[CA] [CA11] Depthsounders and orcas

[Teranodon]

Like many Puget Sound sailors, I am concerned about the declining population of resident orca whales. Recently, the Governor's Task Force identified sound interference from ships, ferries and boats as the second most important cause of the decline. Among the sources of noise are recreational depthsounders that emit acoustic waves in the 50kHz range. I have a P7 Shorty transponder on my sailboat, but I do not see any information in the manual (or the website) about the frequency that it transmits. Could Raymarine please provide this information for ALL transponder models? It would be simple to rig up a switch so as to de-power the instrument when the information is not needed - which, frankly, is most of the time.