Saturday, November 29, 2014

Aluminum Pipe Quadmaran

I am thinking of a prototype floating house that could be large and still not too expensive.  You can buy huge corregated aluminum pipes for about 1.66 times the cost of aluminum.

They come in sections that quickly bolt together.  So it is easy to ship and only takes a few days to put together.  It comes up to 1/4 inch thick, so it can be very strong.   It is called structural aluminum plate.

There are also aluminum beams that you can put around the circumference and also along the inside along the length of it.   So you can make it very strong and also strong in particular parts.

My idea is to use make a quadmaran out of this by attaching 4 floats and then covering the top with solar panels.   A picture of a model is below. 

The floats could be attached with 4 aluminum truss sections between each float and the main body.   Two spaced well apart up high and two spaced apart down low.  All 4 coming next to each other above the float and a 90 degree turn to 4 more trusses that go down into the float.   The ends may have to be cut and welded but it would not be too much welding.

The float would have the aluminum trusses for strength and then foam and a covering of styrospray and/or fiberglass.

This could be very cheap and very fast to build.   You could end up with a living space much larger than any boat in this price range.  Solar and electric would make it cheap to operate.  The quadmaran design makes it very comfortable and stable, even when going slow.

The connection points to make a train of these would have to be strong enough too.   One idea is to have a big beam running along the floor and sticking out at both ends.  Another is to have some beams come to a point in front and behind, like a nose and tail on the pipe.   Engineering details need to be worked out but I don't think it will be a problem.

In a normal house you spend roughly as much on the land as on the house.   Here you would have this as the equivalent of the land cost and then the house would be built in/on this.   But the end result could be comparable to a significant slice of houses in the USA.    There will be plenty of people who could sell their house and buy one of these.   There should be a good market.

I am going to double check the structural engineering and if this still looks good then I think I will try crowd funding with indiegogo or kickstarter.   If you donate $100 you get to ride on it for  a day.  If you donate $1000 you get the whole thing for a day.   But if anyone wants to start donating early, I happily accept paypal, bitcoin, credit card, Western Union, cash, check, gold, silver, or wire transfer.   

Quadmaran Train With 3 Models

I tested 3 models in train formation with a better joint between them.  The first with 3 floats rolls much more so I like the quadmaran design better.

 The joint is very simple.   On the back of one model is a piece of wood with a screw head sticking out.   This can be thought of as a trailer hitch except that it is aimed back instead of up.   The front of the other boat has a piece of wood with a small hole drilled in big enough for the screw head to fit into.  Then rubber bands are connected from the posts on the sides of the models to pull them together (keeping the hitch connected) and also keeping the models lined up straight, but with plenty of flexibility.

The little sandbags are to simulate the weight of the lead batteries that would be above each float in a full sized solar powered version.

On each side there are 2 rubber bands chained together.   They are stretched to about 18 inches.  At rest they are 8 inches.  I measured 0.64 lbs pull when stretching one to 18 inches.   I also measured 1.12 lbs pull at 28 inches.   Close to Hooke's law.   This model is 1:16 scale, so full sized would be 16 times in each of 3 directions, or 4,096 times the displacement or mass.   So if the rubber bands here are 0.64 lbs pull, in full scale it would be 0.64*4096=2,621 lbs.   This is small enough that it could be done with a hand winch and a stretchy rope.

I would like to point out that all natural waves are used in my wave tank.  This keeps costs down.   Pretty sure my wave tank has the best view of any wave tank used for testing experimental boat models.  :-)

Blow is a video.  Be sure to notice how the boat in the upper right is tipping as much or more than my tiny lightweight models are.  If these models were scaled up 16 times in each direction, so 4096 times heavier, they would hardly move in these waves.

And the next is really very similar so only the most dedicated need watch both:

And a shot of two of my boys:

Sunday, November 2, 2014

Quadmaran Train

My mission is to building solar powered boats that a family could live on and travel around in.  I want something very simple, reasonable cost, reliable, and easy to operate.   Not in a hurry to get someplace, so willing to trade off speed for stability and safety.

Amoni (my 7 year old) and I built a couple models.   We glued together 3 or 4 layers of 2 inch thick styrofoam with Gorilla Glue. 

Then carved this into the shape we wanted with hot wire.

 Then sanded.  Then pained on StyroSpray 1000 which gives it a nice tough finish.  Used a 1/8th inch plywood in the center of the floats and a piece glued under corners with metal brackets connecting these together.  I really like making models this way.

Ethan (now a teenager at 13) and I tested these models.

These models are 4 feet long and 2 feet wide.   They are 1:16 scale, so full sized would be 32 feet by 64 feet.   Loaded this model is about 10 lbs, so full scale loaded would be about 16*16*16*10 = 40,960 lbs.   You could clearly do other sizes.

We are testing where the biggest waves are about 1 foot.  At 1:16 scale that means we are simulating 16 foot waves.   In the Caribbean we only see waves like that during hurricanes.   Normal waves seems more like 3 to 8 foot.

The video needs to be slowed down by the square root of the scaling factor to show you what it would look like at full scale.  I think my video is slowed by a factor of 4, which is correct for a factor of 16 scaling.

I would really like to be able to connect several of these together to make a train in the water.  It would let you travel in larger groups.  You would only need one captain at a time.  You could trade things between the boats.  Attaching the boats together will also make them more stable.   And boats following behind will go over a bit smoother water as they are in the wake of the boat in front of them.

The video below is looking at how these two different designs are moving relative to each other in hurricane conditions.   At least at first we probably want to connect in harbors or at least in much calmer weather.

Note also that the 3 float version on the right rolls much more than the 4 float version on the left.  I like the 4 float version much better.

The quadmaran has a very smooth ride for waves this big.   In small waves it will be much more stable.  The shape of the floats (two sections of a sphere glued together) makes the waves just go around it and not splash.  This boat will not get spray on it like most.

When the models are connected together rubber bands on the sides keep them lined up straight in video below.   This video was not from my slow motion camera but just slowed down for scaling effect, so it is not so smooth.   In the full scale there would be bother computer control to keep them lined up and some stretchy rope as backup.  Because they are much more stable than a normal boat I think connecting them together will be possible.

In the full scale version the weight of the batteries would be placed in the corners, making it a bit more stable than the model is.   Also, the part connecting the center to the floats would probably be open to minimize wind resistance.

The hope is that a normal boat is affordable by the upper middle class American.   If someone had more money they could get more than one and link them up for more space.

If you have a group of boats chained together it would be possible to split up and have some visit an island while some stayed in international waters.  This way weapons could be kept in international waters.

Next I would like to build models at half scale using aluminum truss sections.   Some of the truss sections would be inside the floats, with foam pored in a mold around them and then styrospray and fiberglass/apoxy on the outside.  First I would build one and if that works then build a second to test connecting together.  These would be plenty big enough to day cruise around on.  Could put on the solar and electric.

Assuming the half scale tests work out well, the finals step would be to build a full scale with professional aluminum boat designers and builders.

Friday, April 18, 2014

Quadmaran Testing

We took the model into bigger waves.   These were at least 15 inches which is like 15 feet.  For the Caribbean this is storm or hurricane waves.    We forgot to put sand in so it is riding higher than optimal.

It did well but there were some times when a string went a bit slack.   I don't like this because a slack string would let two parts get some momentum going away from each other and then jerk on the string.   So I have been looking at other ways to do the strings.

Next we tried a string between front floats and also between back floats and strings from float to the opposite bottom end of the box.   This works rather well really.

Next we tried connecting the two front legs together and two back legs together and attaching them so they can rotate relative to the box.  Also put the 4 side strings all to a central point under the center of the box.   This did not work so well as the box swung side to side.

As it swung the two legs on one side would come closer together and go further apart.   So one idea is to have two more strings connecting the floats on the same side.

Thursday, March 13, 2014

Quadmaran model build

My quadmaran idea is that with 4 legs on a 40 foot container and 4 floats we could have a stable platform.  With just the right shape and size floats they and the legs could fit inside the container.  So the whole thing could be shipped as one container and then put together.   With the right shape floats they can have a soft motion in the waves.  With the wide stance, like 40 feet wide and 70 feet long, it would not tip too much or too fast.   Could be very comfortable even when moving at slow solar power type speeds.

Found a 16 inch styrofoam ball on Amazon.

We put the ball in a trash bag on top of some cement in a short bucket to make a mold.
 We were not that happy with the mold.
 Putting the ball on a bucket and using a hot wire we cut off 6 sections, leaving a cube.
 What is left is kind of like a big die.

Showing how 4 floats could be fit inside.  This box is 40 inches long, so we are modeling at 1:12 scale.

And 8 by 9 foot container (higher type) has about 11 foot diagonal.
 We had 6 nice halfs of floats, which makes 3 floats, but we needed another.  Also wanted to test out way to make the right shape for larger models.  Maybe half scale or full scale.  So edges of hotwire are tied to point on the side of the bucket and we can make 8 inch radius curves like on the 16 inch diameter ball.   By rotating the styrofoam and cutting many times we can make a reasonable approximation to the section of a sphere.
 Something sticking up in the middle so we can rotate foam about it.
 Discarded foam from first cuts.

Cut ends of legs so they fit over sides of box.  Then drilled holes through legs and box.  Then quicktie to hold together.

Box and legs with foam floats in general area to get idea of where we are headed.
 I used sun hardening resin for the fiberglass.  So I set things up the night before and got up a half hour before the sun.  Note how nice and smooth the floats were before the resin.

 The resin has eaten out big pieces of the foam.
 We tried to patch up foam with spray foam.  And painted things.
 It floats!  Put in sand to weigh it down so floats were about halfway in the water.

It starts out high in the water so I have my 4 year old put sand inside to weigh it down.

Took a bunch of sand but then it is down in the water more.

You can get an idea how much sand in this video.

You could push sideways on a float and the strings did not go slack, the model just moved sideways.

If you slow a video down by the square root of the scaling factor it shows you what waves would act like in the full scale version.   So these videos are slowed down.