(DG) Replacing early style masthead Wind transducer

[sailingriki]

I don't know why this thread was closed, there are plenty of questions for these old instruments!
I talked to a Raymarine rep and was told the R28170 would plug right in to my old Autohelm mast top base. But when I went to buy one at West Marine I read this:

will this item E22078, replace my original installation of a ST50+ masthead windvane and screw into the existing ST50+ mounting block (threads and electrical/data connection at the top of the mast head?
Asked by Dean the sourcer 2 years ago

Verified Reply - Customer Service

The part number for the ST50+ transducer is D168, but it hasn't been available for many years. There aren't any current wind transducer offerings that are compatible. You may we able to locate a used replacement. Otherwise you may need to consider replacing the instrument entirely.

I'd like to replace my mast top components but understand there is a problem with wind speed, some say adjustable some say not. I have old Autohelm square instrument so, I guess, not a 40 series?
What is the final word on this please?
Thank you!!

[Derek - Raymarine - Moderator]

Hi sailingriki

Thank you for your enquiry.

The original masthead wind transducer used by the ST50 range has not been available for many years, it's part number was D168 and was identified by the vertical tube at the end and the angular 'squarish' style cups.

The current masthead transducer, R28170 is identified by the 'egg' shaped body and the hemispherical cups and the R28170 is contained within the E22078 pack, which also contains a new masthead cable and mounting block.

The two masthead units are operationally the same, however the hemispherical cups are more efficient and will rotate faster than the older angular cups, giving a wind speed over reading of 30%.

The later ST60 and ST60+ instruments have a wind speed calibration and so this over reading can be corrected out. The ST50 and ST50+ displays did not have a wind speed correction and so they will over read the wind speed by 30%.

You can fit the new masthead cable, (we would recommend this is replaced due to the likely age of the old one - cable can fatigue over a period of time) and the new masthead Transducer and it will work with the existing ST50+ wind display, except the wind speed will over read by 30%.

regards