Thanks Bill for your reply. Today I pulled the transducer and it is the 6 paddle model. I purchased some water-based antifouling paint and hopefully that will help with reliability. I turned on the ST50 and manually spun the wheel and noticed that even though I spin the wheel at a relativly fast, even rate the display increments by about .2 knots changing every second or 2 until it reaches the actual speed of the wheel. If I stop the wheel the display counts down in increments about the same size until it reaches 0. It takes perhaps 15-20 seconds or more before the display reads 0. (by the way the ST50 is not set to the average speed display screen) Is this normal? why the delay? I would guess that the unit averages reading out over time and this is why this is happening. It seems that the response is very slow though. Is it the transducer or the ST50 that is responsible for this delay? Thanks again for all your help, it is great to have you here as a resource! Matt