Freedom Kayaks Ltd

Introduction

This document is prepared to assist with the building of one of Yakayak’s designs. It is not meant to be a comprehensive document that has to be followed prescriptively, but more a guide to assist the home builder avoid some of the pitfalls that we have probably already made at Freedom Kayaks Ltd and point out some of the tips that we have discovered along the way.

As with all things there are numerous ways to achieve a task and we are not suggesting that you cannot do it your own way or in a way that you prefer and works for you. We are also not going to increase the cost of our products by providing things such as ‘home build videos’ as these are already comprehensively available from the internet or in books from reputable kayak builders at none or little cost.

Building your kayak is not difficult, it will take time and the finish of the kayak will depend on your attention to detail, however anyone can build a light and strong, useable kayak from Yakayak designs. At any point if you do have that bewildered feeling, Freedom Kayaks Ltd is always happy to offer guidance and if we don’t know the answer than we know where to find out. No special tools are required for the build and most items can be bought easily and cheaply. Freedom Kayaks Ltd does have a preference for keeping things simple and trying to avoid excessive waste, so lots of the items listed can be reused. However with epoxy and paints/varnish there are inevitably items that will be one use.

In addition to this guide there is a library of Build photos and associated explanation on Freedom Kayaks Ltd website for you to check as your build progresses. We would also welcome any comments or additions you feel necessary to this build guide.

Equipment/Techniques

Building from Offsets – If you are building from ‘offsets’, mark up the plywood boards with the graduation all the way across the board, for example Fulmar is 10cm graduations. The two figures for each graduation can then be marked using a panel pin. This allows a bendy edge to be held up against the pins and marked for a ‘fair’ curve. This will give you the required panel. Each panel usually needs two so the first can be used as a template for the second and then the two planed and sanded together to ensure they are identical.

10cm graduations Panel pins at measurement 1 and 2

If you have a bought a kit, you will be building using CNC Cut panels. These are extremely accurate and you will find that they fit together with ease.

Joining panels – This can be done different ways. One is butt jointing where the panels are butted together and then fibreglass and epoxy used across the joints to join them. They need to be fibre glassed on both sides. The other common way is ‘scarf’ joints where the ends of the panels are wedge shaped and then glued with epoxy together. If you have bought a kit then you can join the ‘fingers’ of the join by placing the panels to be joined on a plastic surface, put the panels nearly together and spread the epoxy glue mix into the joint. Then push together completely. Clean excess of this joint and ensure flat. This joint can then be sanded tidy after epoxy has set.

Butt jointScarf Joint

Panel

Fibreglass/epoxy

Epoxy mixtures – There are a wide range of epoxy fillers for a wide variety of uses. It is possible to use plain sawdust which provides a very strong mixture, but I find harder to work with for filleting than a purpose made ‘filleting blend’. I then use the filleting blend for gluing, filling and filleting duties to keep the colour and consistency of the mixture consistent (once you get used to using one type of filler it is easier to make batch after batch with the correct consistency. The same goes for epoxy). I use plain sawdust in large fill areas that are unseen. Epoxy mixture for gluing needs to be glue consistency. Epoxy for Filling needs to be just thick enough then when you scoop some out with the stirrer it does not sag, if it sags on the stirrer in the pot then it will sag on the kayak.

The only other additive to epoxy I use I make up from the off cuts of fibreglass cloth which I chop up into small 5-10mm lengths and add to epoxy. I use this to fill any hole or problems when the fibreglass is laid onto the kayak. This mixture makes very hard but clear filler.

Baby spoons are used for stirring the mixture and for filleting. They are cheap and reusable.

Plastic drinking cups are cheap and good to use for most epoxy duties. Note that some polyurethane paints will dissolve the cup before your eyes and rapid set epoxy mixtures in a good ambient temperature will reduce then to a melted mess. In these circumstances I have baby food containers.

Plastic scraper for general use.

Cheap masking tape can be used for filleting, however put it into the kayak fillet and remove. Do not leave on kayak as can become hard to get off or pull up grain on plywood. Under no circumstances use cheap masking tape for painting duties, it is useless and paint will go under it – use paint block masking tape.

Cheap sandpaper is false economy. You will spend so much time sanding the kayak you may as well have a good sandpaper to make the job that bit easier.

Materials

3 X 4mm Marine Plywood 2440mm X 1220mm Sheets or CNC kit

7.5Kg Epoxy

10.40m 25mm X 25mm planed pine

7m X 1m 135g/m2 fibre glass cloth

20m of 75mm width Fibre glass tape

Epoxy filleting blend

Foot braces

Seat

Varnish/paint as required

Plastic spoons and cups

Sandpaper

Kit contents

Hull

X12 Total - Consists of 3 pairs for the bow and 3 matching pairs for the stern. Positions shown on plan.

X4 Total – Consists of 2 pairs, that join into the middle of upper two chine panels either side of hull.

Cockpit

X6 semi circle cock pit spacers, with X2 semi circle cockpit rims for cockpit top

Bulk heads

X4 – 2 for bow and 2 for stern. NOTE: depending onhatch requirements may not need bow or stern most bulk head.

Deck and miscellaneous

X2 700mm X 2400mm Marine Plywood panels – The front and rear decks are cut out from these.

Also the spare not used for decks is used in the join for decks and foot brace mounts.

Build

Please note there is a build gallery Freedom Kayaks Ltd website that may assist if you cannot visualise any of the steps below

Forming the Hull

  1. Join panels either with the ‘finger joins’ if a kit Scarf join. If scarf joining the panels will need to be cut longer to allow for the scarf joint overlap. This requires a large flat area to ensure the panels are flat and aligned properly. After they have been joined ensure that they are sanded and joints are tidy.
  2. The hull can now be formed on a bench or workhorses. I start with the bottom and drill holes in both panels along the bottom line putting in cheap garden wire for ‘stitches’. The stitches need to be loose to start with and I do not put in every stitch to start, but miss out some putting in every 4th stitch or so. I do this for every panel until the hull is roughly formed. I then have a scrap of wood to the length of 59cm which I put across the top of the middle of the kayak. This keeps it ‘open’ and also gives the desired measurement.
  3. I then use a piece of 120 grade sandpaper folded around a scrap piece of 4mm plywood to sand the edges of the joints between panels. If you hold the sandpaper vertical between the joints you easily produce the correct bevel doing both edges at the same time. You will have to remove then replace the stitches as you reach them. They do not need to be perfect, but the edges just need the square taken off so that they stop sliding against each other.
  1. After all joints have been lightly sanded then all stitches can be put in, but again the stitches are still not done up tightly. Some areas need more than others due to the bend being put on the plywood.
  2. The hull can now be trued. Firstly I check for ‘flat’ spots where the hull is sat on the workhorses. This can be cured by moving workhorses closer of further apart, by adding another prop underneath the middle of the hull or bow and stern. You should not be able to move the hull to much without the top edges flaring out or squeezing in. If you can the stitches are too loose so tweak them tighter.
  3. Next I use two uprights off each workhorse and put a piece of wood across these with a level. Take your time with this and step 5. The bow and stern tips will not at this time pull together nicely with the stitches but the next step will cure that. Be careful with the uprights not to make a ‘flat’ spot in the hull deck line. The uprights should just touch the deck line of the hull. Their shape will come later with the shearclamp.
  4. Once you are happy with the shape, use pliers to tighten the stitches throughout the hull. Correct any gaps or tight spots. I use two pieces of wood either side of the bow and stern then G clamps to pull the panels together nicely. Do not tighten the G clamps too much or it can pull the bow and stern out of shape making it concave.
  5. You can now use a tiny amount of glue epoxy mixture to ‘dot by each stitch. When this is dry it allows you to remove the stitch. Be sure not to make these dots bigger than the fillet is going to be or you will have sanding to do.
  6. Once the dots of epoxy are dry the stitches can be removed with sharp wire cutters.
  7. I add bulk heads at this stage. How many bulk heads are a matter for preference, but I always add two if there are going to be no deck hatches and four if there are deck hatches. This ensures that there is always a sealed of buoyancy area even if a hatch fails. On bulk heads I like to put in inspection hatches to allow inspection and ventilation when the kayak is not in use.

Bulk head positions – Showing the 4 bulk heads.

330cm

180cm

Bow Stern

50cm90cm

Filleting the Hull

  1. Now the joints can be filleted including the bulk head joins with the hull. This process can be done all in one or split into two with a small amount of sanding but a very tidy finish. I start with the cockpit section and fillet all the joints using epoxy mix with WEST SYSTEMS 405 filleting blend. There are other things you can use but I like the texture of this when filleting. I then leave this to dry and sand the fillets, these are the fillets that will be seen by everyone so is worth taking time to make them good. You can use cheap masking tape either side of the fillet when applying the fillet mixture and then remove it immediately after finishing filleting to help ensure a clean finish.
  2. After the cockpit fillets have been sanded, fibreglass cloth is laid in the cockpit and wetted out with epoxy. This will need to be left to dry and probably repeated 3-4 times to completely wet out the fabric.
  3. In the mean time the bow and stern section fillets can be done. This can be done in the same way as the cockpit section, but as there is less abrasion likely hood, I fillet the joints and immediately tape them when semi set with Fibreglass tapewhich is again immediately wetted out with the first coat of epoxy. Again this tape will need about 3 more coats with drying time between.
  4. BEST PRACTICE – regarding wetting out the fibreglass cloth, it is best practice to wet the cloth or tape, leave to dry then recoat when dry or after 1 day. If layers are built up like this it allows the layers to chemical bond to each other. If a period of time is left between applications of layers there will be no chemical bond and the layers in time could cause problems. If nothing can be done to apply layer after layer, wash the coat off to ensure there is no ‘amine blush’ a waxy coating some epoxies can get, then abrade with sandpaper and carry on with the next coat.

Shear Clamps and deck beams

  1. Shearclamps will need to be scarfed together to ensure they are long enough to fit the entire length of the hull inside. To form the scarf joint the shearclamps can be stacked on top of each other with the length of the scarf protruding out from each one. The sander (belt sander) can then be held at this angle and easily produces the required scarf:

Belt sander angle

  1. Notches will need to be cut at the top of the bulk heads to allow the shearclamps to be fitted. If the shearclamps are proving too hard to bend this can be assisted by steaming the shearclam or making slight vertical notches a few mm’s deep with a saw in the inside edge of the shearclamp at intervals. Do not go too deep and these cuts will need filling carefully after the shearclamp is fitted. The shearclamp does not want to be flush with the top of the deck as it will need shaping to accept the curve of the deck. At the bow and stern of the kayak the curve is less so less needs to be protruding than at the middle where the curve is greatest.

Deck curve

Shearclamp

Hull inside

  1. Once happy the bend can be achieved and the shearclamp is the right length with the ends trimmed at an angle so they fit together. The shearclamps can be glued in place using and epoxy glue mix and then held with lots and lots of clamps.
  2. Whilst the shearclamps are being fitted, the deck beams can be made. If I am using 4 bulk heads I only use 2 beams and if I am using only 2 bulk heads I use four beams. Therefore it is obvious when using 4 deck beams the front and stern most beams go in the position of the bow and stern most bulk heads as they are not being used. The middle two deck beams that are always used are position so the the cockpit coaming will be glued onto the deck above them. This allows them to take the strain front and rear of the weight put on the cockpit coaming as people enter and exit the kayak.
  3. Two make the deck beams I cut a jig from OSB board to the radius required for bow and stern deck, note they are different radius so 2 jigs will be rquired. Holes are then cut to take the G clamps to bend the ply laminates into place while they are glued together:

Ply laminates clamped down over jig

Jig – Bow deck radius 32cm / Stern deck radius 70cm

  1. When gluing the laminates together and pulling down over jig with clamps please note this is very messy with epoxy glue mix getting everywhere. Ensure the jig is on plastic and that the top of the jig has parcel tape stuck over it or you will not get your deck beam off as it will glue to the jig. If you are making 2 bow and 2 stern deck beams, if the jig is wide enough you can make one wide deck beam and then cut it in two after gluing to give you your two deck beams quickly and easily.
  2. Once the deck beams have been made these can be used to shape the top of the shearclamps by sanding to the desired curve. Place the deck beam on the top and work you way down the kayak a bit at a time. Work the two side shearclamps together a bit at a time as sanding the one side will affect the angle of the deck beam on the other. This is another stage that is worth really taking your time as if done slowly and thoroughly will provide a good and clean join between the deck and hull. The top of the bulk heads may need shaping slightly to ensure that they also smoothly follow the contour of the deck.
  3. After this shaping of the shearclamps the deck beams can be glued into their positions. If not using 4 bulk heads the bow and stern most deck beams can be glued into positions where the bow and stern most bulk head would have gone in the diagram under step 10. The cockpit deck beams – Front 240cm from tip of bow / Rear 200cm from tip of stern.
  4. The outside of the hull can now be filled with epoxy fillet mixture between the joints of panels. Also the ‘stitch’ holes are filled at the same time. Please take time to ensure these small stitch holes are filled properly and do not just remain a hollow void with filler over the top as when you sand it flush there will be a tip hole that will cause you problems when fibre glassing the hull – They cause bubbles in the fibreglass.

Fit out inside of hull