Before the maiden (!) voyage, a quick head 'transplant' !! I'd like to introduce 'Katie the Kayaker' 😂🤣

It was with some trepidation that Katie was carefully launched onto the Buxton lake. An ideal day last weekend with very little wind. I knew she would float, but would she move, and be controllable? Well the answer is yes - sort of 🤔

Thanks to Philcaretaker for the video clip.

She managed to paddle out, turn and paddle back, which was a great start. At least she didn't need rescuing. Shame she wouldn't keep hold of the paddle!

The paddle blades are not feathered at the right angle. The starboard blade is at the wrong angle and is hitting the water causing the kayak to rock excessively from side to side.

Once back on dry land, the kayak was checked inside for water. There was just a drop but nothing to worry about, which was also a relief.

So, overall it was reasonably successful, but several teething problems to be resolved before the next outing.👍

I wanted to keep the paddle shaft in one piece for strength, but while undergoing 'sea trials' it has become clear that a means of adjusting the feather angle between the two paddle blades is essential. Accordingly, a brass coupling was made on the lathe. It comprises two pieces which screw together with a knurled locking nut. The paddle shaft was cut into two halves and epoxied into each end of the coupling. The two halves can now be adjusted to set the blade feather and locked in position.

The other problem during the first outing was Katie letting go of the paddle. Whilst this gave an impressive demonstration of one, or even no, handed paddling, it wasn't very realistic 😂🤣. Loops of elastic cord were added to keep her hands on the paddle.

The paddling action is produced with a combination of mechanics and software control. A few changes were made to the software to improve the ability to steer. There is still more to be done to improve this. If you watch carefully at 0:35 seconds in the video, you can see the rudder compensating for the paddle stroke to help keep Katie moving in a straight line.

Sorry the video is a bit jerky in parts with my camera mounted on the transmitter. I expect Phil may have something better to show, once he has had time to edit it.

I can't believe it's been two months since my last update to this blog. I haven't been idle though and have continued to tweak the paddling mechanism and the control electronics.

The latest tweak was to increase the size of the rudder as I had foolishly made it the correct 'scale' size, forgetting that water doesn't scale and a model rudder needs to be larger than scale. Anyway, I glued a bit of clear plastic on to the wooden rudder with double sided tape as a trial and it has greatly improved the turning circle. Now I just need to make a wooden replacement to replace the plastic and sticky tape version. I'm also part way through making a 'fancy' paddle to replace the test paddle, now that I have the blade feathering angle worked out.

Here's a short video clip of the latest outing yesterday:

The original rudder was made to "scale size" (1/6th). It worked, but the turning circle wasn't great. I attached a piece of plastic to the rudder with double sided tape to try the effect of a bigger rudder, and as expected, the maneuverability of the kayak was much improved, even if the appearance wasn't 😆.

A replacement rudder made from western red cedar looks a lot better. The shape ensures that the increase in size is not visible when the kayak is out on the water.

Having gained some experience with the test paddle, and having worked out the feathering angle needed between the two blades by trial and error, its time to make a fancy replacement.

Some cedar and pine were cut into strips and glued to produce a striped blank. This was then cleaned up and cut using a bandsaw to produce four blanks taking care to ensure that the stripe pattern lined up. A shaped sanding block was used to sand a curve into the blades which were then glued to a redwood shaft and cut to shape. Lots more sanding was needed to thin the blades and blend the joint between the blades and the shaft. Once the sanding was finished the blades were strengthened with a layer of lightweight glasscloth and epoxy on both sides, followed by 3 coats of yacht varnish.

The new paddle is slightly longer than the original, and the blades are also a little bigger.

A short video, courtesy of 'philcaretaker':

It's been a while since my last update!

Up to this point, the kayak mechanism has been largely mechanical as shown in the first two photos. The trouble I find with such mechanical solutions is that to make adjustments to the action requires making new parts. This is often a trial and error process which takes a lot of time and leads to much frustration. I much prefer to use multiple servos with software in a microchip to coordinate the servo movements to achieve the desired effect. That way, changes to the action can be made quickly and easily by adjusting the software. Quicker changes and less frustration, at least for me.

So, I've put together a new, servo based mechanism for the kayak as shown in photos 3 and 4. This uses 6 servos to produce the paddling motion.

A recent video from RCsailing includes clips of Katie paddling the kayak with this improved mechanism