June 2013

On Sunday June 23rd my friend Kevin and I took the Chameleon to Lake William for it's first trial since the gearbox failure of last summer. There have been a few changes since then.......

I had the original gearbox switched from 2:1 to 1:1 because I was concerned about reliability. Well this boat was designed to be used with one or two riders so when it came time to make up the drive train for the second rider I chose to buy two new gear boxes and went with 5/8 shafts and 1:1 ratio. I will use the other box for the single hull version. Each drive system is completely independent of the other and installed on a 2 x 2 tube with the gearbox on the inboard side of the tube. From there a 10 foot aluminum shaft goes back to an airplane prop with the only support being a 1/16 wire to a small steady bearing. (which could and will be smaller at some point) The wire is just to stop the shaft and prop dragging on the bottom when pedaling stops. It is also a way to lift the prop free of the water when not pedaling and to clear weeds, lobster pot lines etc. The shafts are both turning clockwise when viewed from the stern so that they tend to move in the same direction when getting on and off the power. The  props are also designed to turn in one direction only. Plus, the shafts are different lengths to reduce the chances of them hitting each other.
There is a spring loaded idler wheel on the chain which has a limiting bar so that the drive train can be pedalled in reverse. One prop is a 16 x 14 and the other is 16 x 12 right now.

The frame has been lengthened one foot and an extra set of anchor brackets has been added to both hulls. The two piece deck is cedar and is now only as wide as the frame without the extensions. I had grand plans about having enough deck space for a carnival, hot tub, and float plane but........things are heavy enough as it is!
I made two seats from aluminum tubing and covered them with red mesh. The blue is just temporary!!!

The rudders are raised and lowered by the levers on both sides of the deck and I can reach them both if I am using the boat on my own and sitting in the middle. The steering control uses wire in a plastic jacket and is set up so that it can be moved depending on the number of people pedaling. The left rudder is always connected and the right one is only to be hooked up for sailing or rough water.

So on Sunday morning the boat was fully assembled on the shore and carried to the water, clearly this thing has been eating well over the winter because it is a LOT heavier than the ideal...........Anyway, we paddled away from shore and dropped the props in while the boat was drifting, I started to pedal and it felt like the boat felt like something was dragging on the bottom......I looked back and realized the prop was turning the wrong way and we were in reverse!!! At some point I got the gearboxes on the wrong side doh!! An easy switch and off we went again, this time it worked well. It was quickly evident that we were going to have to come up with a way to increase the rpm of the prop because the boat was certainly not at full speed when we were pedaling as fast as possible. But everything worked okay and the props did not hit even during hard turns.

Things needing attention,

I have made two 90 tooth props to replace the 52s on there now. Much cheaper than replacing gearboxes etc. Also made two fixtures to go in the ends of the frame extensions with 12 inch wheels on them so the whole boat will be easier to manage, plus I can move it myself.

The method of raising and lowering the rudder works well but the steering is unsatisfactory. Too many lines and shackles etc and the steering effort is too high. I can do things to make it a bit more efficient but I am thinking about doing it using hydraulics. Single action cylinders could be built quite easily, double acting are more work but certainly possible. Plastic cylinders, stainless rods, plastic lines.....More complication but a fun little side project....
At  some point the seat mounting brackets will have to be made easier to adjust but will do for now.

Tomorrow I will get at least one mega sprocket installed ( don't have another crank with the appropriate offset at the moment ) and now I am just waiting for a break in the rain to try it again!

Hi

Going to be a quiet winter for the boat. I am bulding two seats from aluminum tubing and open mesh. The frames are complete and painted, the covers are cut and sewn, now I just need to make one more fibreglass seat platform and I can put them together. I'm going to make a few changes to the frame as well to streamline things a bit.
I had the whole boat assembled in the driveway and was running control lines through plastic housing to main control centre between the seats (or beside the seat if I am going solo). I made blocks to attach to the deck that were the correct size for the tubing, and I used tie wraps on either side of the block to stop the tube from sliding under load. This worked when things were dry but slipped when they got wet.  Steering was easy and moved smoothly but the force required to raise and lower the rudder was much higher than I expected. About this time I decided to pull the plug for the year........Get back at it in March I guess!

There has been a pause in the testing of the new cat because of a gearbox failure. I am happy to report that the box was returned Friday and the ratio has been changed from 1:2 to 1:1. This gearing is less desirable but should be much more robust. The diameter of the output shaft is only about 7 mm and I think that while this is may be fine for a lighter craft with less drag, it isn't enough for this application. They were great to deal with and I may buy another drive from them shortly.
In the mean time I added some graphics to the hulls and changed the mounting methods for the drive line tubes, built a couple cedar decks to cover both single user and double user configurations.
I am going to be away for a few weeks so nothing will happen on this front for a while. First results were very encouraging so I am looking forward to the evolution of this craft!

 

Some not-so-good quality video

The on-board videos was taken with 430 pounds of man and spruce and I really don't know what the speed was. We were not trying to go fast but just keep up a decent speed. Cadence was well below ideal.

Hi,
I've had 3 test sessions so far and we are getting the bugs out slowly. First, the hulls are dry inside, and they seems to move easily through the water. On Saturday Kevin and I were both on the boat and we took turns pedaling while the other tended to some issue. Then while I was pedaling Kevin took pictures and video of the wake at various speeds. Unfortunately I couldn't seem to get the GPS on my phone to cooperate so we don't know the speed although folks along the shore were complaining that the wake was making it unsafe to swim......
We tried several props and it does make a big difference how much the boat and cargo weigh. The 16x14 APC pattern prop was just too aggressive with two people on board. The boat seemed to move right along but I could not reach a cadence I liked and still keep that up for an hour with two people on board. Now if there were two drive units we would be going faster and that might have worked. In the end we were using a 16x12 prop that had been previously cut down to about 13 inches. It was a bit light for a single rider but good for two. I bought a few larger props but I won't use them unless I back off on the gearing. At some point I would like to tow the boat through the water and see what the drag is at different speeds.

I dropped the frame down about 5 inches and could go a bit lower but I don't think I will. It's great for flat water but too low for white caps I expect. I will keep the original frame extensions and make 4 more so that I can switch if I have to.

On Sunday Jane and I went back to the lake and did a bit of a tour. The issue of dragging the prop prompted me to take another stab at supporting the shaft which seems to work quite well. Basically I changed the support so that the only restriction was to keep the prop tips from falling more than 6 inches below the surface. Other than that the shaft and prop came move where ever it likes. At the shore I got Jane to pedal while I held the boat and the drive shaft bowed out enough that the prop moves ahead almost a foot! But it seems to be okay at this.......... We went out around some islands and back with the only issue being that I forgot to tighten up one of the bolts on the rudder bar and the forward end came off so it bent the tie rod at the back to about 90 degrees. But we borrowed  a bolt from something else and wade it back fine.

Pictures to follow and maybe video if I figure out how to upload it.

First wet test

So.......first wet test on Saturday morning. Jane, myself and Kevin went to Cox Lake near Tantallon where we met Bill who had paddled over to help. We put the hulls and frame parts together without incident and then clamped on the boom with all the drive train, the seat, and the support tube that held the steady bearing bar for the prop shaft. We had the center of the main frame marked and positioned the assembly with the center of mass where we thought it should be. Right on the money, because when it was thrown in the water it was about 1 inch out of the water on the bow and stern. This was installed with duct tape, c-clamps, retchet straps etc!
I kept one rudder dry and installed a telescoping tent pole to the other with a ball style tie rod end. Since this was still not long enough we duct taped a paddle to the end of the handle.. Nothing but the best.....

The prop was an APC plastic model airplane prop ( 16 x 12) and I should have taken a picture of it before it went in the water. It is on the end of an 11 foot aluminum shaft, 3/8 in diameter, or just under 10mm.
52 tooth crank sprocket, to a 14 tooth sprocket on a 2:1 Miterpak right angle gear box.

The prop is installed on a stainless steel stub shaft which goes through a Delrin block. This is bolted to a 1.5 x .125 aluminum flat bar going up to the frame. This is what I wanted to use to set the maximum depth of the prop. All the joints used 1/4-20 bolts with self-locking nuts so they could all move without falling out.

The first thing I noticed was how easily the boat moved through the water. A very light effort with a canoe paddle would move it right allong. I started to pedal gingerly and everything worked great. However, when I used just slightly more effort I could hear the prop hitting so I went back to shore. Turns out that when pedalling, the bow in the shaft is very much exagerated and this effectively shortens the shaft which changes the angle on the aluminum flat bar. So we experimented with woving the hinge point forward but eventually ended up taking the guide off altogether. This worked great for about 10 minutes and while I was starting to push just a little, one blade snapped off the prop!! On examination we could see that the other blade was white and soft at the same location and it broke a few minutes later. by this time we were just using a loop of rope to lift the prop for shallow water. I really don't want the prop dragging on the bottom when I stop pedalling....

I think maybe the gearbox is just too far above the surface and the blades are working too hard to try and straighten shaft when pedalling. There was more flopping of the drive shaft than I expected but this could be due to not enough of the shaft in the water.

Over all I was extremely happy with the first outing and now will start the refinements!

Summer is getting close and I am not on the water yet, but getting closer.......

The woodwork on the hulls is almost done, and once I scrape some of the runs off the bottom it will be ready for paint. The tops need one more coat and they will be ready also. The holes are cut for the access ports but I will need to install them as the last step because I have to reach as far as I can (and a bit further) to place the nuts for the main frame mount on the inside. Can't reach far enough with the ring in place. I am going to paint the hulls white and add some graphics over that.

I had these frame mounts water jet cut from 2 x 2 x 1/4 alumium angle and they are bolted though the deck and the stringers (still don't know the right word for this) which is doubled for 12 inches at these points. Using four #10-24 SS screws per mount with 1/8 stainless steel backing plates and locking nuts on the inside.

I had planned to make the rudders myself but the equipment is not available at this time so I bought two rudder kits from Seaward Kayaks, very close to my home town on Vancouver Island. And, since I bought two they gave me a break on the price thank you very much!!! These are the larger model from the double kayaks. I will probably use just one 90% of the time but when the water gets rough I will be more concerned about handling than speed. Most of the time I will need very little turning input so I will only lower the one rudder as much as I need to. I have made two rudder mounts out of fibreglass and will drill the holes and mount them temporarily to check fit and alignment.

Nice boots...!

I have the frame  under way now. I ordered 3" x .120 wall aluminum square tube but they delivered
2 1/2 instead and then informed me that they couldn't get the other, don't believe but.....So I made the main frame out of that. Since the hulls will be at least 6 feet apart the frame would be pretty awkward to manage and transport in one piece. So I made the ends removable and built them from 2" x  .120   square tube. They will be pinned in place with 1/2" round aluminum pins, both to the main frame and to the frame mounts on the hull. I will use 80 duro rubber to take up the space between the frame and the ends. This will allow a small amount of movement without torquing the mounts too much. I hope.

For now the boat will be set up with one rider although all the drive line and seat components will be on one bar which can be moved or doubled at any time. This is shown with the seat off one of my home built recumbents. I had planned to use a lowracer seat but but found this to be more comfortable. I have lots of bike parts laying about so I am using a Tiagra triple crank and one sprocket on the Mitrpac 2:1 gearbox up front. And a front derailler. This will be a 3 speed machine at first anyway. One speed for cruising, one for going up the face of really big waves, and one for going down the back side....... Plus, if I make the spread between gearing smaller that a normal bike I can do more testing with less wrenching. I will use the derailler underneath and a chain tensioner up top. This will do two things, allow me to have some capacity to span gear ranges, but could also be calibrated to indicate torque. That way I will be able to read speed from a GPS, torque from this apparatus, and rpm from the input shaft on the gearbox. There will also be the capacity to lock the tensioner to allow reverse. I am going to use a long curved shaft but it will be supported close to the prop. I am going to use a thin aliminum or plastic blade down to an impregnated bushing for the shaft. A lever will raise the prop until it just clears the water so I can avoid rocks, beach pull ups, get it out of the way when using a kite or sail,  and clean off weeds, baby seals, and other stuff. So with 4 lines to control the rudders, 4 more to raise and lower, 1 more to raise the prop, 1 cable to the derailler, 1 to raise the beach umbrella, 1 to raise the pirate flag, and I plan to use a kite with more lines, and probably a sail with more lines...................if I used an electric trolling motor all this fuss would be eliminated........