Sunday, 31 January 2010

New kayak Sedna in progress..updated 24th March

Here's the stage by stage progress of my new strip-build design, Sedna.

I started off by purchasing 21m of clear Western Red Cedar Decking from the Deck Supply Company

I won't go into the construction method in great depth as that has been covered in earlier posts on the blog, but here's the forms on the old strongback....I won't be using it again, it's well past its sell by date now. I am hoping to build this kayak economically and recycling as much old material as possible.

...and the first couple of strips along the sheerline are on.
This time I'm using much wider strips, 24mm and 20mm x 5mm thick and should get it stripped far quicker than last time.
The strips are shaped using a block plane to produce a rolling bevel rather than using bead and cove strip, so glue weight should be less. I'm aiming for a very light boat this time round.

...9th Feb: finished stripping the hull...

17th Feb...the deck is well on the way...the wider strips are making it a much faster build, 42hrs so far. I'm not doing a pointy end this time, a shaped block of maple will be epoxied on later.

Stern view. There isn't enough clearance to fit a Karitek skeg box this time; I'm going to have to manufacture my own design. So far I have used 1/3 of the glue and staples used on the last boat.

Finally finished stripping the deck today, and after a preliminary sanding slapped some filler into the staple holes. The area around the cockpit was a pig to strip. [52.5 hrs]

I cut the hole for the layback today and planed most of the hull and deck to fair the strips, and then a quick blast with the orbital sander. It's a lot different from my other boat, less rocker, narrower, and definitely leaner all round. The cockpit is quite high at the front as I like to have plenty of room to wiggle my legs around; I also have a cunning plan.....[57hrs]

I started fitting the strips to form the layback. For every 3 strips I fit a full length one to keep them aligned and provide support. I'm using cyanoacrylate and wood glue to do it quickly.

I've ordered a set of KajakSport hatch covers and rims. They will add a little extra weight [1.5kg] to the boat compared to the way I did the hatches on Tootega, but I want ones that are easily replaceable and more watertight. Unfortunately they are a lot harder to fit as the rims have to be glued to a flat surface, so some extra creative fibreglass work will be taking place.

28th Feb: layback finished. [76hrs]

1st March: Sanding and filling then removed the deck and hull from the strongback and forms. Out of curiosity I weighed them on a spring scale: 9.5kg!
Allowing for say 6kg max of resin, 2kg max for glass cloth, then fittings, seat and bulkheads, I should be on course for a 20kg boat as planned. [81hrs]

5th March: spent most of the day filling and final sanding of the hull. I gave it a wipe down with a wet sponge to remove the dust and raise the grain. This gives a good idea of the colouring of the wood when resin goes on.

On the way back to the workshop I bashed the stern against the door frame and cracked it. Grrrr!! [88hrs]

9th March: The resin arrived yesterday and having been in a warming cabinet overnight is lovely and thin.
Last night I gave the hull a sealer coat of resin onto the bare wood, and this afternoon I heated the workshop up whilst I draped the 100gm fibreglass cloth over it, and trimmed it to shape.

It's half the weight of the cloth on Tootega and using a varnish roller, I covered it in less than an hour, and used a squeegee to remove the excess resin.

The experience gained from the last boat is really helping; it's easier to estimate how much resin to work with before it starts to thicken, and I'm pleased to say this layup went really well, only one or two tiny bubbles, and only 300ml approx of resin used, which is good!

It wetted out beautifully...

3/4 done. I hardly had a drip. Thin resin is sooo much easier to work with! [90.5hrs]

11th March: Got the glass on the deck today; its quite a stiff weave, and I had to cut a few darts by the cockpit to get it to drape well, but a double thickness will be fine in this area. [92.5hrs]

Been busy recently, here's some pictures of recent work to the end of the hull, softwood blocks are epoxied in which will spread the load for the toggle ropes.
Some people do an end pour with resin but that's heavy

The interior of the hull and deck have been glassed, the cockpit area with a central piece of 200gm cloth [never again, 2 x 100gm much easier to do] and some extra reinforcement to the ends too. I gave them a swipe of fill coat to make it easier to slide stuff inside the boat.
The interior is a lot neater than my previous boat.

I have also laid the keel strip and a couple of filler coats of epoxy to deck and hull.

Next up: sanding...more filling and sanding, building the coaming and the surrounds for the Kajaksport hatches.
[133 hrs / boat weight....12.8kg... materials cost so far: £475]


Mick said...

Hi, Can you tell me the diferance between beed and cove and rolling strips?regards Mick M

Dr Blug said...

Hi Mick,
Bead + cove is when the strips have a round edge and a cup edge routered onto them and they fit inside each other. A rolling bevel is an angle made with a plane which changes along the length of the strip, and uses less glue.
Have a look at
for lots of info on this

eurion said...

Astounded at your new project! But then it's probably just a model on a grander scale for you. I have every expectation that it will me as fine as the first.

Dr Blug said...

Thanks for the thumbs up Eurion.
Having f**k all else to do means I can crack on with this one quickly.
I might as well make the most use of my workshop before the lease runs out [or the roof falls down]!