Sunday, May 17, 2015

New Amas, Akas, Rudder

The amas are more or less done. There were the usual problems with glassing over foam, e.g., "bubbles" near the edges where the cloth didn't stay flat due to the stiffness of the fibers in the direction perpendicular to the edge. Normally this is prevented by applying the cloth at a bias, or vacuum bagging, but with the curvature of the bow sections it would have been a problem getting that area smooth and flat without going to multiple cloth sections - and I don't have vacuum bagging equipment.

The cloth was applied to the amas upside down. By this I mean the tops of the amas were placed in the center of the cloth and the two edges of the cloth overlapped each other on the bottom and ended about halfway up the sides. This gives the bottoms extra thickness and strength for the inevitable bumps on the beach stones, logs, parking lots, etc.

For this project I used a different type of epoxy resin: Resin Research 2000CE and Resin Research 2100F hardener. According to the manufacturer this stuff has UV inhibitors built in, and according to the supplier this stuff is used by people who make surfboards, SUPs, etc., which are often glass on foam just like these floats. To get the yellow color I added System 3 yellow pigment.

There were no indications as to how much pigment was needed to obtain a relatively opaque color, but there are instructions that the pigment to resin ration should not exceed 10%, so I guessed. The end results are perhaps not quite as pretty, and some of the underlying colors from the foam are showing through, but they are functional.

For two of the amas I cut the receiver tubes to be the same width as the amas. This allows the amas to be carried side by side without worrying about the receiver tubes gouging each other. However, this also means that in order for the ball-pins I had on hand to fit properly I would need to have some of the resin and glass cut away with a Moto-tool. For the second set of amas I cut the receiver tubes an inch longer, with the extra length inboard.

I used a structural fillet (Silvertip EZ Fillet) to help secure the receiver tubes to the top of the amas, along with some strips of glass and epoxy. After sanding the edges and surfaces smooth with the orbital sander (I love the shop vac attachment for reducing dust!) a coat of non-structural fillet was applied to smooth the surfaces. Unfortunately, however, the fillet applied to one of the amas did not seem to have adequate hardener mixed in. The resulting thick, gooey stuff had to be sanded off.

A final coat of pigmented resin was applied to both amas after they were placed upside down on the workbench. This was to ensure that any drips would appear at the top where they could be sanded off without adversely affecting the smoothness of the surface that would be making the most contact with the water.

The previous amas had a single aka (each) for support. The new ones have two. This results in a much more secure mount. The rear akas use the same support on the hull as the old ones. The front akas use the seat handles.

At the Jetty Island Race the floats worked perfectly. There seemed to be a little less drag and the boat seemed to be able to balance a bit more easily with both floats more or less out of the water. The extra flotation was definitely noticeable.

Given that the weight of the new floats+akas is actually slightly less than the weight of the old floats+akas, I'm reasonably happy with the results.
There was an auction at the Washington Water Trails Association annual meeting and dinner a few weeks prior to the Jetty Island Race. One of the items at their silent auction was a one piece kayak seat back and inflatable seat cushion. It looked like it might work as a replacement for the closed cell foam pads that I had been duct taping to the hull for the past couple of years, and it was definitely worth a try consider the cost was under $20.

It came with straps and securing hooks intended for a sit on top kayak, but these appear to work pretty well when hooked to the water bottle cages on either side of the seat tower. I still have to add a foam pad to the seat back to get the thickness to match that of the back of my PFD, but this is definitely a nicer looking arrangement than before.

I added some friction tape to the deck in the cockpit area. That is what causes the black line in the above photo above the propeller shaft.

At the Lake Whatcom Race I tried out the platform pedals for a short time. They seemed to work.

So...the last thing to work on was the steering. After thinking about this off and on for a couple years I decided to make a kick-up rudder much like that used on many sea kayaks.

For this project I would use the same mounting T-nuts that secure the dipping rudder assembly. Given that I still had laying about the aluminum U-channel that was used for the original propeller support, it was already drilled to fit. All I had to do was cut off the cantilevered portion, weld it perpendicular to the horizontal portion, weld a couple of 1/8" aluminum tabs to it for a hinge support, and then cut some right angle pieces from an old aluminum computer cabinet for the rudder side of the hinge, weld some tabs to *that*, cut a rudder plate to size, and drill a bunch of holes. Whew!

In the photos the beige-white colored pieces are from the computer cabinet. The metal is about 3/32" thickness.

The rudder blade is about 15-3/4" long overall, and 4-1/4" wide. The raising arm extends another 3-3/4" sternward.

The bolts are 1/4" stainless, with Nylock nuts where appropriate and regular elsewhere.

I reused the steering cord from the dipping rudders to control this rudder, making a loop from the left rudder control arm, under the old left dipping rudder steering tube, through one of the plastic eyelets on the deck, under the rear aka support, around the right side of the seat back to the left side of the seat back, back under the rear aka support, through the other plastic eyelet, under the old right dipping rudder steering tube and finally reaching the right rudder control arm.

I did not reuse the 1/8" shock cord from the old dipping rudder to keep the kick-up rudder in the down position. Instead, I used some heftier (1/4") shock cord I bought at the same time for this purpose.

 A new cord was added to the mix, attached to the trailing arm on top of the rudder, threaded through an eye bolt at the top of the rudder assembly and strung along to the side of the seat. This cord is used to raise the rudder out of the water. A tiny carabiner tied to the cockpit end is used to hook onto a bolt on the crank assembly to secure the rudder in the up position.
 The weird colors on the rudder are due to either the original cabinet cover being used at one time for a spray paint booth (gold and silver), or from the welding process (black). I'll paint it properly when I'm satisfied with the results.

 At yesterday's Commencement Bay Race in Tacoma, WA, the rudder assembly was put to its first test. Just prior to launching I discovered the shock cord had become untied. Oops! A better knot was quickly applied and all was well.

My brain must not have been working quite right, however. See the black thing just behind the seat by the water bottle? It was a roll of duct tape I used to secure the safety rope and inadvertently left on the rear deck. Believe it or not it was still there when I took the boat from the water after the race.

Anyway, everything worked quite well. The rudder was far more effective in turning the boat than it had ever turned before, and with far less drag. Minor course corrections were easily made and with minimal loss of speed. Sprints with the rudder removed from the water with intermittent rudder drops into the water for course correction worked well, too.

While there was not much of a wind to work with, there appeared to be a bit less of an issue with weather cocking.

I think a slight improvement in steering can be had by cutting a new rudder that extends a little closer to the hull.

Speedwise it appears that the rudder adds only a little drag. Painting it with a smooth finish will probably help a bit as the rough paint finish certainly isn't helping water flow!


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