Wave Project‎ > ‎Design‎ > ‎

Anchor

Requirements

  1. Stable - The anchor must not fall over and trap the pulley
  2. Grip - maximum grip to the seabed without spending too much
  3. Disposable yet retrievable - Since it's not economical to service the anchors they must be designed to be disposable. No maintenance must be needed. However It must be possible to retrieve an anchor should it need to be moved and redeployed at a new location. It should not be a fixed fixture to the ocean bed.

Main Anchor Design

The simplest construction is to use cement blocks. A cleaver way to do this is to pour cement into a large can (ex. a coffee can). Make sure the pulley is attached before the cement dries. This will make a very simple dead weight anchor.
A pyramid shaped anchor might be better since it’ll allow the pulley to stay at upright.

Construction:
1) Create a cast for making the anchors
2) Put in the rope that will hold the pulley then pour the cement around it
3) Putting a few poles through the sides of the pyramid will help it stay upright better plus it will hook better to the sea bed
4) Once the anchor is dry, attach the pulley to the rope that is now secure to the anchor
5) Attach a static line to the anchor as well. This line will also be attached to the float in case the main lead breaks. It will also allow the anchor to be retrieved if needed. 

Lead Anchor Design

The goal of the lead anchor is to guide the cables back to shore. This is to stop them from tangling with the sea bed and to lessen friction as the cable is angled up to the generator.

Concept 1 
The first option is to use anchors like the main anchor to guide the cable back to shore.

Pros
  • This means that no extra construction is needed and the same anchors can be used 
  • They can be smaller since they won't have so much pull on them
Cons
  • They will suffer from the same problems as the main anchors in the sense that they will use pulleys. These may still tangle

Concept 2 
The second option is to use guide pipes. The idea is that if the cables are in pipe while being guided to shore they are less likely to get damaged and tangled.  Use a standard cement drain pipe. Cover the entrances with a grid. These grids guide the cables into the pipe and stop them from tangling as well as keeping things from the sea out. Ideally the guide holes should be rounded to lessen friction.  

Figure: Guide Pipe Overview 
Pros
  • The pipe itself will act as an anchor. They will be set in place on the sea bed.
  • No tangling cables with plant life etc.
  • No debris falling on the cables and getting them stuck
  • Pipes would be easy to procure   
Cons
  • This would cause added costs
  • How do you stop the pipes from rolling around?
  • How do you deploy the pipes? The cables should be inserted before the pipe is deployed
  • If the guide holes aren't constructed with care they will damage the cables
  • How do you replace a cable if the old one brakes?
Comments