There are several methods that can be used to build your own kayak. Build your own can be a cheaper (and nicer) alternative to buying one of the many fibreglass or plastic kayaks on the market. This wiki page has been written to describe some of the processes required to get out on the water and fishing in your own ‘yak’.
There are many DIY designs to choose from. You can also even design one yourself and build it successfully, but extreme care needs to be taken in producing a seaworthy design. Best option though is to visit one of the many websites and buy off the shelf plans. All good sets of plans should include as a minimum several drawings giving all dimensions, a materials list and a full instruction manual on how to do everything needed to build your dream.
If you can’t find what you want “off the shelf” most good designers, for a fee, will design a custom kayak to fit your exact requirements. Many builders have gone down this route and now own a one off design that is far superior to anything that can be bought in a shop.
For the ocean going kayak fisher a long and relatively narrow kayak should be looked for. A raised bow will help cut through waves and chop on the surface of the water. A long, narrow kayak should cut through the water easily and cruise along nicely to your favourite reef or drop off. An estuary angler can look for something a little shorter and slightly wider as paddling distance is likely to be shorter in all but the largest estuary systems. A river or lake angler can go with a short kayak as waves are less of a problem.
The same principles apply to kayak choice for the DIYer as they do for someone looking to buy from a kayak shop. Always ask around as to what is suitable for your needs and always make an informed decision. A lot of questions asked before buying (that may sound stupid to some) can make the difference between an average kayak and a great kayak. Just remember that a one off DIY kayak can be just as good as something bought in a shop.
Plywood – Generally the best plywood for a kayak is going to be the lightest and strongest available. Marine ply to British Standard BS1088 should be used wherever possible, although there are US and Australian standards also. Some use exterior grade ply or even ply from their local large DIY chain. Care must always be taken in ply selection. Voids, large loose knots of wood and poor gluing of the plies in plywood are very bad for the DIY kayaker. Always make sure that you inspect the plywood and if you are not happy about something, there’s always another timber merchant to go to. Okume is generally regarded as the strongest, lightest and most rot resistant of all types of marine ply and if available in your area it is always worth the premium cost. Hoop pine is also another common marine ply around the world and is extremely popular. There are many to choose from, but choose wisely for the longest lasting kayak (or boat for that matter).
Timber – Strip plank built kayaks can be built from almost any timber, but a rot resistant timber is best. The rewards for a strip built kayak are an extremely eye pleasing kayak provided it is done correctly. Many hardwoods are suitable and can be intermixed to provide some great and unique designs. Some kayak designs call for log chines. This is where a 12 x 12 mm (or other similar dimensions) long length of timber is screwed or nailed onto plywood and offers quick “bolt together” construction as there is no waiting for glue to dry. Knot free, straight grained timber is always the best for this as it bends and conforms to the kayaks curved shape very easily. Timber may also be used for creating bulkheads or stiffeners and really has a multitude of uses.
Epoxy – There a many different epoxy glues on the market now specifically designed for boat construction. West System, Epiglass HT9000, Botecote, Raka, MAS and System Three are to name only a handful of the many available. Every builder is different and uses a different epoxy. Most however use one of the brands above as these are all tried and tested over many years. Epoxy can be modified to different mixes for different purposes, a glue powder can be added for extra strength, sawdust can be added to colour match the timber, there’s silica, graphite powder, microballons, phenolic spheres and others to make particular brews of epoxies for sheathing, coating, gluing, filling and fairing. Each mix has its own purpose. Straight epoxy can also be used in the laminating of fibreglass cloth in with sheathed timber or pure fibreglass kayaks.
Polyester Resin – This is cheaper but no where near as strong as epoxy resin. Some DIYer’s swear by it and only use this resin, but the majority will only ever use epoxy. Polyester resin use must be very well ventilated work shops to avoid the unpleasant and toxic fumes.
Sheathing Cloth – There are several choices here for coating plywood or constructing a full fibreglass or carbon fibre hull. The most common cloths are fibreglass, dynel, Kevlar and carbon fibre. Each to their own, but fibreglass cloth is by far the most popular although the others are gaining popularity for the additional abrasion resistance they provide. All of the cloths need to be glued with either epoxy or polyester resin systems.
Foam – This can be used as inbuilt floatation, or even to do something similar to a surfboard or surf ski. Gluing foam blocks together and carving out a kayak shape can easily be done. One problem with foam is the weight. Kayaks are often light weight structures for the DIYer. Foam should always be closed cell to prevent water logging. There is little information around on this construction method so hopefully someone can add more here.
Construction Methods Edit
Stitch and Glue – This has become the most popular method for kayak building for the DIY builder. The method is based on a very simple concept of using the skin of the hull to transfer all of the loads put onto the kayak. It is very strong when done correctly. It involves cutting out plywood shapes and stitching them together with wire or cable ties. Epoxy glue is then applied to the joints between the plywood panels. The epoxy, when set in around 24 hours, is then strong enough to allow removal of the wires or cable ties. A rounded epoxy fillet is then applied to fully join the plywood panels. The whole of the inside and outside of the hull can be sheathed in fibreglass cloth and epoxy resin but this is not necessary and fibreglass tape and epoxy is used only on the joints in the plywood. The design requirements must be checked for the designer’s requirements.
Bead & coved strips..using timber with the ability to make complex curves. Epoxied over.
Fibreglass – This involves either buying or making a mold to lay fibreglass over and then coating with either epoxy or polyester resin. More Later........Flump
The list can be very few. A stitch and glue kayak can be built using a minimum of a hand saw to cut the plywood, a drill for stitch holes, pliers for the stitching, flat bladed screwdriver for a few adjustments to the stitches, with scissors/sharp knife and throw away paint brushes for the epoxying, along with heaps of sandpaper, pretty simple and basic!
Generally though power tools rule. A jigsaw with a fine toothed blade makes cutting the plywood easier. A hand or electric plane for trimming panels helps. A random orbital sander with sanding disks makes sanding less of a pain. A dremel style tool helps with sanding and grinding getting into nooks and crannies. A cordless drill (with a corded drill for when the cordless battery is flat and you need to drill two more holes!) for drilling stitch holes and fitment holes. A router for trimming bits and bobs and rounding edges.
Other hand tools that are useful include a carbide scraper for removing lumps of epoxy quickly, chisels, files, craft knives, hacksaws, clamps and the list just goes on.
Start small with power tools, get a jigsaw, a cordless drill and a random orbital sander, these couple of tools can be bought cheaply and save a huge amount of time.
Work Area Edit
For your work area you wil need around 1 metre all the way round the kayak to be able to move freely and easily. You can do it with less but it becomes awkward climbing over freshly painted epoxy.
Try to keep your workplace pretty clean and as dust free as possible. Use the dust catchers on the power tools to try and help minimise dust. Dust kills paint and epoxy jobs on all boats so keeping this to a minimum really helps get that special finish on your kayak.
Bought plans should be written in plain and understandable language. Diagrams, photos, sketches and text are generally pretty easy to understand and clear. Most designers now have web based forums and technical support with a large following of very knowledgable builders on the website that can help you through your kayak building experience. It's unlikely that any problem you have with any element of your build hasn't been experienced by someone somewhere and pretty much everyone is willing to help if asked politely.
Launch Day Edit
http://i24.photobucket.com/albums/c32/hairymick/Southern%20Cross/South%20Wind%20Fishing/IMG_0586Small.jpg Hairymick's launch day with Southwind
http://www.akff.net/forum/download.php?id=3747&type=image.jpg Flump's launch day with Thala