Shrike, a lightweight sea kayak for home construction.^

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

Post by Spikeedog »

I used a modified wooden egg cup and stainless steel rod mounted on a wooden plate that sits under the deck. Works and looks great.

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

Post by nickcrowhurst »

Oisin wrote:
Thu Sep 19, 2019 1:03 pm
The local 3d printing route hasn't worked so I've been looking at surfboard leash plugs, mock up in the pictures above. 20 of those are very inexpensive.

I can drill the hole with a forstner bit and have a backing plate under the deck I think
Oisin, that looks to be a good solution, provided it can be secured strongly. In a rough water capsize and wet exit, a single fitting would need to be strong enough to take a shock loading of the paddler's weight. How do you plan to strengthen the fitting against a high upward load? On a GRP surfboard one can laminate glass cloth and resin into the grooves below the surface. Would you plan to do this, or perhaps to insert small pieces of plywood to achieve the same object?
Thanks for the input.
Nick.

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

Post by nickcrowhurst »

Spikeedog wrote:
Thu Sep 19, 2019 6:49 pm
I used a modified wooden egg cup and stainless steel rod mounted on a wooden plate that sits under the deck. Works and looks great.
Spikeedog, that's a good solution. I guess beech is a suitable timber: https://bit.ly/2kW3cRE
Nick.

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

Post by Spikeedog »

I think those were too small. The oned I used were about 3" wide but beech and a plywood Base plate with a good length of stainless steel rod to spread the load.

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

Post by mcgruff »

nickcrowhurst wrote:
Fri Sep 20, 2019 9:25 am
In a rough water capsize and wet exit, a single fitting would need to be strong enough to take a shock loading of the paddler's weight.
For hammock suspension, the rule is to use cord etc rated at least x5 the person's body weight to cover shock loading & any weakening from knots or splices.

Presumably a kayak leash (and fittings) would need to be at least this strong. There's the same inertial mass to accelerate plus the water resistance of the human sea anchor being dragged through the water.

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In Luxembourg.....

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In Luxembourg, a young lady glasses the hull. This will be the second Shrike in her family.
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Re: Shrike, a lightweight sea kayak for home construction.^

Post by Beryl »

On the subject of leash to attach kayaker to boat... I’ve been worrying this as most places on the Shrike are only 3mm thick. You could use the Masik I suppose but that puts the safety cord in your lap with possibility of entanglement. I’m thinking a solution might be an external cord attached to the stern. You have the solid wood of two gunwales, possibly already drilled for a lifting grip and the advantage that the dead weight of the kayak will not be side-on.
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Courses for Shrike building anywhere in the U.K

Post by nickcrowhurst »

Chris at Selkie Kayaks has a novel idea. If you can get together a group of 4 to 8 fellow paddlers, and supply a suitable venue, he will supervise a 9 day course, at the end of which you can each go home with a completed Shrike for £1,000. That includes anywhere in the U.K: https://selkiekayaks.co.uk/9daycourse
There are initial plans for a series of such courses in Norway.

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A Shrike under construction in Italy

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Federico from near Turin, Italy, is making good progress:


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

Post by craigx »

downloaded the designs for these beautiful kayaks yesterday and spent the day reading the manuals. I really like to make one of these, but my garage is only 16 foot long. So i need to reduce the length to 15 foot somehow. What would be the consequence of doing this to the vember design by moving the First and last stations and minor adjustments to others. I am 185lb so need to keep the free board for the standard kayak. I prefer the shrike design but feel that alteration to this may be more problematic.
Anyway, thank you for the designs. It has been very thought provoking and given me a Good read.
Craig

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We need to talk....

Post by nickcrowhurst »

Craig, I will need to do some calculations before advising you. Meanwhile you could use the PM system via the contact point to the right of each post to tell me a little more about your kayaking experience, type of paddling envisaged, etc.
Keeping all other variables constant,(which you can't), reducing length will reduce stability. Moving station points is a complex area, so we need to discuss this.
I'm very pleased that you are planning to build one of our designs. Shrike is of pure West Greenland heritage, exciting and responsive to every paddle stroke, while Vember is a Shrike with the sharp chines rounded off, giving a more steady stability curve.
Nick.

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Stefanos from Greece is making progress

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Smooth lines and good work from Stefanos in Greece. This is the 216th confirmed construction of a Shrike.


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

Post by Beryl »

Nick, I’ve been thinking at some point of trying a sail on my Shrike. Could you put up some thoughts on this? I’m thinking it’s easier to do any mods as I build the boat even if it’s just a simple reinforcing strut under the deck for the sail base. Thanks.
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Re: Shrike, a lightweight sea kayak for home construction.^

Post by nickcrowhurst »

As you suggest, the only part of the sailing rig that cannot easily be fitted after the hull and deck are completed is a strut down from the mast step to the keel. In my case, I fitted a second skeg in the bow to improve windward performance, and the mast step is supported by the skeg box. To retro-fit the forward skeg box I installed a forward hatch just large enough to insert the skeg box. You could fit a forward hatch to enable a strut to be fitted. A reinforcing pad of plywood could also be fitted under the deck after dry-fitting the foredeck, but before gluing it in place.

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Peter M's lunch stop on the Fowey River, Cornwall

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David from Boston, USA, is building his Vember

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Alec from Romania with more original variations on Vember.

Post by nickcrowhurst »

Alec Naneti from Romania already has a foam 3-part Shrike in our Gallery: https://cnckayaks.com/2017/12/14/alec-n ... m-romania/
He has now applied his skills and original thinking to use cheap foam to build for a child a 75% scale round-bilge Vember in strip foam, and then to make it 3-part:

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https://photos.google.com/share/AF1QipO ... 82eGJlR1dR

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Robin from Ontario, Canada, presents his new Shrike

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The 218th confirmed Shrike construction:


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Frederico launches his Shrike

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Frederico,in Italy, on his Shrike's first day afloat. His comment in his email today : "amazing."

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Another Shrike (95% scale) from Russia.

Post by nickcrowhurst »

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From Serg, in Southern Russia:
My first experience building a kayak. The construction took 15-20 days for 3-4 hours, the budget is about 15k, while the resin was left for another project. It remains only to paint the cockpit and embed the hatches.
Some technical information:
FSF 4mm plywood, T-13 fiberglass, Etal375 resin, Etal45M hardener.
External coating - acrylic enamel, spray paint application, adds 200gr to the weight (25% dry residue).
95% scale (adjusted to paper size) despite this At my weight of 90 kg the kayak is held very high and it feels like it can hold up to 30 kg of equipment.
For those who are going to build, do not forget to buy a 50mm glass tape! Cutting the fabric into strips and then getting confused in rags mixed with resin was the most unpleasant part of the job.

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Today's email from New Zealand

Post by nickcrowhurst »

David from New Zealand has today completed a Vember for his wife, to accompany him in his Shrike:


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

Post by Oisin »

nickcrowhurst wrote:
Fri Sep 20, 2019 9:25 am
Oisin wrote:
Thu Sep 19, 2019 1:03 pm
The local 3d printing route hasn't worked so I've been looking at surfboard leash plugs, mock up in the pictures above. 20 of those are very inexpensive.

I can drill the hole with a forstner bit and have a backing plate under the deck I think
Oisin, that looks to be a good solution, provided it can be secured strongly. In a rough water capsize and wet exit, a single fitting would need to be strong enough to take a shock loading of the paddler's weight. How do you plan to strengthen the fitting against a high upward load? On a GRP surfboard one can laminate glass cloth and resin into the grooves below the surface. Would you plan to do this, or perhaps to insert small pieces of plywood to achieve the same object?
Thanks for the input.
Nick.
Could the basic fitting of webbing and a single screw through the deck into the sheer clamp take a shock load like that?

I've made up a rough sample fitting from the surfboard leash mount where its epoxied into a plywood canister that then gets glued under the deck, I need to test out a shock load with it.



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The surfboard vents for the bulkheads were glued into place


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

Post by nickcrowhurst »

[Could the basic fitting of webbing and a single screw through the deck into the sheer clamp take a shock load like that?
Oisin, a single screw thread into solid wood always impresses me with the load it will take. If one screw pulls out, it is linked to the fittings on either side by the grab line. A screw pulling out is unlikely to damage the deck and make the kayak unseaworthy, just when you are in rough water and perhaps in survival mode. However, one disadvantage is that as the round screw heads are close to the edge of the deck, they have proven to be liable to damage your buddy's kayak during the recovery. A deep scratch on your partner's shiny GRP deck is not good for inter-personal relationships. Wider sheer clamps would lessen this, but this would add weight to the kayak.
We get round this by using our 3D printed deck fittings with the large nylon under-deck integral plate to spread the load laterally. Adding your plywood discs under your fittings would not, IMHO, spread the load across a larger area of deck. One solution would be: On the workbench I would use thickened epoxy resin to glue the egg-cup to a 3 mm plywood pad with the hole already Forstnered in it. The pad could be perhaps 100 mm x 75 mm with the corners rounded off. You then have an egg-cup with a plate, ready to epoxy glue to the underside of the deck, again with the hole already cut. The hole in the deck would need to be slightly smaller than the egg-cup, so that the egg-cup is trapped under the deck, rather than relying on just the glue. I believe that would work.
All the best, from Nick.

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

Post by Oisin »

Thanks for that response Nick will take it on board

Sent from my FIG-LX1 using Tapatalk


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nickcrowhurst
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Hotel art

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The USA Marriott hotel chain commissioned a local artist to build a Shrike to be the art to decorate the entrance lobby of its latest hotel in Minneapolis, Minnesota, USA.

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

Post by rockhopper »

i guess it's shame it's not being used....that said, it does look beautiful as a piece of art..!

Rog.

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First coat of varnish

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David in Boston, USA, sent this photo today. This is a view from the stern of his Vember. Note the green tape masking off the skeg slot.

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

Post by nickcrowhurst »

Craig from Sussex UK is progressing well with his Vember:


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

Post by charleston14 »

A most comprehensive Shrike build video 40+ mins long


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

Post by nickcrowhurst »

Thank you, charleston 14. The Berger Boote website has today included, in German :

"The Yura was inspired by a design from https://cnckayaks.com and is licensed under Creative Commons Attribution 4.0 International License. On the CNC-Kayaks website, Chris and Nick Crowhurst provide free blueprints for a number of great kayak designs."

https://www.bergerboote.de/shop/Yura-p132014545

Nick.

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