Shrike, a lightweight sea kayak for home construction.^

Places, technique, kayaks, safety, the sea...
ChrisJK
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progress

Post by ChrisJK »

An advantage of a self build is working at one's own pace.
The keyhole spray deck I have does seem to fit but needs replacing and once the work I have just done is cured and tidied upI will head to Go Kayaking with the cockpit to check out something to fit.
Once that's done it can go in.
First filletting
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Underside twilled and wetted.

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Topside twilled and wetted.

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To be trimmed and tidied.
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Re: Shrike, a lightweight sea kayak for home construction.^

Post by charleston14 »

Build video here, lovely looking result at the end, using veneer

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Re: Shrike, a lightweight sea kayak for home construction.^

Post by eskapist »

That's a very neat piece of boat building!
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Re: Shrike, a lightweight sea kayak for home construction.^

Post by nickcrowhurst »

Excellent work and video from Joe Yap in Singapore to produce a 3-piece Shrike. Well done, Joe!
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Two new Shrikes

Post by nickcrowhurst »

We now have a YouTube channel for Shrike videos. One of the videos we found was a surprise to us. One Nick H from Minnesota USA has built a Shrike, and, at the same time, built one for his girlfriend. That brings our total to 397 constructions. The video is followed by others from our YouTube channel:

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Not all Greenland-style kayaks are alike........

Post by nickcrowhurst »

For the next few minutes you’re an assistant in a store that sells quality woodworking tools. A customer walks in:

“I’d like to buy a good quality handsaw for cutting medium-sized timber. I’ve seen two I like on your display here. I’m leaning towards the one with the black shiny handle, but the one with the yellow handle looks good.”

“Well, the black one is a rip saw, and the yellow one is a crosscut. They are quite different saws. The rip saw is for cutting along the grain of the wood, and the cross-cut is for cutting across the grain. The rip saw teeth are all in the same line, but cross-cut teeth are set in alternate directions across the blade. Try looking down the blades and you’ll see the difference. Will you be mainly ripping or cross-cutting?

“Some of each.”

“You can buy a combination handsaw. It will rip and crosscut, but not as efficiently as either specialist saw. It’s the one with the green handle in the cabinet here.”

“No, thanks. I really like the look of the one with the shiny black handle. I’ll buy that one.”

I’ve had that sort of conversation a couple of times in connection with the decision about which sea kayak to build. Both times recently the gents have said:
“I can’t decide which kayak to build; a Shrike or a Brand X. I really like the look of the Brand X.”

“They are very different tools, although they are both based on Inuit kayaks for hunting seals. Greenland is a long narrow island running north-south. The west coast faces the prevailing strong winds and waves. West Greenland-style kayaks, (like Shrike and most of the well-known popular modern sea kayaks), must be able to chase and harpoon or shoot a seal in rough conditions while the seal is twisting and turning to escape. Hence they have a considerable keel rocker in the forward half of the hull and a vee-shaped hull so that they are manoeuverable and fast in rough water, dealing well with waves from abeam.
On the other hand, the east coast is generally sheltered from the strong westerly winds, and the water is frequently covered in patches of ice. The water is much smoother than on the west coast, but that means the hunter is more easily seen by the wary seals. What is required is a kayak that is fast to accelerate and very low in the water. Also, when within the hearing range of the seal, one must stop paddling and the kayak must carry on quietly in a straight line without further paddling until within killing range. We know that this is an unusual characteristic in a sea modern sea kayak, and this characteristic requires very little rocker and a flatter hull. For today’s kayaker these are “play and roll” kayaks.
Whichever you decide to build, you will have a kayak with a fine pedigree, but you must bear in mind that there are “horses for courses.”
………………………………………………………………
References: “Kayaks of Greenland” by Harvey Golden, pp 110 to 117. (The ultimate book on the subject)
east vs west: greenland kayak | Liquid Rhythm Journal (liquidrhythmkayaking.com)
choosingakayakforyourneeds (capefalconkayak.com)
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Re: Shrike, a lightweight sea kayak for home construction.^

Post by Oisin »

What kind of sales assistant are you? The customer clearly needed both kayaks, I mean saws, and probably didn't know he also needed a heap of clamps and a shiny block plane!

Sent from my FIG-LX1 using Tapatalk

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Re: Shrike, a lightweight sea kayak for home construction.^

Post by SteveKe »

I started this build between Christmas and New Year as something to do over the winter. I set up in a 20ft shipping container which I quickly discovered has zero insulation properties. Getting stuff to cure and dry was the biggest problem. Still, I am nearly there. The hull is painted in white marine paint and I'm about to varnish the deck. Things that went better than expected? - the maroski deck fittings turned out pretty well after a couple of practise attempts and the foam seat and footrests from Argyle and Kari-tek fit really well. Things I had trouble with? - the Kari-tek skeg kit was a pain in the backside and is almost too stiff to operate - not quite sure what i've done wrong but the biggest headache was right at the beginning when cutting the hull panels with the required accuracy...... I have to confess, I went back and bought a 4th sheet of marine ply to make a better job of it! I plan to launch next weekend on 6th Feb in Bude canal - fingers crossed. I also spent my time between waiting for epoxy, glue and paint to dry, making a wooden paddle and Norsaq. They are pretty crude but I tried them in my plastic sea kayak and they seem to work ok.
I'm not sure I have a build number yet? Maybe this one will make it a round 400?!


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Re: Shrike, a lightweight sea kayak for home construction.^

Post by nickcrowhurst »

Steve, it's a heroic effort to build inside a shipping container in the winter. Being cold is just miserable. A few points:
If a skeg system of any sort has been fitted correctly, but it is still stiff to operate, there's a technique which has never failed me:
Turn the hull upside down with the bow much lower than the stern. I rest the bow on a piece of carpet or wood or polythene on the ground, and the stern on a saw horse. Put some newspaper on the ground below the skeg hand slider.
Get the skeg fully activated (up in the air in this case) so that you can see the hole in the skeg box where the wire exits.
Get a spray can of silicon lubricant with a delivery tube that fits the nozzle, and spray down the hole where the wire disappears. Spray until fluid emerges from by the hand slider. Move the skeg back and forth a few times to distribute the lubricant.
Move the slider back and forth. Repeat the spraying and moving the hand slider until there is no more improvement or you get bored.
Reward yourself for a successful job with a couple of hot water bottles and a mug of something warming.
If the job is unsuccessful, it's perfectly acceptable to burst into tears.
For the next Shrike you build, cutting the hull panels accurately is safely done by cutting outside your pencil line by a few millimeters and then using a sharp plane to gradually finish to the line. (You may have been shivering too much to shape a nice curve.)
Your hull looks excellent, a triumph of persistence. I clocked you on the forum when you started the build, as Shrike 347. Together with Vember (a round-bilge Shrike), the total is now 397.
Great job, Steve!
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Re: Shrike, a lightweight sea kayak for home construction.^

Post by PlymouthDamo »

SteveKe wrote:
Fri Jan 28, 2022 1:16 pm
the Kari-tek skeg kit was a pain in the backside and is almost too stiff to operate - not quite sure what i've done wrong...
Other than lubing the wire, as per Nick's post, the other thing I discovered made my skeg glitchy was not having the plastic tube firmly secured in the boat and following as kink-free a path as possible. When I was converting one of my boats into a 3-piece, I had to move the skeg controller back to the day compartment and re-route the cable accordingly. I did a few trial operations of the skeg before I'd fully bonded everything in and found it was near-impossible to move. In the end it turned out that if the tube is free to squirm around, then that's what will happen rather than the wire passing cleanly through it. Once I'd bonded the tube in (by passing it through holes drilled in the deck beams and securing with epoxy) it went back to silky smooth operation.
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Re: Shrike, a lightweight sea kayak for home construction.^

Post by SteveKe »

Thanks all for your advice on the stiff skeg operation. It is now working smoothly!
I had a little launch party on Sunday to try it out for the first time on Bude sea canal (in 70kph winds). About 20 of my family and friends turned up to see whether it, (and me), could stay afloat. Happily it was a complete success and handled far better than I expected! Shrike 347 has been successfully launched thanks to CNC Kayaks and the copious advice I received through this forum.


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Re: Shrike, a lightweight sea kayak for home construction.^

Post by nickcrowhurst »

Steve, she looks very pretty. Good job, and many thanks for sharing the photo. You'll soon be in the Gallery.
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Two Swiss Shrikes

Post by nickcrowhurst »

Two identical Shrikes built in Switzerland 6 years ago, and I've only now discovered them at MacWester kayaks in Zurich, Switzerland:
https://www.facebook.com/macwester/

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We've hit the 400

Post by nickcrowhurst »

We know of 19 Shrikes in Australia, and this morning I received this email (surnames removed for privacy) from Paul, in Western Australia:

Hi Nick,
I have six more Shrikes you can add to your list, all in Western Australia.
1 John
2 Martin
3 Derek
4 Brian
5 Jo Folly,
6 Lindsay
Plus another two under construction, the Shrike is a great kayak, I own three boats and my Shrike gets used 80% of the time, I call it my all round boat.
I have also fitted a small skeg to my kayak and it has improved the downwind and surfing handling a lot.
I just think this boat is fantastic.

Cheers,
Paul.


We knew of most of these, but two are new constructions, and we await further details and photos. Meanwhile, that puts the total as 401. It's time to celebrate:
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Re: Shrike, a lightweight sea kayak for home construction.^

Post by nickcrowhurst »

Ajite in Minneapolis, USA, is sorting out the keel line, after Christopher happened to drop by:
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A fabric decked Shrike LV from Brazil

Post by nickcrowhurst »

Remarkable innovation from André in Brazil, with his fabric-decked Shrike LV. More details to follow:
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Re: Shrike, a lightweight sea kayak for home construction.^

Post by ChrisJK »

That's great and colourful using canvas on the deck had crossed my mind but I had the ply.
That is the enjoyment of the collaboration on working on materials and solutions with this ancient design that Nick has made accessible
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launching next week
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Re: Shrike, a lightweight sea kayak for home construction.^

Post by eskapist »

ChrisJK wrote: launching next week
Well done Chris! Despite your garage cum/workshop being less spacious than mine, you've beaten me to it!! And it's probably been a bit nippier in Cheshire than Norfolk lately? It took me ages to get the cockpit area of the ply bent to make a good transition from the masik curve to the flat aft deck while making good contact along the shearstrips. Soaking and steaming with a wall paper stripper eventually got a good result but it took days to dry out! As a result I only got the rear deck bonded on a couple of days ago and cleaned up this afternoon ready for glassing the hull over the coming week (I hope!), then I've still got the coaming to make up and install hatches, skeg gear and decklines, so it's looking more like April for mine.

Trevor
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Re: Shrike, a lightweight sea kayak for home construction.^

Post by ChrisJK »

Great thank you. It is in my house at the moment for a final cure while we are away. Plus bearing in mind my build was registered over a year ago and you have recently finished Vember that sounds good.progress.
Thank you to Nick, Damian, Daryl,Beryl,Chris plus yourself and overall contributors for advice and encouragement.
I’ll probably send an on the water picture and start a new Greenland paddle for a rest before I tackle a Vember
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Re: Shrike, a lightweight sea kayak for home construction.^

Post by Chris Bolton »

fabric-decked Shrike LV
That's very interesting. I'm hoping to built a minimum weight Shrike for my wife to use on inland water, and was wondering whether a fabric deck would reduce the weight. I wouldn't want one for a boat that would be used in waves, as I think the deck is an integral part of the longitudinal strength of the hull, but for flat water that shouldn't matter.
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Re: Shrike, a lightweight sea kayak for home construction.^

Post by darylf »

ChrisJK wrote:
Sat Feb 26, 2022 9:19 pm
launching next week
Great to see Chris! Your perseverance has paid off and produced a very tidy looking boat, look forward to seeing the launch day picture!
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Re: Shrike, a lightweight sea kayak for home construction.^

Post by eskapist »

Chris Bolton wrote:
Sun Feb 27, 2022 1:26 pm
fabric-decked Shrike LV
as I think the deck is an integral part of the longitudinal strength of the hull, but for flat water that shouldn't matter.
Hi Chris, if you use were to use heavyweight polyester fabric as per fabric covered aircraft and finish it using aviation products you would end up with a very strong structure. Maybe a little more cross bracing across and wider shearstrips to increase the glueing surface area wouldn't go amiss without adding much weight. There's 2 main brands of fabric, Dacron which is available from a company called Skycraft and Ceconite from Light Aero Spares.( Though this company only sells "certified" products which are more expensive than the " homebuilder's" supplies from Skycraft.
These fabrics are heat shrunk after gluing to the structure and can be made drum tight then waterproofed with butyrate dope. The result is very strong, watertight and puncture and UV resistant, repairs are easy too. The main downside is that you need a well ventilated workshop because of the vapours, but it is easy to do and a better results than canvas.

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Re: Shrike, a lightweight sea kayak for home construction.^

Post by mcgruff »

SteveKe wrote:
Mon Feb 07, 2022 10:11 am
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Wood deck and white hull is a beautiful finish :)
Have fun and don't die.
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Re: Shrike, a lightweight sea kayak for home construction.^

Post by Chris Bolton »

escapist wrote:Hi Chris, if you use were to use heavyweight polyester fabric as per fabric covered aircraft and finish it using aviation products you would end up with a very strong structure.
Hi Trevor, Thanks for that information, which will be very useful if I go down that road. My concern about the effect of a fabric deck in waves is not the local strength of the deck against wave impact or puncture, but the way the deck works in conjunction with the hull to resist longitudinal bending of the whole boat. In effect, the standard Shrike is a plywood box-beam. When supported towards the ends, on waves, the bottom of the hull is in tension and the deck in compression - but a fabric deck won't carry compression, so the boat has a channel section, which is much weaker than a full box. I hope that makes sense; I'm a structural engineer so it's easy for me to visualise. I've seen the effect in downriver racing boats, where the deck is often made lighter than the hull - and when the boat goes down a drop, the stern hits the ledge and the boat bends, causing compression buckling in the deck. The cracks are all overlapped a bit, and the side seam is usually debonded at the cracks, showing that it's longitudinal compression that's caused them. It's one reason (of several) why open canoes need quite substantial gunwales.
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Re: Shrike, a lightweight sea kayak for home construction.^

Post by eskapist »

Hmm, I totally understand your concern about the" open box" and longitudinal compression of the boat, though if the intended use is flat water only maybe the failure load point wouldn't be reached. Fuselage structure SOF boats using polyester skins seem to survive quite well, though it's true to say that many of them only use laced structures and not bonded ones. Would a full depth vertical web running the length of the boat (apart from the cockpit !!!) reduce the risk of any compression failure? Though in the end additional structure will only add weight and complexity, and as mcgruff succinctly shows in his photo above, a ply deck does look good, and as regards weight, my almost completed LV should be 12kg which is quite light despite my use of 4mm instead of 3mm ply for the two bottom panels.
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It's been a while/ Thanks

Post by ChrisJK »

Thanks Nick for the design and all those who have helped me on the way.
I had a lovely 12k paddle with Colin and Keith heading upstream/downstream Sandy lane to Crook of Dee Sandy lane. Falling out only when trying the legs out while moving forward to land exit.
Loved the boat , it was solid,stable and tracked straight despite my fisty build.

We had some challenges with wind over current and boat wakes.

It was a breeze to get on and off my car, one doesn't necessarily comprehend a photo of some one with a kayak on their shoulders but this is lighter than my 8 ft WW boat.

From my boat builders view there were some snags including a sudden bloom of amine blush and some minor leaks but I'll work on them,

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Thanks to Colin for the photos
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Re: Shrike, a lightweight sea kayak for home construction.^

Post by seawolf856 »

It was a privilege to be invited by ChrisJK to the launch of his Shrike No275 on the river Dee in Chester on Saturday and I'm delighted that I could provide Chris with photographic evidence of just how good his Shrike looks on the water.
Chris' passion and dedication to this build is inspirational and it was great to see his inaugural voyage was a success. The boat looked fantastic on the water and despite some blustery conditions easily kept pace with us.
Thanks again for the invite to witness such a rare event. Good luck with the finishing touches and I hope to see you out on the sea in Shrike 275 some day.
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Re: It's been a while/ Thanks

Post by nickcrowhurst »

ChrisJK wrote:
Sat Mar 05, 2022 9:10 pm
From my boat builders view there were some snags including a sudden bloom of amine blush and some minor leaks but I'll work on them,
Well done Chris, for overcoming the problems of winter cold weather working. Regarding the amine blush, I would paint the kayak. My prototype had a variety of "uglies" that a pot of black paint from B&Q soon sorted.
Leaks are easily traced on dry land by using a garden hose to fill the three compartments, in turn, with water to just beyond the level of the outside sea or river when afloat. The most common leak is from the skeg box corners , as described at page 61 of the Build Manual:

How do I make sure my Skeg box does not leak?
Two builders have reported water leaks from the top corners of the standard plywood skeg box. The plywood and inner solid wood framing of the box have simple joints at these points, so there is potential for leaks. We recommend special care to ensure the skeg box is water-tight. Do not use excessive clamping pressure which would exclude all epoxy adhesive from the joints. Apply glass fibre tape and resin over the outside perimeter of the box. Spoon a small amount of warm thin resin into the upside down box while it is on the bench, before the hole is drilled for the skeg wire fitting, and tip the box so as to run the resin into the joints. Leave the box upside down until the resin is set. Taking extra care at this stage is less trouble than attempting to cure such a leak after the kayak has been completed and launched. Filling the box with water is a good test.


The only leak that I've had trouble tracing was one that I isolated to the stern compartment. I eliminated the skeg box by testing, but the very slow leak continued. With the compartment part filled by hose, I eventually spotted about six tiny drops of water in a straight line, oozing from the outside of the topsides. The holes through the 3 mm ply could only have a tiny fraction of a millimetre in diameter. They were so small that they had broken through the surface tension of coats of epoxy resin and paint. I forced epoxy resin into the holes, and painted. The leak was sealed.
I inspected my other unused plywood, and found similar piercings, perhaps two on each sheet. My only unsubstantiated and uneducated guess is that in the factory, the sheets are moved about by mechanical claws with very fine probes.
Nick.
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Re: Shrike, a lightweight sea kayak for home construction.^

Post by ChrisJK »

Thanks Nick
I have learnt a lot about things I’d never have considered!
The amine blush was not too extensive and I removed the worst of it after the paddle with detergent and a washing up scour pad and the sharp end of a wooden scrubbing brush.

I had had a helpful chat with Phil at Fyne boat kits he reminded me that epoxy curing is non linear and a full cure takes 7 days at 25 degrees at 18 it might be double that and at 10 that could be three weeks so I’ve definitely been pushing the envelope.

I did comment to Seawolf that “paint covers a multitude of sins”
At present I can live with the “uglies” as the wood looks so good plus on the water it moves so fast no one is going to have time to study. Off the water it is an object lesson.

I did have some leaks from the upper deck I have perhaps idiosyncratically plugged where I think they are with some cheese wax from an Edam cheese (I am half Dutch)
The other possible point is round the skeg joint along the hull as my skeg is a kayak sport with flanges.

I think if anyone is thinking of building “In plain air” and an unheated place then in the UK ideally every thing would be just about joined, cut out and either formed and stitched ready to fillet tape etc unless you’ve got a few weeks to spend rather than limited time. Had I not had to self isolate for a few days just recently I’d not be this far ahead.
Basically having started in April or May I was ready to coat between September and now with a large gap between October and February. Impatience to get it on the water was getting the better of me.

Thanks again for this lovely design and project
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Re: Shrike, a lightweight sea kayak for home construction.^

Post by nickcrowhurst »

We've emailed our best wishes to Viktor in Ukraine:
https://cnckayaks.com/2021/10/18/bitkop-from-ukraine/

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