游艇百科
Depth sounder
Depth sounders on sailing yachts: transducer types, survey checks, offset errors, and FairHelm limits on trusting a single shallow reading.
这是什么
A depth sounder (echo sounder) is an instrument that measures depth under the hull using a transducer and displays depth below transducer or, when offset correctly, approximate depth below keel or waterline.
Anchor
Thru-hull and in-hull transducers are both common on boats FairHelm sees. Fouling, air in the laminate path, and wrong keel offsets create false comfort in Baltic shallows. FairHelm compares readout, transducer condition, and charted depth during trial.
FairHelm judgment
FairHelm judgment: dead displays, wildly wrong offsets, and transducers painted over with antifouling are survey items. A glowing number is not a guarantee of keel clearance. Confirm what the number means on that install.
Limits
We do not invent accuracy tolerances for every maker. Soft mud and weed confuse returns. Use seamanship and a surveyor, not a single beep.
常见问题
Q: Is depth below transducer the same as under the keel?
A: Only if the offset is set for that. Ask what the display is configured to show.
Q: Can antifouling ruin a transducer?
A: Paint on the face can kill the signal. Check maker guidance.
Q: Does a plotter depth overlay replace a sounder?
A: Overlay still needs a working transducer source.