shallow water depth transducers or heads or hacks?

[TiPegleg]

Long story short, is there a transducer depth head combo that will work in really really shallow water? I have a flat bottom and want to be able to dry my boat out (it was designed for this) but the minimum depth on my sounder is 2.6 ft. I can see how this isn't a big deal on a normal sailboat with a keel, but I don't have one.

I found this out while I was doing some maintenance on my instruments and when I went to test my depth sensor (ancient ST50 and original airmar P19) just for function. I was dismayed to find out that it was stuck at 2.6ft/0.8M. Thinking it was busted I tried everything including constructing an empty and then water filled tube. The depth flickered a couple of times to 2.5ft but that was it.

This may just be a matter of bypassing the ST50 and using another solution. I don't have an o-scope hand and really don't feel like hacking something together if an already off the shelf option exists. Also don't exactly mind trading out the transducer but its a large job with the stainless plug it was built into being made one with the hull after 25 years of "it just works".

Thanks.

[thinwater]

I will Follow. Having multihulls, I have noticed this many times. But it may matter less than you think. Even dinghies have to be very careful. Kayaks are OK.

• You can't sail in less than 2.6 feet. Not enough water for the foils to grip.
• High risk of grounding the motor. Bumps and snags make it less. Even a small outboard is nervous in under 30". You rev way down under 30" if you are smart.
• A boat hook or paddle works fine. Mostly you can see the bottom, even in brown water areas.
• Tide becomes a very big factor if you stop for long.

This is only knee-deep. I dock in water like that, and I have to pull the board up.

[SailingHarmonie]

The problem is the pulse length of the sonar is finite, and the transducer can not listen AND send at the same time.

This is a rather unusual problem, you might have to go to a chirp sonar, they MIGHT let you get around this. I would call Airmar. They make all the transducers and see if they have a solution for you.

[Grith]

Great info. I had wondered why both my sounder and fishfinder struggled in the really skinny water we often explore.
We sail and motor a lot in exceptionally shallow water and I had noticed losing all signal in very shallow water.