The best replacement for sounder is more sound.

The best alternatives to sounder are rated as following:
★★★★★  more sound
★★★★  fishfinder
★  imager
★  chartplotter
★  fish finder

Your alternative for sounder is not listed? Suggest!
Speaking about sounder, one probably shouldn't forget about strobe.

Other search terms related to sounder and their ratings are:
★★★★★ strobe
★★★★★ beacon
★★★★ flasher
chart plotter
You have in mind a companion for sounder and it is not yet here? Propose!



Google Trends

Scale is based on the average worldwide traffic of sounder in all years. Click on graph for more.
sounder
more sound
fishfinder