I just updated the audio equipment in my 240 SD. I checked with the local Sea Ray dealer on removing the access panel for the dashboard gauges, there are 3 to 4 SS screws that hold the panel in the helm compartment. The screws might be buried in the lining cover, as were mine. Once the panel is removed you will find an aluminum mounting bracket that is easily removed by backing out the bolt nuts. Once bracket is removed the unit will pull out from dashboard. FYI I replaced old unit with Clarion MW1 purchased from Crutchfield, and Clarion M505 head unit from West Marine, it sounds awesome. Good luck.
