I fish a old sand mine that’s mostly covered with hydrilla to the surface with big open pockets and was wondering if a fish finder can locate bass through the  thick vegetation before I buy one to bring out there?

Yes and no.

Highend 360 degrees scanning sonar can locate fish in aquatic cover. Side scanning HD and forward looking sonar with Chirp can isolate fish in cover. 2D with Chirp can locate fish in cover directly under the boat. All the sonar units with this capability are expense.

Tom

 

Manual gain setting is your friend.

In this case, I’m going with short answer equals ‘No.’ You might be able to see fish hanging on weedlines, suspended out in the open holes, etc., but to just buy a unit and bring it out there with (I’m assuming) little to no experience reading them, or setting them up (dialing in), you won’t be able to ‘shoot through the weeds’ and simply see fish. Even in the best case scenario, if the vegetation is pretty thick and heavy, ability would be extremely limited. Save your money. JMHO

I would also go with “no”

 

you even hear Pros who are experts with electronics say they can’t see bass sitting on bottom or in weeds with the latest live units 

Uhh no! ?

 

Nope - even the best get 'confused' if the bass (or any fish) is hugging any type of cover.

 

Bass in thick weeds - hidden

Walleye nestled up to a rock - hidden

Crappie hugging the branches of a sunken tree - hidden.

Fishing pockets, side scan would be almost useless.  A good high definition Structure scan might if they are suspended a foot of so away from the structure, but if you think you are going to just cruise over those holes and fish for the ones you see, you're going to be passing up a hellava lot of fish.   By the time you get the boat over the hole, the fish are going to be spooked.  

In situations like that, I generally use something like a Senko or other slower falling bait and fish a couple of pockets away.