Friday, 22 September 2017

Rebuilding the Alacrity

The Alacrity
The boat in question was built in a hurry in 2010 in preparation for a class in which a couple of boats to this design were built. It was my version of the Brian Schultz Ginnyak, some six inches longer with a finer bow so as to be able to negotiate a chop better - which was a problem he had identified with his design.
I had re-covered it in late 2012 for the 2013 Anglesey sea kayak symposium but with two hatches and two foam bulkheads; the boat was never so good after I did this and I abandoned bulkheads altogether a couple of years later. For a number of reasons, I came to consider that they were not really compatible with skin on frame kayaks (good subject for another post).

Why rebuild the Alacrity?
A few reasons; it hadn't paddled straight for over a year or so, it was a bit too tippy for me to use much in any kind of a sea - I like to be able to relax a bit these days. I was never happy with the enamel paint coating of the polyester fabric being prone to leakage - there was always some water coming in. Because I was unable to sand down paint on top of fabric, it was not possible to over paint the original coating of 2012 (the broken fibres form a rough surface with the next coat of paint).
Most of all I wanted to try out some design improvements I had incorporated into the Lowen plans that I was producing, particularly the arrangement of the bow assembly. Through re-building with frames rather than steam bent ribs, I also thought that I could improve the design with some developments I had incorporated into the Lowen.

Stripping
One of the best things that can be said for an enamel paint coating was the ease with which the skin could be cut off a boat:

The skin weighed 3kg
and flat on the floor looked like this:
The bow of the frame had gone quite mouldy
Although there was a small soft area, most of the wood was good enough. There was probably no air circulation in such a restricted area, and as skin on frame boats are generally stored upside down, moisture would have collected there. Fortunately I generally use Cedar which is one of the better species for rot resistance, for the bow and stern plates. However there were some lessons on design practicalities here to be learned. The stern section was also damp but perhaps as it was not such an extreme shape as the bow there was no mould or soft wood:
On looking closely at forward quarter of the frame I noticed that three ribs had been pushed across to the starboard side of the boat to the extent that one had broken.
This may have been the cause of the directional instability and also the slight hogging of the keel at this point. Otherwise the frame was not looking too bad:

You can see the bulkheads still in place. Now to work out what to do next!


Sunday, 10 September 2017

Trying out the paddle

First outing on Stithians Lake
Short and not that satisfactory in rather shallow water so as not to get in the way of the windsurfers etc. Thus the boat was quite hard to push through the water. Although the paddle was quite long at 227 cm it  seemed longer: there was a lot of power to use. Not so good was the way it roughed up. It shouldn't have done that. I realized that this was due to the fact that the existing and near empty tin of Deks Oljie had thickened up through evaporation etc and the application had not penetrated like it should. A new tin at a Brexit Sterling price was a stark reminder of a dismal future but its contents did the trick.

Second outing in Mounts Bay

Had I not been testing a new paddle I would have launched at Godrevey on the North coast. There was a beautiful swell 4ft plus that had all the hallmarks of hurricane origin but I didn't like the look of it and I opted for the south coast so as not to risk breakage on landing. I later heard that thirty miles to the north two fishermen were swept from rocks to their death that same day.
The picture shows the boat and paddle at the end of the paddle on an ebbing tide. I had launched from the high water beach of fine gritty shingle which jammed the skeg in its box. The wind was a F3 and there was the ghost of the north coast swell coming through from the west so although lively the boat was manageable.
I tried to record speed and distance on my smart phone; once again it would not work with wet fingers on the outside of the cover. I will not try again, but instead make more effort to remember to put new batteries in the GPS and also revert to my old push button model which did work in a cover, is lighter, and would be able to make important calls when required.
I paddled straight out from Long Rock and then turned towards St Michael's Mount, the swell which had wrapped round Lands End increasing proportionately as I moved east.
I was much happier with the grip on the paddle, grippy but not rough, as it should have been. I frequently turned the paddle over in my hands for reasons which I will explain later and there was no discernible difference in handling.
I couldn't help thinking that this was the ideal stick for paddling a fast boat like the Inuk, being the most powerful GP I had used. I was particularly pleased with the catch.
I consider the poor performance in this area the chief drawback to what is - as far as a Greenlander is concerned a design classic. Speed was not an issue when it came to hunting seals. However for recreation, we have come to expect power at the catch from modern paddle designs.
I had hoped to remedy this somewhat in the GP with this design. However to substantiate any claims I would need to test this or another paddle again with a GPS and heartbeat monitor against my other modern paddles.
The good length of the stick also helped remedy the vagaries of a flat bottomed skegless boat.
The paddle design
Replacing the ornate hardwood tips with epoxy class reinforcement provided an opportunity that previous paddles had not, which was to thin the tip considerably:
so that it is thin and flat as shown below.
This gives two advantages, ease of entry and increased power from the flat section which with a powerful downward component to the stroke (on which modern racing technique is based) a ram effect is produced to lock the blade momentarily whilst the boat is pushed/rotated past it. I was able to eliminate flutter by going straight from flat to a rounded "V" - this can be seen on an earlier picture in the process before the tips were fully thinned.
I will concentrate on building this kind of paddle in the future. A quality modern interpretation of the classic Greenland design.

 There was just one problem with this particular paddle though, which did not become apparent until I studied the picture of the completed paddle shown below:
The blade nearest to you has a slight bend to the right! As I found on the trial this has no effect on performance, but.......



Friday, 8 September 2017

Finishing the paddle

Out of sequence
The last post ended with a photograph of the filler setting in the recess at the paddle tip, and this post as promised begins with the result:
What I failed to add at that time was that the filler was added when the paddle had been fully planed to shape through a whole series of secondary bevels which were not shown.
The tip was left a week to cure thoroughly before I began sanding with 80 grit paper, anything less brings me out in an epoxy rash from the still active dust from the tips:
Then through 120 grit the paddle was finished on something like 300:
Two overlapping layers of 6 oz glass cloth were cut for each side of each tip of the paddle, so that eight pieces were cut in all.
Which in place looked like this:
What is not clear is how the glass fabric fully covered the filler at the ends, most of which will remain in place to give very strong ends which should stand up to alot of abuse.
Then the filler coat was added:
And the excess trimmed etc
Then after standing a week and alot of sanding and polishing, then oiling with Deks Oljie the paddle was complete. Test paddle in next post.


Sunday, 3 September 2017

The may be last paddle

To recap
Apologies for the lack of posts. The paddle is now finished but I will start where I left off:
This picture shows just how much wood had been removed at quite an early part of the process. More was taken away when the outline was cut on the bandsaw.
The shape was traced round a cheap 3mm ply template cut to the shape of the paddle. Once you have drawn a few, you can generally adapt what you have without making a new one.
The actual curved shape of the paddle is carved accurately by first of all planing to chine lines drawn on the paddle. The edges are shown first:
Then the faces of the blades:
I normally use Chuck Holst's chine lines which are accessible on the Qajaq website; however as I wanted this paddle to pull well at the catch I modified them to give a flat area at the tips. Before planing to the lines I cut the recesses to take reinforced epoxy filler at the tips:
It was finished off with a Japanese saw rasp which works really well - you can get them from Axminster. The next pic shows the smoothing plane with which I started sitting on the blade face. I was about to plane across the corner nearest to the two nearest lines to that corner:
To produce a new angled face that can just be made out with difficulty:
I had to remember to take the lines round the tips. The only way I have been able to do this has been
by eye. After beginning the taper at the tip of the paddle I realized that I would need a bit more "V" near  the tip, so I modified the chine lines accordingly. Incidentally this was the first time I used curved lines.
Which gave a shape like this:
As the epoxy at the ends would have to be shaped just like the rest of the paddle, the recesses were then filled:
This photo was taken before the epoxy had set. You can see the backing piece of scrap paddle holding up the masking tape. I will show how it set, and then the rest of the shaping progressed in the next post.