Please read the following table in Markdown format and then answer the question according to the table. Table cells in one row are seperated by '|', and different rows are seperated by '
'.

Table:
| Vessel | Built | Max Speed | Length | Breadth | Flag | Propulsion |
| --- | --- | --- | --- | --- | --- | --- |
| Gallion | 2010.0 | 30 knots | 20 m | 6.5 m | United Kingdom | Prop |
| Gardian 1 | 2010.0 | 30 knots | 20 m | 6.5 m | United Kingdom | Prop |
| Gardian 2 | 2010.0 | 30 knots | 20 m | 6.5 m | United Kingdom | Prop |
| Gardian 7 | 2010.0 | 30 knots | 20 m | 6.5 m | United Kingdom | Prop |
| Gardian 9 | 2010.0 | 30 knots | 20 m | 6.5 m | United Kingdom | Prop |
| Marianarray | 2011.0 | 26 knots | 17 m | 6 m | United Kingdom | Jet |
| Smeaton Array | 2011.0 | 30 knots | 20 m | 6 m | United Kingdom | Controllable pitch propeller |
Question:
What is the length when the propulsion is controllable pitch propeller?
Answer:
20 m