F75 and Salt Water Beach Detecting with Black Sand

[LawrencetheMDer]

Searched back 1 1/2 yrs and could find nothing regarding use of the F75 on salt water beaches with black sand on the various forums. I hunt Gulf beaches and considering the F75 w a larger coil (15" Fisher or other) to cover more ground than my Excal. I'm concerned that a single VLF machine (although I love the thought of a 13k hz machine for gold detection) will not be able to handle black sand, and I come across a lot of it. If I ground balance over black sand will that remove noise related to the black sand? And what depth can I expect for the standard coil or 15" Fisher on dry salt water beaches? Thoughts appreciated.

 

[Nauti]

It won't handle the wet sand very well let alone black sand.It won't cover more ground than your excal either.........it will area wise but the excal will search more ground at depth.Adding huge coils can does'nt always pay either......they are great for toy cars etc at depth but on ring sized objects they can be less sensitive and no deeper.Stick with the excal and just cover the ground more accurately.

 

[tvr]

I don't generally us my F75 LTD at the beach now, prefer a CZ, Excal or a pulse induction detector depending on conditions.

That said, when I first got the F75 LTD, I did spend a fair amount of time with it at the beach. Over all, I liked the 10 inch concentric coil the best on salt water wet sand and over black sand. It will ground balance to all the beach conditions I found; but you need to stay on top of the ground balance. If you run a zig-zag or cork screw pattern on the wet sand, you will more than likely need to adjust setting as you travel the pattern. I ran all-metal and looked at the ID to get an idea of what the target might be. You can run all the dry sand you want without changing the setting, but when you get to the wet, small changes in ground balance setting makes a difference in how well the detector finds targets.

It is very sensitive to small stuff. I've found 1/8th inch diameter sequins in the wet sand. Took a while to find what the detector actually hit when I ran across those. It also sounds on the small thin flakes of rusted iron the lay scattered on some beaches. Those iron flakes sound out with a boing kind of sound with a bit of echo on the end and are easily identified by sound. For me it gets annoying listening to the F75 on a beach that has those.

The black sand is not much of an issue as long as you stay on top of the ground balance. It gets good depth, I was finding targets at depths close to what I'd expect with an Excal or CZ. It takes more effort to hunt with the F75 since it hits small targets that my other beach detectors don't even see and in that you really need to stay on top of the ground balance.

The 10 inch concentric coil was a little more forgiving with respect to needing constant adjustment than the 11 inch DD. I did not have the 15 inch coil to try.

The Gulf coast beaches that I have been to have had less black sand and much less rusted iron flakes that I've encountered on Atlantic coast beaches. I used my F75 LTD on beaches in the Kitty Hawk, NC, Myrtle Beach, SC and Fort Lauderdale, FL areas. Have not used it on visits to the Gulf coast.

For the past couple of years, I have not packed the F75 LTD for beach trips, I stick with the CZ, Excal or the PI detectors depending on where I am going. I just like the quieter experience of not hitting on the tiniest piece of metal.

 

[tvr]

Did a little searching and found some of the posts on using an F75 or F75 variant on the salt water beaches from 6 to 8 years ago are not all fully intact. tinfoil posted a bit about settings and markg did a video. Mark did an update post here (look at second from last paragraph): http://www.findmall.com/read.php?37,2280501,2280501#msg-2280501

... and note from Mark's post that a video can be found by searching for “Wet sand testing the Fisher f75 at Holden Beach, NC. “ where markg posted it on youtube.