Building log: planning
Written by Magnus   
torsdag, 31 augusti 2006

Since finishing by last SOF by the end of May, I've been thinking about what to build next. A baidarka, maybe for two? A Yost folder? Or perhaps a "no-brainer" stitch-and-glue à la Nicholas Bertrand? Stitch-and-glue technique appeals to me because not many builders here are doing it, and it seems fast and well suited to do hardshell Greenland hulls. Anyway, summer is meant for paddling, so there was plenty of time to decide.

After arranging (and taking part in) the rolling competition at the Stocken Meet, I decided that I wanted a dedicated rolling kayak. I had brought my Lc.148 replica to the meet, and while it's easy to roll, it can't be characterized as a typical rolling kayak. It's fairly wide (52 cm) and deep (18 cm), and with me in it there's a freeboard of 50 mm. Flat laybacks are a bit painful. My SOF version of the Black Pearl is better in that aspect, being more shallow (16 cm) and less beamy (46 cm), but its length still provides enough volume that the freeboard is about 30 mm. At Stocken I also tried out the Waterfield Qaanaq 512, which is, for a commercial boat, a very nice kayak. The beam and length felt about right, but the front deck is way too high. I've gotten used to paddling with flat legs, so I cramped up trying to wedge myself into the kayak. And there was still some margin for less freeboard...

My goal this time is to hit the "legal" limit of 15mm freeboard. In order to avoid building a submarine, I therefore drew the hull in HULLS, and, given that I want a depth of 12 cm, changed beam and length until I reached the 15 mm freeboard limit. This was for a displacement of 100 kg -- that's me (80 kg), clothes, pfd, paddles etc (10 kg), and the kayak (10 kg). Yes, that's right: I'm aiming to build light: 10 kg. It's certainly possible if I find the right wood, a 8 oz nylon skin, and a minimalist approach to the frame. This kayak will never see high seas, so I'm "under-building" it, and I've reduced the number of deck beams and ribs to a minimum. I view it as an experiment. I know that Harvey Golden has built some really light kayaks, and while I am nowhere near his experience level, I can at least give it a try!

Having found the dimensions, I re-drew the hull in Illustrator and distributed deck beams and ribs. I build faster with a drawing to refer to for measurements. It also makes calculating how much material I'll need a bit easier.

The frame for this kayak will have only 9 deck beams (masik included), and 15 ribs. Traditionally this varies greatly, but usually one would see 12 deck beams and 20-25 ribs. I have widened the ribs, from the 25 mm that I've used before, to 35 mm. There will be almost no rocker. This will give me an extra cm around my large feet, and rocker isn't really needed in a short rolling kayak. I'll be sitting right on the skin, perhaps with a pad -- there will be no room for floorboards in this one (something that I've never found useful, by the way).

To sum things up:

Length: 510 cm

Beam: 47 cm

Depth: 12 cm


Comments:

Johan
Hejsan. 
Lite nyfiken vad kostnaden för en sådant byggprojekt stannar på. Jag tänker då egentligen endast på materialkostnaden. 
 
MVH 
Johan
Written by Gäst on 2006-09-20 13:34:25

Kostnad
Jag räknar med ca 800 kr för virke, 600 kr för duk (nylon), och ca 1200 kr för polyuretanlack, samt ett par hundralappar för förbrukningsmaterial: penslar, maskeringstejp, najgarn etc. Gott och väl under 3000 kr, alltså. Har man tillgång till bra drivved blir det ännu billigare...
Written by Magnus on 2006-09-20 13:48:59

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