David, I replaced my old electronics on my M23 with Navman gear and used the same transducer and bulkhead holes. The hardest part was getting the old transducer mushrooms out of the hull. Bones ____________________________________________________________ Click here to find the perfect picture with our powerful photo search features. http://thirdpartyoffers.juno.com/TGL2141/fc/BLSrjpTEuJCrPeTS2BUGMFHMRYBU2ApD...