Monday, 16 June 2008
Saturday, 10 May 2008
Unusual design for multi-purpose kayak
- mostly for use in sheltered water
- mostly for exploring as opposed to long journeys
- wants high initial stability
- must be very manoeverable for playing in small creeks and inlets
- must be able to track well when required for straight line journeys
- needs lots of foot room: feet must be able to be vertical
- lightweight so easy to car-top and carry around.
She has seen some commercial kayaks which are possible but I thought I'd look at building one as an alternative. Something like the skin on frame is possible, and that might be a good option. But I also remembered the Mini Benny by Duane Strosaker (although mention of it now seems to have vanished from his website - I don't know why) which looked interesting, for its small siez and planing surfing ability, and then I came across the Rockhopper too. This second one in particular seemed to meet a lot of the brief, while going further too: looks great in rough water and surf. We get plenty of that too, so being able to deal wih it looks like a great bonus.
Rolling all these ideas together I've come up with a possible design. Loads of rocker, very U'd bow, completely flat towards the stern and with a transom. It feels like this might tick all the boxes.
- Short length, lots of rocker, U'd bow and flat bottom aft hould all mean very manoeverable.
- Short length = light and easy to handle out of the water. Plus, wooden constrution is almost bound to be lighter than the polywotsit commercial alternatives.
- Will probably track positively as is, with the hard chines in the aft half compared to the U'd front half giving some directional stability, but I can also add a retractable skeg to increase tracking further.
- Fairly wide, and flat bottom, will give high primary stability.
The looks have also grown on me since I designed it: I really quite like the odd transom now. I've been tweaking the design for a while and have pretty much settled on it as where I was trying to get to. Decision time: do I build it or not?
(No, I haven't finished the SoF, an I also have a Selway Fisher Prospector open canoe on the go for my brother and his family ;-)
Sunday, 30 March 2008
Skin on Frame
I wanted something that still looked an behaved like a Sea Kayak, but was as short as I could reasonably make it. I ended up at just over 4 m / 13.5 ft, with a 60cm / 24" beam.
I used the Tom Yost ply frames technique (www.yostwerks.com - thanks Tom), and DelftShip to design the original shape. The ply forms take a little while to cut out, but then, if you have decent wood which will bend without breaking, assembly is super-fast. I was making this one as a trial, since the wood was bad and I wasn't certain about the design, so I only tied it all together - no glue, pegs, screws or anything. It was plenty strong enough.
For the first trial (on the open Irish Sea I should add) I covered it in cling film (saran wrap). Despite 6 layers applied tightly it started to leak immediately (not a suprise), but after a few minutes was leaking faster and faster as the film stopped clinging! Still, it did the job before a hurried return to the beach - I knew that it basically worked but some modifications were needed, to improve the manoeuverability. Extra stringers were added between keel and chine, to remove the previous deep scallop whichg develops on a wide hull like this and to give a slightly rounded bottom. The bottom of the stem was also rounded off.
A second trial the next day, covered in garden centre polythene, was much better. No seams so no leaking, a smoother surface meaning it was faster and just felt better, and much more manoeuverable. Pretty much what I was looking for. Even more manoeuverability wouldn't go amiss, but it is only 4.16m / 13.6ft long, so I need to be careful to keep some tracking still, it would be all too easy to lose that completely.
What next? Well I think the experiment has worked, so I'll rebuild it with nice wood, and finish it off properly.
Monday, 12 November 2007
Did my first balance brace - the new kayak does indeed make them very easy.
Spent a few hours surfing in very clean waves - after a good blow to set them up, the wind flicked offshore in mid afternoon as a front came through, and the offshore wind held the waves up beautifully into clean faces. As the tide dropped the rides got longer and longer.
Only downer was failing to roll back up from the one time I got tipped over. Bit disappointing after all the rolling practise. The problem was remembering what to do - I clearly need to practise setting up underwater after tipping in in lots of different attitudes, not just rolling over already set up.
No pictures sadly.
Lots of admiring comments about the kayak though. Less so about the paddle - much scepticism about whether it really had the power to deal with the tides we get round here. It doesn't help convince people when they try it for a few strokes and find it fluttering all over the place. Lots of interest though.
Tuesday, 25 September 2007
- It rolls very easily: I managed my first ever roll to the right on my first attempt, then proved it was no fluke by following up with my first rolls with the greenland paddle held in normal paddling position (unextended) to the left and right, again first time each way.
- I'm sure it will balance brace with a tiny bit more practice: I was only having to scull very gently to stay in place, I bet if I'd stopped I'd have balanced. Next time...
- It surfs like a champ. I can't claim the credit cos I've never had much luck surfing kayaks in the past, they've always tripped up or screwed off sideways, so it must be the boat. I never felt like it was about to trip up over a chine - maybe the deep V forward meaning the chines are softer than they might be helps? It picked up and surfed easily on the (decent sized) waves and swells in the open sea as well as in the waves on the beach.
- It has just the slightest tendency to weathercock if you look for it, but can be held in a straight line with no real noticeable effort when you're paddling.
- It behaved very well in waves, being easy to hold a course in any direction to the waves, including with a quartering sea from behind. Sure, it squiggles about a bit as big waves pass through, but there were no nasty suprises and overall it kept going in roughly the right direction. Still plenty more testing to do on this one in different waves, longer trips.
- As previously reported, it does carve turns, although not super strongly.
- Oh, it also attracts admiring glances!