Replacing a Raymarine ST60 depth sounder with a B&G DST800

[Hillbillybuddha]

Recently bought a boat workout much in the way of electronics. Besides Nav lights, it has a Raymarine ST60 depth sounder. I bought a B&G zues3 system and I'm planning on adding that system to the boat once I get a bit further south. My issue is that the Raymarine has started to intermittently stop working. We're on the ICW with a fairly deep keep. I'd have no issue replacing the depth sounder in the water but looking at pictures, I'm not sure it's a simple swap. The Raymarine is threaded for its entire length while the B&G looks like it's sealed with an O Ring. Am I missing something? Maybe I'll require a haul out, which is fine but doesn't fix the problem until I get to a boatyard.

[Tetepare]

The old ST wiring is notorious for bad connections and shorts. Good chance that's what it is, though the paddle wheel sensor is rated/ guaranteed for far less than whatever it's current age is. I'd start jiggling wires, particularly near the display.

AMHIK. OK, I'll tell you- I'm still trying to figure out which connections can be saved and which have to be replaced in the ST ratnest from the former owner.

[tkeithlu]

+1 on Tetepare's good words. I think your boat has a solid fiberglass hull - no core. That being the case, you can glue the new transponder on the inside of the hull with anything from 3M 5200 to silicone, and it'll read right through it. Depth sounder transponders are pretty bullet proof.

[OldGreyB]

+1 on Tetepare's good words. The transducers are typically Airmar brand and very rarely fail.

Since you are currently on passage, check the connections on the rear of the ST60. The ST60 although a legacy product, it was designed and manufactured before "design obsolesce" became part of the marketing & sales world, so they last a long time.

Remove the ST60 from the panel and check for corrosion on both ST network plug and the especially the transducer leads and connectors. May even pay to re-terminate the transducer connectors at the ST60 if the wire and connectors are showing any form of external corrosion. Also as you state this is the only instrument, check the power end of ST network while you are at it. This will have a red for Positive and Black for negative 12Vdc , and the yellow shrunk back on the lead. Ensure you have good connections at that end too.
You may be pleasantly surprised with the outcome.

[smac999]

if the existing transducer is depth only without a paddle wheel. it will be screwed permanatly from underneath the hull. you need to haul the boat to change.

generally only paddle wheel ones pull out so you can clean them.