I was given a suction cup by my brother's father in law and decided to give it a go.
|Completed transducer bracket|
I wondered at first whether or not the cup would hold but it has never fallen off in 7 years.
This prevents horizontal movement of the bracket when under way.
The cup sticks to the bladder quite well. It is available from a number of suppliers. A quick Google search for "transducer suction cup" should show you where in your area.
You can see the hole better in the picture below. The bracket is made from aluminium.
|Support hole in bracket.|