wrg49 said:
the transducer is on a swivel... so I guess it could swing aft. Is it supposed to be static ?
It should be tight. Lowrance ducers have a bolt that runs through the bracket and the mounting area of the ducer. Depending on how old it is... some have rubber friction washers, (spacers) and some have detents, or teeth built in that hold it in position. In either case, it should be tight enough that a decent amount of force is required to "kick" it up.
Make sure the bottom surface of the ducer is paralell with the running surface of the hull, and slightly, (about 1/8"+) below the bottom of the hull, when you tighten it up. See below.
The height shouldn't have changed, just the angle... but you never know. And if it did, you'll need to loosen the bracket mounting screws on the transom. Remove one at a time completely and re-seal with 3M 4200, 5200, Life seal, etc. You might want to replace the screws with new ones while your at it.
Imo, the newer, smaller Lowrance ducers don't have a lot of "meat" on the mounting area. They crack and break pretty easy. On the plus side... they hold a signal at high speed very well.