Why need to change new DS-631/DS-660 regularly

DS-60's flush mounting type transducer (Model: DS-631 / DS-660 ) was designed under-water plug, we found the under-water plug would be worn out by sea water. Especially for VLCC, VLOC and others more than 50,000 GRT vessel, the transducer work underwater with high pressure ( mostly the draft more than 10 meters and pressure more than 1 bar).   Picture is the 5 years' transducer cable connector :

The GOLDEN FINGER was worn out: (Normal golden finger marked green, corrossion golden finger marked red)

We advise these vessel to change NEW transducer with cable during 5 yearly docking service. Otherwise, doppler log may work abnormally after 5 yearly docking service.