A few kind words, if I may, Potatoe?
Sizing a PVC fitting to act as a stabilizer for the transducer is best found with measurements until a close fit is discovered.
Then saw enough away to allow the cable to fit through then slide the xducer into place.
Use an o-ring, rubber-band or non-damaging sticky substance for retention.
Several feet of PVC pipe with a similar saw cut several inches up the pipe for the cable to come outside then, slide into that fitting will maintain stability in use. Caution: No cement~ just use a cotter pin and only drill the hole with the ducer and cable removed.
Support this with a small rope through holes in the upper portion of the PVC extension, thus not putting the added weight of the PVC on the cable/xducer area, tying off to the dock/pier or something that floats.
Questions welcomed.
( I shouldn't say, I avoided buyers remorse by purchasing, first, a chart sonar with skimmer xducer (with a bolt hole). And it also has those whirly multicolored flashing lights that make me dizzy and never get used. )