My boat assignement.

[Andreas]

Hi,

I have no experience with boatdesign so i tough i could get help from guy's/girls who do know on this forum.
I have to design a boat that autonomously goes from point A to point B (see pics), on the way to point B it has to pick up a playmobile doll, wich is standing on a pontoon, and place it at point B. (all by itself) The boat itself has to stay within the volume of (150mmx150mmx200mm).
My only energysource that i can use is this (i'm allowed to use max 4 for propulsion and pick-up mech), it works with a spiral spring inside:


This is the top view of the watertank:

Overview of the tank:


I was just wondering if you guy's could give me some advice about the best way to get my boat going, things i have to pay attention to,...etc

Thanks!
Grts

[daiquiri]

And I thought that I had already seen every possible odd floating stuff on this site...

[messabout]

The boat is not the problem. You can use something as simple as a box like object. The problem is to design mechanisms suitable for the pick up and deposit of the doll as well as steering the boat and detecting the locations. Your rules are not entirely clear but as I read the post, it would seem that you can not use radio control and the only allowable energy source is to be a spring. The spring can drive the boat sucessfully but the rest of the requirements will be a challenge. Tell us a little more about the details of the project.

As for the boat, you must first make a reasonable estimate of the weight of the boat itself and the mechanism that will drive the boat and the weight of the doll. A closed geometric figure with the dimensions that you have given, could displace about 4.5 Kg. of water. If the total weight of the boat, mechanisms, and doll are half that amount or less then the flotation potential is adequate.

[daiquiri]

This is funny, I like it.
Any dimension limits for the boat? Is any hull type allowed?

[Luckless]

That is actually a really interesting (and useless) challenge.

My first thoughts would be to design a small craft that is propelled by one or two of the springs and travels in an arc from A to B and barely touches the "C" point for pick up. Use a spring loaded claw of some kind to grab the payload, and then a trigger to throw the payload onto dock B when the boat runs into it.

[daiquiri]

Originally Posted by Luckless

My first thoughts would be to design a small craft that is propelled by one or two of the springs and travels in an arc from A to B and barely touches the "C" point for pick up. Use a spring loaded claw of some kind to grab the payload, and then a trigger to throw the payload onto dock B when the boat runs into it.

We have had very similar thoughts.

I had asked about hull type limitations because a cat would be more suitable to this task - it will not heel after grabbing the doll form the pontoon (but how heavy is that doll anyways?).
Second, I had asked about dimension limits because I like to cheat. If there are no limits for boat's length, then you can technically make a boat with a hull length just a bit smaller than the distance between A and B. Then it can travel in a very short straight line from A to B, without the complications relative to the calculation of the arc or parabolic trajectory. In that case, one spring can be used for propulsion, and all the rest to control a mobile "crane" (or "claw", as Luckless called it) movement, which will have a simple semi-circular path from A to B...

[Andreas]

Hi,

Thanks for the fast reply's.
I'll try to translate the whole assignement.
Here goes:
_The energy source: Skipas holder (see pic) with a cord approx. 80cm long.
Use max 4 for propulsion and stearing of the mechanism.
example of the doll (mine weighs approx. 13gr):
You can put the doll in any position possible.


Design a boat that is able to go autonomously from point A to B, picking up a passenger on the pontoon and putting him down at point B.
You can choose where you put your doll on the pontoon, after putting the doll down at point B it cannot have any contact with the boat anymore.

At the start: _the boat has to foat (logically)
_The propulsionmech. has to be unlocked by hand and after that there is no more intervention.

Startvolume: 200x150x150
after the unlocking of the mech. the volume is allowed to change, but at the end everything has to be back in the volume.
It's not allowed to leave parts behind, everything has to stay together.

If something is not clear please tell me.
Grts Andreas

@messabout: Radiocontrole is not allowed unfortunatly.

@daiquiri: Any hull type is allowed as long as it stays within the volume of 200x150x150.

[daiquiri]

In that case, it can work... take a look at my previous post.
But keep in mind that it is a solution which stretches the rules to the limits. Is it a cheating? I don't know.

[rasorinc]

Can you use magnets?

[Andreas]

Hi,

I just realised i forgot to ad the dimensions of the tank: 1m by 2m.
@daiquiri: That was one of my first idea's going straight ahead and picking the doll up with a swinging arm, but the dimension limitations don't allow this solution...
If you have the stay within that volume you should need a kind of arm that stretches and returns into that volume+picking the doll up with this solutions would cause unstability i think..
btw: the volume dimensions are 200mmx150mmx150mm, the boat on your drawing would be longer than 1000mm, but you couldn't know because i forgot the tank dimensions sorry!

@rasorinc: Magnets are allowed i think, it doesn't say in the assignement that they aren't

Thanks!!
Grts