PedalTheOcean.com

Wow - did I ever get a lot done over the last few days. Dare I say that I think WiTHiN is just about ready for her maiden voyage?

The first thing that I wanted to do was to fair-in the drive leg gear box. The amount of drag from that square, chunky box behind the prop is probably substantial. However, before permanently enclosing the gear box, I knew I had a bit of work to do on it. First off, I chopped off the large square steel tube that was used to mount the gear box to the drive leg struts. I cut half of it off to a much lower profile. Then to add some strength to the connection, I welded two nuts to the cog housing so that the gear box was now being held in place with 5 bolts from two angles.


Next was to re-build my little 11 tooth cog. The grub screw holding the gear onto the axle needed to be an Allen screw so that I could get access to it with a small, right angle alley key. this would allow me to pull the cog off the axle if I needed to, without having to first remove the entire gear box. So, I decided to build a brand new cog using this 1/2" collar with a Allen screw set screw built into it that i had picked up from the hardware store the other day. This fit perfectly over the axle, and I had a washer that I welded onto the collar and then welded a new 11 tooth gear onto that. Perfectly CENTERED. My old one was a wee bit wobbly because I couldn't get it to center. This one works much better.


Then, I made an access plate that is held on with one screw and siliconed around. I bolted it all together and siliconed all of the joints.


Then, to make my fairing, I made a card board box, suspended the drive leg in the middle of the box and poured two part expanding foam into the box. When the foam dried, I ripped off the cardboard and proceeded to sculpt out a nice tear drop shape.



After i was happy with my sculpture, I wrapped it in a few layers of fiberglass, then whetted it out with epoxy and wrapped in in stretch seal to cure. I sandwiched it between two flat plates and 75 pounds to make certain that the exact width was the same as the drive leg bay (or I wouldn't be able to get it in or out!).



After it curred, I coated it with Bondo and sanded smooth.



Since the gear box is water proof, and since I have sealed all of the joins, gaps, bolts, etc with silicon, AND covered the whole unit with foam, multiple layers of fiberglass, soaked in resin, then a Bondo otter coat, it 'should' be water proof.


The next thing I did was coat the rudder with micro and sand smooth.



Then I re-built parts of my steering mechanism. During the pool test I noticed that the threaded rod connected to my steering tube was flexing a bit and also rubbing against the side deck. I also noted that during a hard turn, my handle clamp would slip. So, I added a pin to the clamps on my steering handle and the clamp on the rudder steering tube in the back. I also replaced the threaded rod with a stainless steel tube.



The very last item on the list was to install my soft decking. I am using aircraft wing material called SuperFlite Light fabric - like Dacron. I bonded the fabric to the gunwales of the bow and stern compartments using contact cement. Then I used a hot air gun to shrink the material tight. It came out really sweet - like a drum!. I made a small test piece and poured water on it and it leaked like a sieve. Darn. So, I called my local composites shop, Industrial Paints and Plastics and asked what I could paint the Dacron fabric with. He said he has customers painting sail cloth and fabric wings with a water based marine polyurethane top coat, so I ordered some red and painted the decks.





Now I need to dust off my two way radios used for the 24 hour HPV record in Eureka, and my wicked powerful HID headlight that I used for the failed 24 hour record attempt in Alabama. The HID headlight will be necessary to see where I am going in the dark hours on the lake during the 24 hour HPB record attempt 4 weeks.

I think I'm in the lake on Sunday. If you are local, and want to come out, then email me for details.

Labels: boatbuilding

Well, I checked off pretty much the last major item on the ever-growing TODO list for WiTHiN today. I was supposed to be out on my bike all day today, but it snowed yesterday and rained all day today, so I postponed the ride for tomorrow and made further progress on WiTHiN today.

The only major item still left is the lake test - and this is the big one. I know WiTHiN floats and is fairly stable from the pool test. I also know that the drive, prop and steering works. What I do not yet know, and this is HUGELY important, is how fast WiTHiN is. If for some reason, our calculations are wrong about the hull shape and prop specs using my known rpm and power, then there is a possibility WiTHiN won't be efficient enough for a 24 hour distance record attempt. So far, everything has worked like it should, but I know from experience that you just can't assume things until they have been tested.

Again, the calculations that I really hope to verify this weekend at Glenmore Reservoir, are as follows:

RPM = 78 rpm (verified)
Power input = 149 watts (verified)
Weight = 122 kg (verified)
Drive efficiency = 95% (verified)
Prop efficiency = 84.7%
Speed = 10.2 kph

If I spend 24 hours at 150 watts, then my ending average including everything should be about 110 watts. 110 watts converts to 9 km/hr average speed, so I should be good for 216 km or so. The current HPB record as recognized by the human powered vehicle association is 168 km. The rules are here.
Now, if I really messed my prop up, and the hull drag is WAY higher than we estimated, then I would need to be no more than 12% slower (7 km/hr) to still travel 168 km.

I have a separate update coming detailing all of the progress on finishing WiTHiN that has been completed over the last week.

Labels: expedition