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Stitch and Glue Laker

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Skin on Frame Curlew

Comparison of 3 kayak construction methods.


There is a considerable amount of information on home building kayaks in the Wiki already so this is specifically about my experience building kayaks by 3 different methods – stitch and glue (S&G), cedar strip and skin on frame (SOF). Note that none of the designs I built are SOT.
There are other build methods such as lapstrake and fibreglass but this write up is just about the 3 I have tried.
Also included are comments about local factors, particularly available materials, and a variation on the S&G technique.

I found that there are pros and cons for each method both in terms of the building process and in the final product.
The comparison table summarises the differences and similarities of each aspect but I have also developed a personal preference for a construction type based on my own views and needs and also influenced by what is most readily available in terms of materials.
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Cedar Strip - Own design

In the comparison table I have described ease of build using only ratings of  "Easy" or "Not hard". This is because each individual part of the process is not difficult even though the entire build may be lengthy.

As far as cost goes I don’t think there is a lot of difference – they are all going to be well under $1000 so are good value for a custom boat.
Weight wise I’ve found some difference but not much. Stitch and glue will tend to be slightly heavier than the others but the final weight really comes down to a number of factors including intended use, builder experience and available materials. My kayaks range from about 14.5kg to 15.5kg.
The important difference is in the practical side but appearance can be a factor for some people.


While any method can produ
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Deck of strip built kayak

ce a capable boat for all sorts of conditions there is one particular disadvantage of the SOF that I would prefer not to put up with and that is the inability to install bulkheads. Of course this is technically incorrect as you could install a bulkhead of sorts - but it would need to be flexible or it would put a ridge in the hull that would increase drag and create a wear area. It would be very difficult to make a flexible one strong enough to hold back the water after a wet exit and it would also somehow have to seal around the frame stringers. So from the practical viewpoint it is necessary to use float bags if you want to safely go any reasonable distance from the shoreline.

Float bags are able to reduce the amount of water in the hull in the event of a capsize but there is always the need to pull them out to dry the hull after use to prevent  rot/mould, then reinstall them for the next outing. Mine cost $75 and these were in the budget range of what is readily available. Some people are happy with this but I prefer the bulkhead option.

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Interior of SOF showing float bag and footpegs

Other advantages of bulkheads apart from buoyancy are that they provide dry storage and it is easy to open a hatch to ensure dryness between trips. So for me this boils my preference down to a choice between stitch and glue or timber strip.

Stitch and glue can make some good hulls and there are a number of designers offering multichine design plans and kits. If you want to design your own there is software available but I believe it is more difficult to learn than the one I used for the strip build. I have not used any of the other programs but from discussions on other forums I have this impression. There is also the question of materials and I seem to have developed a mild aversion to plywood. This is due to a combination of the difficulty in obtaining good ply at a reasonable price in this country, the tendency for splintery edges, the apparent waste and the need to handle large panels in the initial stages.
Still, if you want a good solid hull with minimal work this is the way to go.

A relatively recent development in S&G is known as SS&G, short for strip, stitch and glue. This involves using timber strips glued together to make panels which are then used as ply would be for a S&G design. In Australia we are blessed with plantation grown paulownia which is even lighter than western red cedar with similar strength and if I ever do another S&G design this will be what I use. From what I have seen it looks like it would be cheaper than using high quality marine ply too. I’m hoping someone out there will do a Jem Sabalo in paulownia one day as I reckon it would be an amazingly light fishing SOT if the right timber thickness and glass weight were used.

Overall my preference is for cedar strip. From an appearance viewpoint they can be the best for both the shape and the timber colour/patterns but this really is a personal thing and a good paint job can be impressive on any type of hull. Any advantage of strip building comes at a cost of greater labour – 2 or 3 times the duration of the other methods - but some of us like that kind of thing and I much prefer working with solid timber than with ply. A combination of colour contrasting paulownia and western red cedar can be used to make some simple but impressive patterns and this can be further enhanced by small amounts of denser timbers for other contrasts. Of course this can also be done in SS&G.

I believe that a slightly lighter hull is achievable with strip building and it enables creation of true compound curves, giving slightly better rigidity and potentially a more efficient hull. The software also enables a high degree of customisation with good predictions for drag and stability. The software I used for the strip build is called Kayak Foundry and is easy to start using. I really enjoyed the design stage but be careful if you try it because as you progress you will find that there is much more to kayak design than learning the software.

For those that do not want to design their own there are good plans available for all types. Kits are also out there for S&G and SOF but I am not sure about strip building.

Each build has been a positive and educational experience and resulted in a good kayak, although they are all good at different things, and I’m looking forward to some more strip builds – when I get my shed back.

Apart from construction method my kayaks are also all very different in design. Here is a brief comparison of the designs.
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Laker 13’ long by 26” beam – good for flat water fishing, photography and light touring. Open cockpit design makes fishing easy. A good amount of usable cargo volume for a smallish kayak. Will handle a bit of chop but not recommended for the sea.





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Curlew 15’ long by 24” beam – good for faster cruising, light fishing, photography. Not a lot of usable cargo volume or cockpit space. For fishing take minimal gear and be prepared for
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little catch storage space.






Cedar strip own design 11’ long by 24” beam – very stable - good for inshore fishing and photography and will handle rough conditions. Too short for covering long distances. Small cockpit opening to allow use of spraydeck going through surf zone. Again, minimal fishing gear and a couple of reasonable size snapper would occupy most of the catch storage space.







Comparison TableEdit

Stitch and glue Wood Strip

SOF - ply frame

Ease of build          Easy Not hard  Not hard
Build time    Medium (50 - 100 hours)    Long (200+ hours)    Short (40 - 80 Hours?)
Appearance           OK Good

OK

Designs   .    Hard chine Rounded   Hard chine
Designing own          Need software for panels - can be 2 stage Kayak Foundry (free - but good) Need software for panels - can be 2 stage
Ruggedness         Tough enough Tough enough OK - more risk of puncture.
Flotation       Built in bulkheads Built in bulkheads    Float bags needed
Storage    Dry compartments with bulkheads    Dry compartments with bulkheads    Drybags needed
Weight    OK with light glass and good ply. Possibly better with SSG.   Good (esp with Paulownia and light glass)    Good - with light timber type and skin weight
Normal Maintenance    Varnish at 3 - 5 years. Patch wear spots as required   Varnish at 3 - 5 years. Patch wear spots as required    Patch and paint as required. Reskin at ~10 years?
Repair   Easy, but appearance may be affected.    Easy, but appearance may be affected.    Doable but likely not as easy as others.
Main materials  

Ply
Glass cloth
Epoxy
Fillers (can use sawdust/wood flour)
Varnish   

Timber strips or boards

Glass cloth
Epoxy
Fillers (can use sawdust/wood flour)
Varnish   

Timber - stringers

Ply - frames
Skin fabric (eg polyester or nylon)
Sealing coating (eg Paint)
Thread
Sinew
Oil (eg Tung, teak or linseed)

Processes         Marking out and cutting wood
Shaping (plane, rasp, abrasives)
Drilling
Gluing and filling
Fibreglassing
Varnishing
Sanding
 Marking out and cutting wood
Shaping (plane, rasp, abrasives)
Drilling
Gluing and filling
Fibreglassing
Varnishing
Sanding

Marking out and cutting wood and fabric
Planing, rasping, sanding
Gluing
Lashing
Drilling
Painting and oiling
Sewing

Cost    All typically in $400 to $800 range - depends on location, material quality, brands, work input etc      

Plans can be bought for all 3 styles and there is software available for own designs as well.

General

Skin damage, broken frame, broken stringer are all repairable but likely to be not as easy as others. Extreme frame / stringer damage may need reskinning.

MaterialsEdit

PlywoodEdit

Quality    Beware of internal voids.
Face plies to be at least 1mm thick - thin ones will sand through. Waterproof glue not necessary if both side glassed.
N/A    Beware of internal voids. Face ply thickness is not so important as the ply is only used internally . Must have waterproof glue.
Availability   Can get marine ply to BS1088 or AS2722 but it is very expensive in Aus. Look for something with properties based on quality notes above.       N/A As for S&G
Comments    Beware of fake BS1088 - (thin face plies.)      N/A  As for S&G
Alternatives   Can make panels from wood strips instead of ply. This can be lighter and looks better. Technique is known as strip, stitch and glue (SSG)    N/A    Bent rib designs are available. These take more work but may be better for some people.

TimberEdit

Quality    Not so important - little used.    Straight grained best. Grain run out increases risk of broken strips Straight grained best. Grain run out increases risk of broken stringers.
Availability     OK  Paulownia and WRC available – shipping from eastern states is a factor. Good quality Paulownia available in Aust from NQld and Vic at reasonable prices.    Paulownia and WRC available - shipping from eastern states is a factor
Comments     Light is good but not used in quantity so not too important  Can use wavy/curly grained strips for some areas but for sheer strips and tight curves they may break. Paulownia / WRC give good contrast for patterned decks.   
Alternatives    Can use any ply but may not be as good   Can use others but they will add weight – not recommended.    Can use others but they will add weight - not recommended.

Fibreglass clothEdit

Quality   Watch quality. Cheap ebay stuff may be stiff and not suited to use with epoxy despite them saying it is OK. I had to strip a hull and do it again because of this.  As for S&G N/A
Availability     OK, lighter weights are harder to find and more expensive.       As for S&G N/A
Comments   Use lightest that will suit use of kayak. If it is looked after then 2.5oz is fine. For rough stuff like around rock gardens etc 6oz or even possibly more BUT weight will suffer.        As for S&G N/A
Alternatives   Others types such as carbon fibre, kevlar etc are expensive and not necessarily better – not recommended.        As for S&G N/A

EpoxyEdit

Quality     Use marine grade only  Use marine grade only    N/A
Availability        OK OK   
Comments    Main brands for Aus: WEST, Bote Cote, FGI R180 . I used R180 - most people stick with the first one they use as they have learnt how to use it As for S&G Only used in small quantities as a glue if at all. See notes for other methods
Alternatives           Polyester used by some but is full of solvents, not as adhesive, not as strong, doesn't give clear finish with glass etc - my advice is don't go there

Skin fabricEdit

Quality         N/A N/A  Needs to give smooth finish when painted.
Availability           N/A N/A Skins - from USA is easiest - no direct suppliers known of in Aus
Comments         N/A  N/A Nylon more puncture resistant but needs care to stop wrinkling and takes less variety of finishes. PVC needs glue
Alternatives          N/A  N/A Nylon, polyester, PVC

FinishEdit

Quality        UV resistant clear or paint.  UV resistant clear or paint. Want abrasion resistant, waterproof and smooth.
Availability       OK OK    OK for paint. Coatings for nylon may need to be imported.
Comments         Some people paint hull, clear finish deck.  As for S&G Can decorate as 2 tone, logos, patterns etc
Alternatives           Single pack urethane is reasonable cost, easy application and long lasting, 2 pack urethane tougher (?). As for S&G Oil based enamel is good on polyester. Could use 2 pack or other urethanes.

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