Shrike, a lightweight sea kayak for home construction.^

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

Post by Graham T » Wed May 22, 2019 12:56 pm

now I think that is very cool and stylish

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Archipelago Folk School course - 6 more Shrikes, Isle of Mull

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

Post by PlymouthDamo » Wed May 22, 2019 2:30 pm

I appreciate Greenland sticks are a bit 'marmite,' but surely we should respect individual preference and certainly shouldn't be beheading someone just for going against the prevailing view.

Very impressive by the way. Going from nothing to a self-built Greenland boat in a week must feel like such an achievement for those guys.

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Fine painting in Luxembourg today

Post by nickcrowhurst » Fri May 24, 2019 11:59 am

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...and PlymouthDamo, beheading may seem rather harsh, but you can see that the guy (or gal) on the course is actually stamping on the Euro Paddle.

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

Post by almorris1 » Mon May 27, 2019 10:31 am

We'll I finally got a print, from Pointserve in Belfast. Thanks for the other recommendations, but they proved to be fruitless. 3mm ply arrived from Robbins + my epoxy also from Belfast.

Any recommendations for the deck fittings? I'm leaning towards stainless steel t the minute but am open to other solutions.

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

Post by nickcrowhurst » Mon May 27, 2019 11:27 am

Al, I presume you have looked at the four options described in the Build Manual (pages 30 to 35 in the latest revision, March 2018) We use our 3D printed deck fittings, usually in Nylon.There are at least five FabLabs (https://www.fabfoundation.org/) on the island of Ireland, where the public can use a 3D printer and produce the fittings at low cost.
I have had excellent results printing plans from Servicepoint, as described on our website after a recommendation from JIm on this forum. Did you try Servicepoint? If they no longer supply plans I'll get our website amended.
Nick.

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

Post by almorris1 » Mon May 27, 2019 1:28 pm

Hi Nick, Servicepoint in Belfast did the printing, although a detailed email + phone call are required. I think for the money involved most printers don't seem interested.

As for fittings, I've yet to look at the 3d prints.

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

Post by Mowgli » Mon May 27, 2019 8:36 pm

You can make Maroske fittings with some 20mm braided carbon (or fibreglass) sleeve, epoxy, and some 12mm latex tube to keep it open as the resin sets. It's a bit fiddly but looks good when finished.

https://www.easycomposites.co.uk/#!/fab ... ded-sleeve

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

Post by nickcrowhurst » Mon May 27, 2019 9:09 pm

We used to install these, but they are tricky to get right. Great care must be taken to remove all the resin from inside the tube. We've also found the occasional one that leaks, and then it's a game to seal the leak, which is why we now use 3D printing. The Shrike Build Manual (revised March 2018) at page 34 states:

We like the visual simplicity and elegance of Maroske deck fittings, but they are anything but simple to construct. Google “Maroske fittings”.  It can be a struggle to pull the PVC tube out after the epoxy has set. To make it easy to extract the tube We first put the wire inside the PVC tube, then wrap the PVC tube with PTFE tape, and then insert the PVC tube into the fibre-glass sleeve. This entire assembly is then threaded through the deck. We use fiberglass tape over and under the sleeve to spread the load, and then thickened epoxy smoothed over the entire assembly. The PTFE tape makes the PVC tubes easy to extract after removing the wire. We use a bottle cleaning brush to remove any remnants of PTFE that stick to the epoxy.One way of producing lightweight Maroske fittings is to bond in a semi-circle of 3 mm plywood. This minimises the use of the heavy epoxy, and also produces an even curve, thereby facilitating the eventual withdrawal of the inner tube.

We also install the deck fittings before the deck is glued in position. This saves a lot of contortions (and swearing).
Nick.

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

Post by almorris1 » Tue May 28, 2019 7:23 am

Hola, can somebody point me in the direction of the 3d prints? I can't find them and I'm think I've the latest version downloaded. March 2018

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

Post by nickcrowhurst » Tue May 28, 2019 8:03 am

Al, I'll sort that later this morning.
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Re: Shrike, a lightweight sea kayak for home construction.^

Post by Oisin » Tue May 28, 2019 8:40 am

Thanks for the info on the fab foundation Nick I must have a look at that, commercial providers were quoting about 10 euro per piece when I was looking about 2016.

I was looking at surfboard leash plugs as plan b

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

Post by almorris1 » Tue May 28, 2019 10:27 am

Oisin, plan b looks good if you can get the right size. I imagine too big would look clumsy.

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

Post by nickcrowhurst » Tue May 28, 2019 11:21 am

Al, one can neither attach files to a forum post, nor to a PM, but If you want the data file (.stl file extension) today then PM me your email address and I can send it to you. Otherwise I will get the .stl file added to the download this weekend.
Oisin, the commercial 3d printing is indeed far too expensive, but the extra bonus with FabLab, apart from the low cost, is that one gains knowledge and experience, and that, for me, is priceless.
Nick.

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

Post by Chris Bolton » Tue May 28, 2019 1:34 pm

nickcrowhurst wrote:one can neither attach files to a forum post, nor to a PM
That's correct, but you can upload a file to the web and insert a link to it. I don't think there's any restriction on the kind of file you can link to; if the file type isn't recognised by the browser it will just offer to download it.

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

Post by nickcrowhurst » Tue May 28, 2019 3:01 pm

Chris, I tend to work in the cloud, and back-up to my PC, but Dropbox (my cloud choice) unfortunately stopped the public sharing of files a couple of years ago. Sharing to particular email accounts is still enabled. I could doubtless open another cloud account elsewhere, but I currently have a LibreCalc spreadsheet which already contains my 171 account names and coded mostly-unique passwords. It does my head in! Perhaps I should sign in to "True Key", or similar, but I'm reluctant to put all my eggs into one hack-able account.
Nick.

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Isle of Mull, last week

Post by nickcrowhurst » Thu May 30, 2019 8:04 am

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Christian in Luxembourg on his maiden voyage

Post by nickcrowhurst » Tue Jun 04, 2019 9:48 pm

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

Post by almorris1 » Sat Jun 22, 2019 7:50 pm

Help please. I have inadvertently cut my 3mm plywood panels (all 10 ) at 214 mm as opposed to the correct measurement of 244 mm. After realising this I cut a 60 mm strip thinking I could insert this between the 214 mm panels.

1. Is it feasible to insert a 60mm panel at the bottom of the hull and what effect will that have?

2. What of the topside panels? How much lower in height can I go from the 100 percent template I printed?

3. Buying 2 more panels is a non floater.

Thanks.

Al Morris

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

Post by nickcrowhurst » Sat Jun 22, 2019 8:54 pm

Al, do not despair!
I've been in bed for 4 weeks with pneumonia, but I'll check my response tomorrow when my brain should be working a little better. Meanwhile, a few quick thoughts:
1. The panels can be re-constituted by simple butt-strapping, reinforced both sides with glass tape and resin. I would add 30 mm to each. I don't understand "60 mm in the bottom"
2.Topsides are reduced by 60 mm in one of our rolling Shrikes. 30 mm will be fine as long as your weight is not too high. You might need to have a high masik to compensate. Send me your height, weight and shoe size and planned use of the kayak and we can talk about it. You can PM me if you wish.
We all screw up sometimes.
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Re: Shrike, a lightweight sea kayak for home construction.^

Post by PlymouthDamo » Sun Jun 23, 2019 9:17 am

almorris1 wrote:
Sat Jun 22, 2019 7:50 pm
Help please. I have inadvertently cut my 3mm plywood panels (all 10 ) at 214 mm as opposed to the correct measurement of 244 mm. After realising this I cut a 60 mm strip thinking I could insert this between the 214 mm panels.

1. Is it feasible to insert a 60mm panel at the bottom of the hull and what effect will that have?

2. What of the topside panels? How much lower in height can I go from the 100 percent template I printed?

3. Buying 2 more panels is a non floater.

Thanks.

Al Morris
If I were you, I'd get the paper templates printed out and then lay the panels you've cut over them to see what 'gaps' are left - i.e. where the panels don't cover the boat's outline. You'll probably find that there's only a small amount missing. Then you can stick your panels together length-ways and graft on the extra bits of ply along the edges (all done using the 'butt-strapping' method that Nick mentions.) It's dead easy - you just line up the straight edges on the two bits of ply you want to join, and use epoxy to stick fibreglass tape over the crack. Once dry, turn over and do the same on the other side. Then drag a stanley knife blade along the edges of the hardened fibreglass tape to bevel off the square edges. Bevelling off the edges means tape will then become completely invisible when you apply the final layers of epoxy/varnish to the finished boat.

I've built Nick's rolling Shrike with the deck lowered by 6cm and I love it - it rolls incredibly well, but has zero secondary stability. My mate has built a Shrike lowered by 3cm and I think that's the perfect compromise - personally I think it's much sexier than a full sized Shrike, but not too extreme and retains a bit of secondary stability. However, even if you decide to reduce the deck height, you'll still need full-sized panels for the bottom of the boat so you might still have to add plywood to some panels.

You'll need to repair the panels now, rather than 'filling in' gaps at the end, because the complicated curved shape of the boat comes about by joining the edges of all the shaped panels together.

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

Post by nickcrowhurst » Sun Jun 23, 2019 9:58 am

Al, Damian is on the money, as always. Follow his excellent advice and you should be fine. When you joint the edges of the strips, make sure you use factory cut edges where possible, and use super glue with accelerator to tack the edges together before taping:
https://bit.ly/2J3uQUO
Where you will be putting your feet down onto a joint in the cockpit, and under the seat, make sure to strengthen particularly the outside of the panel joint. Two layers of glass would be good.

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

Post by almorris1 » Sun Jun 23, 2019 10:39 am

Thanks Damien and Nick for the response.I was going to charge ahead but wasn't sure where to charge too.

I'm not big into expedition type kayaking so wasn't overly worried if she ended up around 90 per cent full size. Live and learn.

Nick, rest easy and rest well.

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

Post by Oisin » Sun Jun 23, 2019 8:36 pm

Hey,

Hope you're on the mend Nick!

Can I ask what size hatches people have fitted to their boats (Shrike too in particular); for the large front/back compartments do sea kayaks usually have 10 inch round, 20 inch oval etc?

Found a very local makerspace with 3d printers through the fab foundation, thanks for that advice!

Thanks,

Oisin

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

Post by nickcrowhurst » Sun Jun 23, 2019 9:40 pm

Oisin and Al, thank you for your good wishes. I am truly knackered.
There is a great range of hatch styles, sizes and layouts and you can see them in the Gallery. I don't put a hatch in the foredeck, but I put one in the foot bulkhead, unless the kayak is for expeditions. I try to fit two hatches in the stern, the largest that will fit, usually 8" (10" if I can squeeze it in), one in the day compartment and one for access to the skeg mechanism. An example of a day kayak is the 4th one in the Gallery,here, from Neal in Devon:
https://cnckayaks.com/shrike/build-gallery/
There is plenty of hatch information in the Build Gallery and its Builders' Tips Appendix.
Have fun with the build.
Nick.

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John, yesterday, in Scotland

Post by nickcrowhurst » Mon Jun 24, 2019 9:09 am

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

Post by Spikeedog » Mon Jun 24, 2019 12:57 pm

...and it handles really well.

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Vember Expedition version

Post by nickcrowhurst » Sat Jun 29, 2019 5:03 pm

Vember is a round bilge development of the Shrike, and Vembex is Damian's lengthened expedition version of Vember:

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Bjorn Welin from Sweden just completed this beauty.

Post by nickcrowhurst » Thu Jul 11, 2019 7:03 pm

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

Post by Beryl » Thu Jul 11, 2019 9:58 pm

Has anyone tried home-built hatches just secured with an internal bungee? I can imagine problems but they look very slick I have to say....

https://youtu.be/kg7QfGQL1zk
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