I'm not really sure what forum this should be posted in, but considering some of the answers are likely to be technical in nature, I'll start here.
I don't have a lot of specifics, but I am still going to try to get some answers on the best way to proceed.
This starts off as one of those typical 'friend of a friend stories.'
Someone told a buddy of mine that their are some naval anchors lost in our local river. All that is known is a generalized location (could cover several miles of territory) an approximate depth (30') 'fast moving water' (knowing our local river, I doubt that rate would exceed 3-5 knots) and that there are two anchors; one has cable attached to it, the other has chain (possibly as much as a hundred feet or so).
My question is this: Does anyone have experience trying to locate an object like this? If so, what is the best way to accomplish it?
Here are speculations on our part:
anchors are probably around 7' and weigh a couple of thousand pounds
the river bottom composition is mostly mud and mud/sand
visibility will likely be measured in inches
unless they were lost in the last 6 months (highly unlikely) they are already below the mudline
magnometers are prolly too $$$$ for our budget
grappling will likely produce a ton of tree stumps and other debris
Given this scenario, how would you go about locating something like this?
MichgnTechDiver
December 25th, 2002, 07:28 PM
Hmmmmm tough question. If you really want to find it, use an underwater metal detector. Thats the only answer i can find. You can easily find them for under $1000 and probably could find them on ebay cheaper. Plus, you can use them for much more than just these anchors......can we say pirate treasure!! lol
MichgnTechDiver once bubbled...
Thats the only answer i can find.
That idea has been discussed and disgarded already. Sorry for not mentioning that. The reason is that we do not have an exact location, and with miles of river to sweep, this type of detector would be extremely time consuming. Also, from what I have been told, they are only have an effective range of about 20'', and it is possible these items could be covered by a thicker layer of mud than that.
Thanks for the idea tho.
joens
December 25th, 2002, 08:48 PM
MichgnTechDiver once bubbled...
Also, just out of curiosity, what river is it?
nice try , you think he will tell you where it is.:D
joens
100days-a-year
December 25th, 2002, 10:53 PM
With a good color bottom machine it is possible to determine the approximate density of objects on and in the bottom.It is atrial&error method.1st set the scale to over 2ce the depth of the river,turn up the gain until you get a second echo.This will show up as a second line at double the known depth.In the first echo a hard return (dark in B&W,red in color)will be a dense object.The relative densities can be tested over a period of time on known objects until you can "read" the difference.I hunt fossils in rivers composed of mud,shell and sand bottoms which have a low density and occurence of fossils and limestone which is dense and a higher percentage of fossils.I can read thru several feet of mud and a foot of sand.good luck.
MASS-Diver
December 26th, 2002, 12:42 AM
Sounds like a tough search, 3-5knots is a prtty tough current as well.
I would say try to narrow down your search area, several miles is a huge area. Bribbing local fisherman, historians or whoever with beer is always a good call. Then , if you really can't get a mag (that's the only "good" way to look for something like this), I'd run over the target area with a good fish finder looking for anything that looks funny, with practice you should be able (at the least) to disguish between sunken trees and metal. That method would rely on lots of time and lots of luck.
Bottom line: get a mag or get a little tighter search area.
Good luck
WYDT
December 26th, 2002, 09:51 AM
Cave Diver once bubbled...
Given this scenario, how would you go about locating something like this?
Just wondering but why would you want to try to find these? Are they worth a LOT of money?
You should weigh the risk vs reward here. Unless those anchors are made of gold I'd forget about the idea. It doesn't sound like you have any experience in salvaging this type of thing and something that weights thousands of pounds in swift water is nothing to play around with. Add in 0 vis and other debris and it sounds like a great place to die... hmm, come to think of it even IF those anchors were made of gold I'd leave them where they were!
Maybe I'm way off base here but this just doesn't sound like a good idea.
Dive SAFE and Often!
Cave Diver
December 26th, 2002, 01:25 PM
WYDT once bubbled...
Just wondering but why would you want to try to find these? Are they worth a LOT of money?
Mostly just the challenge in it at the moment. I have not talked directly to the person who is supposed to know the whereabouts of them, so the info I have is mostly conjecture. The current speed is not an absolute, it is just an extreme possibility depending on where they might be at. Should the current actually be that fast, I wouldn't even consider a dive there. However, I tend to think some of the details have been exagerated (tho not necessarily on purpose).
That is why the first thing would be is to determine a good way to find them if we are able to narrow a search area down from say, 2-3 miles of river to several hundred yards.
As far as the low vis and entanglement hazards, that is our 'normal' diving.
Regarding the experience in finding and salvaging them (if possible), several of the people who would be working on this have experience. However, the FINDING is the hard part at the moment as the things salvaged before where either at a known location, or insurance or some other company with deep pockets was footing the bill for a search operation. As it stands, this is just kind of a personal project among several close dive buddies, thus the need for more cost effective (tho possibly more time consuming) ways to approach it.
Thanks for all the input so far.
WreckWriter
December 26th, 2002, 01:32 PM
Just come to Ft. Lauderdale, those things are all over the place here. They're really not worth much of anything.
Based on the criteria you've given (objects buried in mud in snag filled area), you're basically SOL without a mag or similar device.
Do the research first. Find out if they really exist and, if so, a better location if you can.
Tom
Cave Diver
December 26th, 2002, 08:40 PM
WreckWriter once bubbled...
Just come to Ft. Lauderdale, those things are all over the place here. They're really not worth much of anything.
That is in the plans for sometime later this year. One of my buddies collects nautical stuff. The rest of us are just in it for the challenge.
diverberr
December 27th, 2002, 09:29 AM
If they're modern type ship anchors, they are worth a lot of money. Given the size you mentioned, these anchors could be up to several tons and worth several thousand dollars apiece.
However, recovery is not so easy unless you have a barge and crane available ( my preferred recovery method), and even then, you still don't have a definite position.
If you can't get your hands on a mag, you're probably SOL, as with no vis, and no definite position, a towed diver search is out of the question. A mag or towed metal detector are definitely your best bets here.
Any that we've found have been by chance, then you can mark the position and go back later with a small barge. The biggest one we've found is about 10 feet high, a plow type oil rig anchor with about 500' of 2" chain attached. It was lost when the rig broke loose in our harbour and was never recovered. We haven't gotten that one yet, but it's in the works.
Usually, in a strong current, a hollow will form around them, so your anchors may be sitting visible above the bottom unless the bottom is terribly soupy. It's just possible (though unlikely), that you may locate them with an echo sounder because of this. It still requires a great amount of luck in actually being able to pass directly above them, but you'd see (or at least feel) them when you went down.
See you on the bottom,
Al.
Cave Diver
December 27th, 2002, 01:35 PM
diverberr once bubbled...
If they're modern type ship anchors, they are worth a lot of money. Given the size you mentioned, these anchors could be up to several tons and worth several thousand dollars apiece.
However, recovery is not so easy unless you have a barge and crane available ( my preferred recovery method), and even then, you still don't have a definite position.
They should be fairly modern, possibly several years old. And yes, we do have a barge/crane set up at our disposal. Unfortunately, no mag. Recovering them will probably turn out to be easier than finding them.
WreckWriter
December 27th, 2002, 04:34 PM
diverberr once bubbled...
If they're modern type ship anchors, they are worth a lot of money. Given the size you mentioned, these anchors could be up to several tons and worth several thousand dollars apiece.
Several thousand dollars? Hehehe, good luck. You'll never get enough to pay for renting the truck to haul them. That's true here, maybe not where you are but I'd check before investing much time or money.
Tom
WreckWriter
December 27th, 2002, 04:36 PM
Cave Diver once bubbled...
Unfortunately, no mag.
If you want them badly enough, mags can be rented. Do a google searh on "magnetometer rental".
Tom
diverberr
December 28th, 2002, 11:03 AM
WreckWriter once bubbled...
Several thousand dollars? Hehehe, good luck.
Tom
Tom,
Guess the market's different in Florida mate. We've gotten as much as $9500 (Can.) for a big one with chain. That's about $5800 (USD). It helps to have a barge at your disposal without a rental fee though.
Al.
WreckWriter
December 28th, 2002, 01:40 PM
diverberr once bubbled...
Tom,
Guess the market's different in Florida mate. We've gotten as much as $9500 (Can.) for a big one with chain. That's about $5800 (USD). It helps to have a barge at your disposal without a rental fee though.
Al.
Wow!
If I thought I could get anywhere near that I'd buy a barge and go into the business of anchor hunting!
Did you sell to a shipping company for re-use, a hotel (or whatever) for display, or a scrap company? Perhaps there's more of a market here than I think.....
Tom
diverberr
December 28th, 2002, 05:44 PM
WreckWriter once bubbled...
Wow!
If I thought I could get anywhere near that I'd buy a barge and go into the business of anchor hunting!
Did you sell to a shipping company for re-use, a hotel (or whatever) for display, or a scrap company? Perhaps there's more of a market here than I think.....
Tom
There's actually a company here that will buy anchors, chain, etc., and resells them to shipping companies.
WreckWriter
December 28th, 2002, 06:58 PM
diverberr once bubbled...
There's actually a company here that will buy anchors, chain, etc., and resells them to shipping companies.
Interesting. At that rate its damn near worth getting 5 or 6 together and putting them on a train up to you.
Cave Diver
December 28th, 2002, 07:07 PM
WreckWriter once bubbled...
Interesting. At that rate its damn near worth getting 5 or 6 together and putting them on a train up to you.
Don't forget my 'finders fee' cut for starting this thread and giving you the idea! :D
