Raymarine forum

Having problems getting a dst800 to seat in the thru hull with valve included with the transducer.

I am using yellow o-ring but transducer is very difficult to tighten and will not seat to the bottom of the thru hull. It appears to be about 1/4 to 3/8" from seating flush with the external surface of the thru hull.

Is there some trick to seating the yellow o-ring in the insert that would fix this?

Welcome to the Raymarine Forum Stephen,

The rotational force which you have described for the transducer's locking ring is considered normal with non-lubricated o-rings. After I applied a light coating of biodegradable soap to the o-rings of my DST-800, the force required to rotate the locking ring was reduced significantly, permitting the transducer insert then be easily within its housing.

Yes, I tried that using the silicone grease that came with it. That did make it easier, but it never went all the way in. Is that normal?

No. When fully seated, the depth sensing portion of the insert should be flush with the face of the housing. It is recommended that you verify that both o-rings have been lubricated, that you have not damaged the housing and insert's treads through cross-theading, and if not, that the locking ring be further rotated to force the insert further into its housing.