User:Vincecate/WaterWalker2
Building a 1:5 scale model/prototype like the WaterWalker model that is big enough for 2 people to take a kite powered ride along the South side of Anguilla. The legs will be 20 feet long. I have done several seastead models but this will be the first large enough to play on.
Got these 3 barrels for $20 each from the concrete plant. Now planning on using 4.
This 3" by 3" square tube is 20 feet long and cost me $53. Tropical island prices include shipping and duty, so are usually nearly twice mainland prices. I just got one so far to make sure I can work with the ends and that it is strong enough.
Testing 20 foot steel box-beam (square tubing) with 250 lbs on it.
Testing 16 foot 4x4 with nearly 300 lbs on it. The extra weight came on of its own accord.
Contents
Rope
I ordered some 3/4 Nylon rope which should be here mid December.
Costs
- Rope - $108.59 - need more with 4 leg design now
- 4 Barrels - $80
- Beams - $212 - 4 steel beams at $53 each
- Hardware - $72 - hinges, nuts, bolts
Weights
- Barrels 20 lbs
- 3" square tube 20 feet long - 48 lbs
- 4x4 at 16 feet long - 60 lbs
- 4x4 at 20 feet long - 75 lbs
Flotation
They are 54 gallons which is 432 lbs in fresh water and a bit more in salt water. The plastic underwater should float so only about half of the 20 lbs of the barrel really counts, or 10 lbs. The ropes holding the base in shape may be underwater or above water, not sure yet. Don't know the weight yet, but probably small and if underwater it should nearly float.
- Total flotation 1728 lbs
- Using half each 864 lbs
- Weight of beams 300 lbs (if 20 foot 4x4s but really a bit less as displaces some water)
- Available for people and other 564 lbs
Wood beams weigh more, but the weight of the part that is underwater does not count, and will actually give some net buoyancy. So wood could work about as well really. It might be possible to close off the end of the steel tube so no water could enter and it would provide some buoyancy, but I don't see it. If we had an aluminum box beam that was thick enough to weld to we could close off the end and make something to attach to at the same time. A 6 inch square aluminum box beam would be great.
Aluminum is a better choice for a production model but it costs much more so I am not using it for this prototype.
Sponsors
After this has been built, tested in the ocean, and documented on the web, these sponsors have pledged these amounts:
- Joep - $300
- Jesrad - $200
Maiden Voyage Route
Plan is to do 2.5 miles route that is never far from land. Will go into the water at one beach and then get out of the water at another beach. Will have a person in Hobie Outback along with model. The kayak may pull the model a bit south at the start if the kite has any trouble going south enough to clear land 1/2 mile from start.
If we can average 1/2 MPH then it would be about 5 hours to make the 2.5 miles. At 1:5 scale this is simulating a 12.5 mile trip at 1.12 MPH.
Possible Things to work on next for this project
- Measure force/speed for barrel in pool - barrel half full of water - both on side and upright
- Measure force/speed for 4x4 section in pool
- Put piece of 4x4 into ends of box beam
- Figure out how 3/4 beams will join together at the top
- Figure out if I want to suspend a kayak as the seating and backup or other type of seating
- Measure thrust lbs from Hobie Outback
- Measure force from kite
- Make attachment to barrels and test by filling barrel with water and lifting by rope
- Top connection can be by elastic cord and weight of people pulling 3/4 beams together
- Model 4 leg WaterWalker to see how reasonable that would be - diagonal ropes in air or full tensegrity?
- I have pulled my 2500 lb boat (really 3600 lbs with water ballast) with my kayak, this at 1/10th the weight but less hydrodynamic is probably similar really. So I am sure I can move it with a kite or kayak. But question is can I do an 8 mile trip in less than 8 hours? I want to be sure so that I don't end up having to land at some less than ideal place or staying out till dark.
