You Do Need power plug adapter while traveling from Madeira to Gambia.

Here is Why You Need An Adapter

The outlet and plug type used in Gambia is G and in Madeira are C and F. This is how they look like.

Madeira

In Madeira, outlets of type C and F are in use.

Type C

Type F

Gambia

In Gambia, outlets of type G are in use.

Type G