We have a 798ci HD Si with a standard transom mount transducer on a 5.8m Fibregalss boat which we use for fishing in open waters.
We have had no end of trouble with the transducer flipping up at any speeds above 35mph. We have tried replacing the bracket, adding some adhesive between the braket and the transducer to assist to hold it in place and in desparation even tried adding the screw to lock the transducer in the down position but this only resulted in the bracket breaking. Top speed of the vessel is approx 66 kph (42mph).
The installation of the transducer is as per the instructions - it is installed on the RHS of the transom (looking from the back) with the centre line (height wise) of the left hand edge of the transducer lining up with the bottom edge of the transom. The angle of the transom is approx 30deg so this means the centre line of the right hand edge of the transducer is approximately 40-50 mm (1.5 - 2 inches) below the bottom edge of the transom.
Does our installation sound correct?
Would you expect the transducer to flip up at 40mph?
Can you provide any suggestions as to a rememdy? I could obviously lift it up but I am concerned that this will increase turbulence and therefore performance at speed.