Re: New Transducer, old equipment
First off - the Raymarine ST40 is Bidata (Speed/Depth); the ST60 is a Tridata (Speed/Depth/Temp). Which have you??
If it's the ST60, it already has an offshore depth alarm function - you only need to set it up. You'll find the newer stuff has a lot more functions in it than the old, hence you're better advised to sell the Datamarine unit on Ebay and go sailing..
"Honestly, I don't know why seamen persist in getting wrecked in some of the outlandish places they do, when they can do it in a nice place like Fiji." -- John Caldwell, "Desperate Voyage"