Shrike, a lightweight sea kayak for home construction.^

[ChrisJK]

Adventureagent The minimum space needed Is something like 18ft by say 4ft preferably covered but I have managed with a mixture of inside and outside construction with the boat at present living diagonally resting on a trailer holding a ride on mower and another smaller trailer in front of that. Time is of course necessary along with tenacity, I actually started building around April II should finish by the spring. Support from other contributors has been invaluable.
Thank you for the project

[simonballantine]

Here are a couple of photos of my newly-completed 3-piece Shrike. This one has been built for maximum strength with 200g/m2 carbon twill sheathing throughout, with a double carbon layer beneath the cockpit. All the inner surfaces are sheathed in 100g/m2 glass with a double layer in the cockpit. So it is essentially a composite boat with a plywood core.
Further strength features include a series of ribs within the cockpit, which increase rigidity considerably; plus partial bulkheads towards the ends where I do not need any storage; plus a collision bulkhead with a 4" hatch within the bow and stern compartments.
I have rounded-off the gunwale quite a lot so that the carbon cloth drapes over the deck and hull in one piece, jointing at the keel.
This all weighs in at 17Kg, which I am quite happy with. Nearly 2Kg of this is the 3-piece bolting system, which is also made super-strong. The boat feels very strong and more rigid than many GRP boats..

[nickcrowhurst]

Simon, brilliant work! How did you manage to cover the hull and deck with the joint at the keel? Did you suspend the kayak from points within the cockpit? I've done that to resin coat the entire kayak, but never imagined one could use cloth in the same manner, with gravity doing its worst to unpeel it.

[Oisin]

That's some result Simon well done! I feel sorry for any rocks you clip in that boat, costal erosion!

[simonballantine]

How did you manage to cover the hull and deck with the joint at the keel?

The 1m wide fabric did not reach wholly down to the keel in the central section, where it was supported on two trestles quite close together under the cockpit area. I weighed down the cockpit with bricks to stop it tipping when you pushed down on the bow and stern. The boat lay on its chine and I rocked it from one side to the other as I laid up the fabric down the sides of the hull.
The bottom plank was only half-covered, since the fabric was only a meter wide. I subsequently turned the boat over, tapered the edges and and filled these areas in with offcuts. I then added a second full layer to the bottom plank for extra strength and to give a uniform surface.

[simonballantine]

Laying up the carbon to the bottom plank upside-down worked fine. I pre-wetted the plywood so that it had some grab. It was a horribly messy job however and my garage floor is now resin-coated!

[nickcrowhurst]

I can just imagine myself riding a wave ....... Just unspeakably marvellous.

adventureagent has it right. What joy!:



The free plans download now includes a new version of the Shrike Manual. It includes a few points that you have requested, e.g "Try standing on the foot bulkhead paper plan in your paddling shoes with your feet splayed, to check if you need to change the height of the bulkhead curve or the topsides."
The Builders' Tips appendix now included full details of Simon's 3-piece Shrike construction, and ChrisJK's ocean cockpit rim technique.

There is also, for the first time, a French language translation of the Shrike Build Manual in the plans download. I only know of three Shrikes and Vembers in France, whereas, for example, the are 25 in Russia. The French Manual is a step towards improving that situation.
Our grateful thanks go to Francoise Cooper, a native French speaker who lives in England, for all her excellent work on the translation.

Downloads for the two new manuals are here: https://cnckayaks.com/shrike/downloads/
It's been a busy week, with six new constructions starting:

Mike in the USA - A Vembex to go with his wife's Vember.
Max in Moscow starting a Vembex
Martin in Austria, an astonishingly skilled metal engraver, starting a Vember.
Michelle in Singapore a Shrike-R once she's tracked down suitable plywood.
and Atilla in Hungary has completed two Shrikes:

[nickcrowhurst]

Brian Gilbert, in Australia, paddles his Shrike with his own brand of Greenland paddle https://www.seablade.com.au/about

[nickcrowhurst]

Kurt has opted for an ocean cockpit and reduced height of topsides in his Shrike. He writes (from somewhere in the Alps, I suspect):
I’m enclosing some pix of the Shrike Too I built last winter. I love my Shrike Too! Its ocean cockpit gives me the snug fit I like, and it paddles like a dream; I only have to think about edging and the kayak carves a beautful arc in the water. On days when I’ve had it out in a strong wind I’ve not noticed much tendency to weathercock either; its low deck and responsiveness to edging make it track like an arrow in flight. And it has such beautiful, clean lines. Thanks for sharing such a great design!

[nickcrowhurst]

Bobby has started a 35% scale Shrike in balsa wood, covered in glass. This is a grand winter project. More photos to follow when the model is completed.

[nickcrowhurst]

From Dave:
Here’s a photo of my Shrike-R. I finished it earlier this year as a dedicated rolling machine. I built it at 92% to match my weight, as suggested in the build sizing chart. I trimmed the very ends a bit, too, so the boat came in at 14’7”. It’s a squeeze to get into it, but as I hoped it rolls like a dream. I even pulled off a hand roll, something I hadn’t done before. Total weight is 29 pounds, so it’s a pleasure to put it on the car for a quick trip to the lake.

[nickcrowhurst]

Roel from Belgium:
"I downloaded the plans in April, and I started the build of a 100% shrike in the beginning of September.
It's the first kayak I've ever build.
The shrike was finished by the end of October.
It weighs in at 22 kg, but it's coated with 160gr twill inside and outside.
This project was my first experience with epoxy, but I'm pretty satisfied with the result. Maybe the result could be a little lighter if my epoxycoats would have been thinner.
I used PETG maroske fittings, and used a clear finish to showcase the nice Okoume grain of the plywood.
I installed a Kajaksport skeg system to save some time during the build.

Due to the bad weather since the kayak was finished, I only took it out once until now.
It handles really nice, great speed and manoeuvrability.

Thank you very much for the plans.
I already printed the plans at 90%, to build another shrike for my wife.
That way I can correct my rookie mistakes, to make a perfect one."

[nickcrowhurst]

Andrey in Russia has built a 2-section Shrike;
"Thanks for the plan. Made your kayak from two parts. I did not have time to paint, it got colder, the snow was promised (And I really wanted to ride)."

[wrp7317]

I have built RC aircraft in the past and decided to use some of my spare balsa wood for the build. The kayak is 3’ long and was fun to build. I used the Shrike plans as a template and cut everything out of 1/8” and 1/16” balsa wood. After assembly I used a light weight fiberglass cloth and West System resin. I even carved a Greenland paddle for it out of basswood. The kayak is currently in the paint shop, a cardboard box, and will be finished soon. I’ll post pictures of it when I’m done.

[nickcrowhurst]

Lucius in Romania has built a Vember and a Shrike:
"I am one of those who built the two kayaks. There are not enough words to thank you for your generosity and altruism. The first was normal Vember. Then a normal Shrike. Both are wonderful: Vember, very stable and tolerant of a beginner, but fast and easy to drive; Shrike also very fast and manoeuvrable.
I respectfully wish you a long life and happy holidays!"

[wrp7317]

Just came out of the paint booth. Next are the deck lines. I even made a Redfish seat for it.

[nickcrowhurst]

There's a builder in the USA who wishes to transport his plywood pieces for a full-size Shrike home by using his car. Some big stores have a superb almost vertical panel machine where your sheet material can be cut horizontally for 1$ after the first free cut. (Home Depot, B&Q)This saves tedious marking out and sawing the first two sheets that form the Shrike hull. He wishes to saw the third plywood sheet for the decks, so that he can transport them in his car. One thin sheet would not be advisable on a roof-rack. In the Build Manual we recommend making patterns with newspaper. The sheet has to be cut at an angle as shown in the picture. I've done my best to supply the accurate route of the required saw cut, but it's easy to screw up if you don't use paper patterns. Don't ask us how we know....
Do anyone of you builders still have the paper patterns, or are soon to make this cut? If so, I'd be grateful for a verdict on whether my drawing works for a full-size Shrike. I'd hate to be the cause of a screw-up. An accurate drawing could also be a useful addition to the Builders' Tips appendix.
Nick.

[wrp7317]

Deck lines installed. I used a 1.2 mm bungee cord I found on Amazon. Wanted to go for a paddle, but Santa beat me to it. Merry Christmas and a Happy New Year.

[nickcrowhurst]

Deck lines installed.

What cunning method did you use to secure the small loop on the foredeck?
It would be much appreciated if you could help the project by taking a 35% scale paper pattern of a full plywood sheet of 1220 mm x 2440 mm, (427 x 854) and overlay paper patterns of your model's foredeck, (length 2440 when full-size), and the stern deck, (length 2440 when full-size), to check if my estimated cut line of the sheet would work for a 100% Shrike. The foredeck finishes on the masik, just ahead of the cockpit. The stern deck has to have a small triangle fitted at the stern during actual construction to make up the required length, but you should ignore that. We usually allow a 20mm (7 mm at scale) overlap at the gunwales for trimming (and screw-ups!). The prototype Shrike has a plywood width of 630 mm at the masik, so I allow 670 mm at the junction of the decks on the masik. That would be the maximum. I hate to think of some unfortunate builder making the wrong cut because of my incompetence. If you can confirm it works, I can put your contribution into the Builders' Tips Appendix to the Build manual.(Perhaps with a photo?) Please PM me with any queries via the "contact" tab to the right of each post. Many thanks,
Nick.

[SteveKe]

Hi all.
It’s decision time! I have everything assembled for a shrike build which I’m going to start over Christmas. I have two sets of plans - one at 100% scale and one scaled up to 102.5%.
I initially thought I would scale up given my weight of 200lbs coupled with the fact I have only ever really paddled plastic “recreational” sea kayaks where stability isn’t an issue.
Then I considered my usage and concluded that the most I would paddle it is on day trips and really won’t carry much stuff. Probably the majority of my paddles will be a few hours along the coast around Bude in Cornwall, so I ordered plans at 100% scale.
Which should I build? Am I being paranoid in thinking I need the bigger size for better stability. Will it actually make much difference at all? BTW - I have read this entire thread at least twice - what a fantastic resource! You are all so generous with your advice. Thx. S.

[nickcrowhurst]

Steve, from the graph at page 57 of the Build Manual you will be fine at 100%. I suggest that when she is completed you take her for a few paddles on flat water to get used to the feel of a West Greenland-inspired sea kayak. How about Roadford Lake, 20 miles inland from Bude? It's £8 for a day, which goes against the grain, but it might be a good investment.
We're delighted that you are joining us all.
Best wishes, from Nick.

[SteveKe]

Thanks Nick. I figured I was just being a bit over cautious. There is also a simpler solution - instead of sizing the Shrike up, I could size my body down! That should be all the post-Christmas motivation I need to shed a few pounds. If i am after a bit of a flat water bash in Bude I have the mile long sea-canal to paddle up and down right on my doorstep (literally). It gets a little tedious but good to practice technique. I'll let you know how I get on.
Thanks again
Steve

[nickcrowhurst]

Lei from Yale, Connecticut, USA, built this very pretty Shrike LV for his 14 year old son. That was two years ago, and his 16 year old now wants a full size Shrike. Excellent!

[eskapist]

Nick, regarding your request for confirmation of your estimate of the panel sizing and in the absence of someone draping some paper over their completed Shrike ( c'mon guys there's a lot of them about!) I will lay some paper over my part built 90% version in the morning for you to cross check your calculation.
I had intended to start this build on new year's day but I got itchy hands looking at all my unused materials laying about my workshop and the rate that it's going with all the " workshop weather" that we're having out here in the East of England. There's no picture's of the build to post because there's nothing different about it, except that I have used 4mm ply for the bottom sheet because I had it in stock and and I'm not bothered about a slight weight increase and I only have 2 sheets of 3mm anyway. One other minor difference is the use of left over Paulonia from my Vember for the shearclamps and cross beams.

Trevor

[nickcrowhurst]

Eskapist, that would be excellent, thank you. As your construction is at 90% scale, you will know that you need to put the paper patterns in a reduced sub-area of 2196 x 1098 on your sheet of 24440 x 1220 plywood. I don't need the optimum cut-line, but I just need to know that the one I've drawn will work for our builder in the USA. I've scaled the dimensions on this drawing:

Many thanks.
Nick

[SteveKe]

Re. Sheathing in Carbon cloth
I just found Simon Ballantine's recent post showing a carbon fibre covered build. I think I might go for it!
S.

[eskapist]

I'm a little later than I said on account of my bread making taking longer than usual! I have looked at my as yet to be decked 90% Shrike and your calculations ( the reduced ones ) allow ample room. Looking at my completed Vember and she's a slightly plumper lady but will still fit within those dimensions as well. In fact, measuring across the widest part of the deck, which includes draping the tape over the raised cockpit rim and not just the ply, the actual dimension is still less 600 mm.
While on the subject of deck ply, I realised that what I thought to be a complete sheet of 3mm for the deck had a great chunk cut off one end and so I was about to order just one sheet, but then saw that the new stock price was 20% up on a few months back. This called for a rethink, because this Shrike is definitely to be my N(+1) boat and I'm trying to use up my hoard of left over materials and as I've got one and a bit Paulownia boards left, this'll be a strip deck Shrike LV . A first perhaps??

Trevor

[nickcrowhurst]

Eskapist, that's very reassuring. I'll let the builder know. Many thanks. The Gallery shows a strip-deck Shrike 100% by Steve in the USA, but you could build the first strip-deck LV. https://cnckayaks.com/2016/08/17/steve- ... -from-usa/
Good work.
Nick.

[nickcrowhurst]

Re. Sheathing in Carbon cloth
I just found Simon Ballantine's recent post showing a carbon fibre covered build. I think I might go for it!
S.

Steve, bear in mind that will make it heavier than just epoxy resin coating (14.5 Kg). The carbon fibre wrap is so that the kayak will put the frighteners on any rock daft enough to get in her way.

[DavidDeWitt]

I have been curious about the all carbon Shrike layup for a while. From my limited knowledge of working with carbon I thought carbon was better used on the inside of a boat where its tensile strength was an advantage and not on the outside of a kayak. When one looks at the layup of a composite kayak carbon is typically not used for the outermost layer. Could you please explain its use?