[C320-list] Old Autohelm ST50PLUS knotmeter (speed & temperature) replacement

[Onat Dogruer]

Hello all,
A couple of weeks ago, our original knotmeter failed (ours is 1998, hull # 546).  I was researching a direct drop-in replacement so that we didn't have to make a full system upgrade.I spoke with Airmar (manufacturer of Raymarine transducers) and their distributor, we exchanged a few photos and dimensions - the drop in replacement (a newer model) is identified as model:  Airmar ST800-INS.  This is only the transducer insert and you don't have to change the housing. It fits directly into the old housing.  The only issue was the height (from hull to the floor board covering the unit in V-berth) as we had to take the plastic cap off and trim the plastic housing 1/4 inch on the top. This has no effect on performance; purely cosmetic.  You would then splice off the old wiring and connect to this transducer's wiring, matching color by color.  Very easy process; doesn't require a haul out.  Once I had the product in hand, total amount of time required was 2 hours.
In case anyone else has a need to replace...
Happy sailing,Onat#546