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Chris's Metal Detecting Page njminerals.org is mainly about [what else?] mineral collecting,
but Treasure Hunting is somewhat related, so here goes... When I decided to graduate from an older White's, I picked up a Tesoro Tiger Shark. Many people out there seem to be wondering how the Tiger Shark does in the ocean. This review was originally written when I'd had little experience with the 'Shark. The article has been updated to reflect not only the time spent at the beach, but also some fresh-water trips and land detecting with this great unit. Tiger Shark in Salt Water If you're inclined to "skim" or came here looking for a quick summary, here it is: the Tiger Shark is GREAT for fresh water and for land & beach detecting, and OK for salt water. If detecting in salt water is your PRIMARY goal, you might want to look into a pulse induction machine such as the Sand Shark. Though PI lacks discrimination, experienced PI users are very good at picking out coin- and ring-sized signals. The Tiger Shark is a single-frequency VLF detector. That means moving salt water (i.e., waves lapping over it) tends to cause falsing. The fact that you can even take a single-frequency VLF into the ocean and not have it freak out to the point of uselessness is pretty remarkable. The engineers who designed the Tiger Shark seem to have done everything possible to minimize this sort of thing.
If you are hunting the most heavily-mineralized black sands, the factory-preset Tiger Shark will have an overwhelming number of false signals in the saltwater, especially when the ocean churns up the sand and carries it over the coil. The way around this is (1.) turn down the sensitivity adjustment, which is inside the case (don't open the case anywhere near the water!) and (2.) move the coil as slowly as possible. Yes, the detector is usable in salt water, but it takes a little while to get used to the constant clicks that moving salt water and black sand particles cause when they move across the coil. Once again, reduced sensitivity is the answer. The lack of coins from the ocean field test was not because the detector couldn't handle it, but because the conditions weren't right. Normally, coins and other dense objects work themselves downard very quickly. Within just a couple hours, they're out of detector range altogether. Somewhat less-dense objects (bottlecaps, for example) are in a zone that's not as deep. This is the zone you're going to be hitting with most any detector you take into the ocean... UNLESS you are lucky or skilled enough to find a "trough" where the ocean has exposed the denser objects. These troughs do not last long. If you do not find one of these troughs, the wave action will have worked coins and rings much farther down into the sand than a metal detector can reach. The Tiger Shark will detect them if they're there and in a reasonable depth (say, 6-10 inches). Based on my finding a bottlecap, small washers, aluminum can fragments, and some nails, I'd have found coins if they had been in that layer. The point here is that the Tiger Shark could pick out small targets and get consistent signals, even if there was some chatter. The detector seems to have run into a couple earring backs or tiny pieces of foil, because a couple times there were good signals that kept escaping the scoop. This was not falsing; there was something there. It's easy to find pieces of metal so small that they fall right through the mesh. The most important thing about any signal is salt water is whether it's repeatable. I have found that false signals tend to occur under the following conditions in the ocean: - at the endpoints of each sweep - when you accidentally hit bottom with the coil - when you move the coil too abruptly - when there is too much black sand and bits of rusty iron all over the place There's a simple way to deal with the first three conditions: Just focus on the middle portion of each sweep when you hear the signal. If you get a signal that happens only at the endpoints of your sweep, not in the center, it is a false. The fourth condition might mean you'll have to try a different beach, but turning down the sensitivity can help a great deal. You should still be able to find coins, but you won't be picking up every tiny piece of crumpled-up foil or flake of rusty iron. Of course, some of those small-metal signals could be thin gold chains, so maybe you'd better dig them! Once you master the learning curve for dealing with false signals, processing the audio and visual data through the best computer in the world (your brain), you can get good results with this metal detector in the ocean. If you try different areas and settings, you can develop a good feel for these techniques in as little as two or three trips out. The unit was clearly able to handle the salt water, but the ocean became too rough for my liking as clouds rolled in and it became windy. Too many facefuls of water finally took their toll. I can't count how many times I dropped the scoop or how many times a wave knocked the coil flat up against the shaft while I was trying to detect. Fighting the waves can take the starch out of a person pretty quickly. Tiger Shark in Fresh Water Some people have no trouble detecting in the ocean. I'm not talking about the choice of detector either. I'm talking about getting slapped with waves constantly, not being able to keep your footing, having to watch out for undertow and riptides, etc. There are some aspects of ocean detecting that are a blast, but fresh-water detecting is generally much more tranquil. After a day when the sky turned gray and the ocean turned rough (while I was still in it), I decided I might prefer detecting lakes instead. We headed out to a lake up north. Despite the mosquitos, we had a great time. The Tiger Shark revealed a Mercury dime in the first ten to twenty minutes. On a second trip, after being in the lake for a while and digging a few wheaties, I found a 10k gold ring. This wasn't a side-by-side comparison with another detector, but it was clear the unit was getting good depth. Having used a super heavy-duty scoop, I found that it took sometimes two or three full scoops to bring targets up from the bottom of the lake. I don't know what depth that is, but it's deep. One scoopful is probably reaching a good seven or eight inches down. Pinpointing wasn't hard, because the white coil is easy to see in the water. This was a good design move. Using the Tiger Shark in fresh water is a real joy. Submersible detector, submersible headphones. It makes a distinct "quack" sound when you find a target. Discriminated targets give a more broken-up sound, as you'd expect. I found that using the T.S. in All Metal (Fast) mode was also a lot of fun in the water. More junk, but more coins too. Tiger Shark on Dry Land The Tiger Shark achieves good depth on land. It doesn't get the depth of a Tejon (not many detectors do), but it's pretty respectable in its own right. In a heavily-pounded park, I found two different Barber dimes, each at 7" to 7 1/2" depth. The signals were not loud, but they were consistent. I didn't see any other detectors around that day. That might be because it was raining steadily. The Tiger shark is just as pleasant to use on land as it is in your favorite lake. What's really nice about this unit as a land detector is that you don't have to worry about a plastic bag or other makeshift rain covering for it. If you're out detecting and it starts to rain (which it so often does), you won't have to quit. That can mean a lot if you took the day to drive somewhere you can't easily return. If I were going to a place like that, such as a special one-time-only dig, I wouldn't hesitate to grab the Tiger Shark. Bring along a rain poncho and a change of socks just in case. There is also a unique kind of joy in looking out the window, seeing a torrential downpour, and actually saying "I'm going metal detecting!" Sure, you'll get filthy, your shoes will be caked in mud, your pants will be caked in mud, but so what? Obviously, don't go out and get hypothermia.... but the point is that the Tiger Shark can easily handle the weather. How many detectors can you safely hose off with water when you're done for the day? Headphones and all! Because it is completely submersible, the Tiger Shark is probably the most versatile metal detector I've tried. Since it's made as a water machine, you might not expect it to do that well on land against regular metal detectors, but it does. In fact, its depth is better than many of the land-only metal detectors from just a few years ago, and some of the ones from today, as well! Unless you're a salt-water-only detectorist (in which case you might want to get a PI unit such as the Sand Shark), the Tiger Shark is a winner. |
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