The Beach, The AT-Pro & The Prince(?) of Tides…

Since all is nil here in the colonies and since John Howland will never accept the fact that the White’s  Surfmaster is an infinitely better machine  for the beach than the AT-Pro, I will turn today’s post over to him and let him ramble.  If you happen to be an AT-Pro user you should find something useful in his words.   

John is a cultured person with the vocabulary of a highly educated sailor…. 





As most proficient UK beachcombers are (presumably) aware, 5p and 10p coins (along with 1p and 2p coins) are iron-cored. However, when they are found in ‘recently lost’ condition the ATPro reacts favourably to the copper wash exterior of the 1p’s and 2p’s, or the nickel wash of the 5p’s and 10p’s. BUT, when these coins have been exposed to prolonged periods in a saltwater environment the iron core ‘bursts’, whereby the coins invariable register as ‘Iron’ – similar to bottle caps – by setting-off the ‘Iron Audio’ mode. In this condition they are worthless anyway…or ‘Barfords’ as me and Jack Dey call them…as in:-

“Found anything Jack?”

“Yep, a couple of £1-coins, and a Barford.”

Though the ATPro’s ‘Iron Audio’ feature is a superb innovation – like when the first loaf of bread came sliced – relegating steel bottle caps to the dustbin of history, which on the face of it is no bad thing…but… BEWARE!

On a recent beach sortie and for some fortuitous and unfathomable reason I dug a dubious ‘iron’ signal and into the sandscoop came a ‘burst’ 5p. I checked the hole again, and a strong ‘77’ digital signal sounded indicating a £1-coin. Sure enough, in the next scoop of sand , up came a shiny £1-coin. The 5p had partially ‘masked’ the £1-coin having been directly above it or at the very least, overlapping it, thus presenting a dubious ‘Iron’ signal to the ATPro. The ‘Iron Discrim’ was set at ‘35’ my normal beach setting. I doubt whether a smaller coil would have separated the two, BUT, that £1-coin could have been a gold ring! You get my drift? The odds of a ‘burst’ 5 or 10p coin masking a gold ring are, well, who-knows-what, but certainly possible has as happened with the £1-coin.

John Howland taking a tea break....honest!

Bubba taking a tea break….honest!

I now operate the ATPro with the ‘Iron Audio’ facility ‘ON’, but with the ‘Iron Discrim’ to ‘15’ or less, in the hope that ‘bigger’ more valuable targets will overpower ‘burst’ 5 or 10p’s. I don’t how these settings affect US and Canadian users, though I understand that some Canadian coins can be more than a twinge in the rectal region. Perhaps ‘Bill from Lachine’ will chuck in his ten cent’s worth – all contributions gratefully received.



If you hunt beaches and bays where huge tidal ranges are the norm, what follows just might save your life. Those of you already aware of the ’12-ths Rule’ then I suggest y’all put the coffee pot on, or pour large Bourbon, or go and get your leg over, while I explain to the less knowledgeable.

Right! For you newbies it’s all about numbers…..Remember…..1, 2, 3 …. 3, 2, 1.

The Flood Tide (incoming) runs for six hours from LOW and HIGH Water; not at a constant flow, but slowly gathers speed galloping in during the 3rd and 4th hours of the flood, with the pace decreasing towards High Water. On some slightly shelving beaches where there might be up to, or over 400-yards of exposed foreshore, it races in faster than some people can walk and cutting off the unwary an consigning them to an untimely death. You can work out the speed of the tide by knowing its range and if you don’t know what ‘range’ means…don’t go out on a beach until you do; and that ain’t negotiable. An incoming (Flood) tide runs approximately for six hours at roughly the following rate:-

1st hour is equal to 1/12 of the tidal range… Rises 3-ft

2nd hour is equal to 2/12 of the tidal range…Rises 6-ft

3rd hour is equal to 3/12 of the tidal range… Rises 9-ft

4th hour is equal to 3/12 of the tidal range… Rises 9-ft

5th hour is equal to 2/12 of the tidal range… Rises 6-ft

6th hour is equal to 1/12 of the tidal range… Rises 3-ft


If say, there’s a 36-ft tidal range in your area, then you’ll see from the above scale, the greatest movement of water occurs during 3rd and 4th hours of the Flood (incoming) Tide. This is especially critical if you’re say, wreck hunting, at the back of a horseshoe-shaped bay backed by high cliffs.

Assuming then, you are hunting in a 36-ft tidal coastal location, the speed of the Flood Tide during the 3rd and 4th hours is rising at the rate of 1.8-inches per minute. Once the ‘tips’ of  the horseshoe are covered by the Flood tide – your escape route is now effectively blocked – you are in deep, very deep, doo-doo! Your only ‘out’ is by climbing the cliffs.

I never ceased to be astounded by the number of beachcombers who cannot read, or even grasp the rudimentary essentials of a Tide Table… after all, it’s basic knowledge not rocket science, as is getting a handle on local weather conditions. Here in Dorset, sadly, we lose at least one angler every year somewhere along our magnificent coastline and often on the deeply shelving, and unforgiving Chesil Beach, which in a fierce ‘South Westerly’ is a death trap….locals avoid it like the plague in these conditions; they know the fish will still be there the day after!

There’s a place I know where high value Spanish gold and silver coins can be found washing ashore where on a Spring Flood Tide the window of treasure hunting opportunity is about one hour. Whenever I hunt here, I ALWAYS carry a mobile phone and a smoke distress flare – just in case.



The archaeo-blogosphere is stuffed full with Richard-heads, thus:- 

“I am patient with stupidity but not with those who are proud of it”…..Edith Sitwell

I’ll see y’all in the bar!


Life is so much funnier when you have a dirty mind…..



Filed under Metal Detecting

12 responses to “The Beach, The AT-Pro & The Prince(?) of Tides…

  1. I have to agree with Dick on the choice of water machines. I have the AT Pro and the SurfMaster II and I would rather have the SurfMaster with me.

  2. Hi Ricardo:
    Can’t comment on the WHITES pi, as I’ve never used one, but it looks a tidy piece of kit for the surf /wet sand. As it is, I use a Sea Hunter II in those areas.

    But as far as the ATPro ‘International’ is concerned, in my experience, I have found that running ‘Iron Audio’ with a measure of ‘Iron Rejection’ improves performance and presents more information about the target, especially in rejecting iron/steel bottlecaps. I am of course talking about a beach environment.

    Iron Audio also allows adjustment of the mid-tone’s range to include all targets above the iron discrimination setting. The user is adjusting the cut-off between low-tone iron targets and mid-tone targets to better distinguish good targets. When Iron Audio is on in the PRO Mode, iron targets will not only be heard, but they will produce an even more distinctive response with multiple tones. For example, a nail will produce several fast low tones as the searchcoil passes over. A flat iron object like a bottle cap or steel washer will produce a very distinctive Low-High-Low response. I hope this helps answer any questions.

    Note to Kenny Briggs:
    Ignore what DS tells you about me. Alcohol never touches my lips.

    Happy daze!

  3. John’s reply above is in response to the following question, which was posted on a FB page:

    “I’m not going to go into depth because I save some things for my customers, but this article was written by someone that needs help understanding the AT Pro. Running any iron rejection cancels out the advantage of the Iron Audio. I should imagine we are comparing a Surfmaster PI to the AT? If not a White’s Surfmaster VLF is like a pea-shooter compared to a AT-Pro being a 44 Mag! The Surfmaster is a very loved machine but its day has long passed.”

  4. Shawn Himmelberger

    Good story. I wish I owned an at pro. My coinmaster gt has been finding me silver lately but I think iron does affect its ability big time.

    • Shawn JMO but I think if you stick with what is working and you start feeling comfortable with it’s operation you will be successful. Seems everybody today has to have the next “new machine” on the market no matter the price, and I don’t buy that philosophy.

    • Hi Shawn;
      Stay with what you know. Iron affects all machines, it’s just a matter of how you interpret what the machine is telling you. Are you using it inland or on the beach? You might not know, that the Coinmaster series were designed to locate coins (certainly pre-decimal old English pennies) lying at any angle from ‘end-on’ to ‘flat’….at ten inches and were achieving this feat over thirty years ago! Now, that’s performance even by modern standards.
      Regards & HH

  5. Jimnick

    Hi from continental Europe !

    We too, have steel cored low value coins, that will mask higher value ones in coin spills, for instance.

    The trick is to sacrifice one inch (or less) of depth by setting manually the ground balance to salt. The steel cored coins will now respond with a positive ID and in the coins range, unmasking other goodies at the same time.

    What about that one inch lost? Well, we can assume that most steel cored coins are recent and that we are talking about current, spendable coinage hunting. So who needs depth?


  6. Thanks Jimnick for the tip and for adding your name to the subscriber list. Appreciate it. Don’t be a stranger here….suspect we here have a lot in common with what’s happening there.

  7. supernova1c

    Hi Dick, I’m a little behind with my email alerts at the moment my friend. Hope you and yours are OK.
    I’ll speak soon so take care, James 🙂

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