Thursday I got out of work a little earlier than usual, but decided to go and get more supplies on the way home. I went to the Glue Guru on Wairau Rd, Glenfield for some cheap brushes and some West Systems 410 low density filler to add to the epoxy. So far I've used 411 blended filler that is slightly more dense and therefore harder to sand. Since the main use for it now is as a fairing compound to smooth everything out, I think ease of sanding is very important.

I got home and planed a bit of the boat. To get more room I took it out of the garage and up to the deck. It was he first time in a while I've seen the outside lines, and it does look very sleek. I've noticed a slight curve to the centreline in the last foot or so, as the chine angle increases to make the stern almost fin like. I suspect this will impart a fair amount of natural curve to the boats travel, so I need to do something about it. The problem was a less than perfect alignment of the ply panels before they were joined. A combination of planing down one side and filling on the other might remedy the situation to a degree.

I think, on balance, I prefer the time I've spend shaping the wooden pieces to the time I've spent in a one piece Tyvek suit, gloves and goggles, smearing gloop over the pieces of wood in an attempt to stick them together. I've got a few ideas that will make building the sister boat, a two man version of the Dart, easier, less frustrating, and hopefully more refined. Some of the woodworking tools have become firm favourites, especially the block plane that is a delight to use. I'm thinking a ply lapstrake boat like the Rogue will require plenty of shaping so the wood to gloop, joy to misery ratio should be higher than with the kayak.

I had to stop early on the Thursday to have a kick about of the rugby ball with Sam. Besides, the clouds were gathering so I couldn't have stayed outside much longer anyway. While he was waiting for me to pack up and play with him, I got Sam to take this picture. Bridgit obviously feels left out and sought to remedy the situation by getting in on the act, but she may regret it when she realises that her pushed-up nose on the window is on the web for all to see.