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Submersible dredge ???

Keene and others have mass produced them for many years. The suction nozzle style has better recovery as it uses the whole hose for classification and the powerjet style blasts the gravels immediately prior to introduction to the classifying tray inside. Problem is with submersibles if tipped left,right,up or down out goes your gold!! AND they back fill immediately from tailings as sittn' on the bottom so you must suspend them RIDGIDLY with steel straps from a floatation devise to prevent side to side loss. So then why use something with bad recovery when ya need to use floatation anyhow,just get a surface dredge and be a much happier wealthier miner-tons a au 2 u 2 -John :laughing7:
 

Well said John :thumbsup: that is what I am thinking. Just make some pontoons out of 5 or 15 gallon barrels. Suspend the whole system tightly and off ya go !
 

Yeah, I don't see too many applications for submersibles other than outfitting them with high volume electric bilge pumps and running completely incognito.
Someone comes to check you out, all you pop up with is your hookah regulator and say you sniping.
Of course it would need some bit of camo on it to blend in with the riverbed if not very deep otherwise it will stand out easily.

A buddy of mine has a massive 6" submersible, no amount within reason of electric bilges and batteries would operate that thing effectively.
As it is the 4" that I have requires two 4000gph pumps to make it work, another 4000gph pump would make it work GREAT but at a bulk, weight and battery life cost.
I did make a 3" with a 1000gph 12v overvolted to 19.2v that worked amazingly well.

But now we are going way off into another topic. lol
 

NeoTokyo said:
Yeah, I don't see too many applications for submersibles other than outfitting them with high volume electric bilge pumps and running completely incognito. Someone comes to check you out, all you pop up with is your hookah regulator and say you sniping. Of course it would need some bit of camo on it to blend in with the riverbed if not very deep otherwise it will stand out easily. A buddy of mine has a massive 6" submersible, no amount within reason of electric bilges and batteries would operate that thing effectively. As it is the 4" that I have requires two 4000gph pumps to make it work, another 4000gph pump would make it work GREAT but at a bulk, weight and battery life cost. I did make a 3" with a 1000gph 12v overvolted to 19.2v that worked amazingly well. But now we are going way off into another topic. lol
Click to expand...

..and the noise factor..with so much power being produced
 

NeoTokyo said:
Yeah, I don't see too many applications for submersibles other than outfitting them with high volume electric bilge pumps and running completely incognito.
Someone comes to check you out, all you pop up with is your hookah regulator and say you sniping.
Of course it would need some bit of camo on it to blend in with the riverbed if not very deep otherwise it will stand out easily.

A buddy of mine has a massive 6" submersible, no amount within reason of electric bilges and batteries would operate that thing effectively.
As it is the 4" that I have requires two 4000gph pumps to make it work, another 4000gph pump would make it work GREAT but at a bulk, weight and battery life cost.
I did make a 3" with a 1000gph 12v overvolted to 19.2v that worked amazingly well.

But now we are going way off into another topic. lol
Click to expand...

What type of your buddy's subbie of dredge? is it the Suitcase dredge as mentioned by Russau ?
 

TGP: The Sound is just a hum under water and the rocks going through the nozzle.

Gelmac: This is what it looks like.
underwater dredge.webp
 

Absolute worst dredge ever made-look at discharge-blocked withing 5 minutes as sitting inches from the bottom. Now the front style suction nozzle mixes all the gravels sucked up immediately to that MINISCULE box with lousy recovery. Suction nozzle needs to be at least 10' from the box but no fix for that insipid recovery system. A few degrees off left/right and viola recovery box dumps out. Good to blow off overburden and that's about it. John
 

(EDIT) oh... didn't see this was an old thread... anyway...

heres one I saw a few years ago from Steve Herschbach
jp000905.webpjp000906.webp

” SUBSURFACE DREDGE ( SUCTION NOZZLE )

PART # ITEM
KESS4 4” SUBSURFACE TUBE
KEPF25 2 – 2½” FLOATS
KESN42 4” X 2” SUCTION NOZZLE
KEP103BH 4HP HONDA PUMP W/BASE PLATE
OPTION - KEP103BCH 4HP PUMP W/T80 AIR COMPRESSOR
KESH4 15ft. 4” SUCTION HOSE
KEPH2 16ft. 2” PRESSURE HOSE
KESS72 4 – 4” HOSE CLAMPS
BJRB200125 2” X 1¼” REDUCER
KUPHC2F 2” PRESSURE HOSE COUPLER
KUSH15 4ft. 1½” SUCTION HOSE
KESS24 4 – 1½” HOSE CLAMPS
KESS32 4 – 2” HOSE CLAMPS
PANMM 6” MINERS MOSS
KEFV20 2” FOOTVALVE

NOTE: Frame is not included in this price because you will need to build your own. Tubing can be bought from Greer Tank. You will need 20ft. of 1” square aluminum tubing. See picture for simple frame assembly.

Two items of importance. First, I opted for a suction nozzle design as I wanted to allow the gold to settle before it gets to the box and to reduce the chance of the riffles being "blown out" should the prime be lost in the main suction hose. An alternative would be to use a 4" power jet mounted directly to the tube, which is how Keene normally did it.

Second, since I used a suction nozzle, I cut the tube opening into the box back far enough to insert the 4" hose into the tube and clamped it down. This shortened the overall length and eliminated a clog point.

Thye entire unit weighs and costs about the same as a 2.5" surface dredge. It burns the amount of gas a 2.5" dredge would, saving more costs and weight.

Recovery issues with a subsurface are simple. The riffle is small, and must be open to capture gold. If you hog material, you will bury the riffle, and lose more gold. If you are getting into gold, check the riffles to make sure they are clearing properly, and then slow up on cramming material through the unit.

These are great unit for hit and run operations where you have coarse gold. If all you have is fine, flaky gold losses may be prohibitive. The longer term the operation, the more gold will be lost over time. For longer term, relatively stationary dredging operations, use a surface type dredge instead.
 

Last edited:
Yup, I agree, recovery is NOT the best with this unit, thus why I would only ever run it in an electric design.
There are much better alternatives.

Now what I have come up with to improve upon the design is to grab some GoldHog mat and line it from the front of the jet to the box.
It will help increase recovery but it is still not the best option.
 

I think Glen Oates has used a screening method with the subbies that is good also on improving recovery.
 

Glen Oates also known as " micropedes1" has used the Suitcase dredge a (8 inch) to " move a sandbar and save as much gold from the sand as possible. He used a suction nozzle to allow stratification along the hose. The sand spilled on to a slick spreader plate, followed by a 80 mesh profile screen. " He describes his use over on the "Goldminers" on yahoo groups.

What I learned that a submersible - I am talking specifically about the Suitcase dredge here- is used by some dredgers to remove overburden as it is quite effective in that task. Improving fine gold recovery on a Suitcase dredge requires a bit of add-ons and screening system or a way to hide the gold out of the bigger cobbles and gravel or it will be scored out the end.
As it does not have a pre-screening area to classify , unlike the surface dredges. There is an area of improvements here that requires further investigation.
 

winners58 said:
(EDIT) oh... didn't see this was an old thread... anyway...

heres one I saw a few years ago from Steve Herschbach
View attachment 1089895View attachment 1089896

” SUBSURFACE DREDGE ( SUCTION NOZZLE )

PART # ITEM
KESS4 4” SUBSURFACE TUBE
KEPF25 2 – 2½” FLOATS
KESN42 4” X 2” SUCTION NOZZLE
KEP103BH 4HP HONDA PUMP W/BASE PLATE
OPTION - KEP103BCH 4HP PUMP W/T80 AIR COMPRESSOR
KESH4 15ft. 4” SUCTION HOSE
KEPH2 16ft. 2” PRESSURE HOSE
KESS72 4 – 4” HOSE CLAMPS
BJRB200125 2” X 1¼” REDUCER
KUPHC2F 2” PRESSURE HOSE COUPLER
KUSH15 4ft. 1½” SUCTION HOSE
KESS24 4 – 1½” HOSE CLAMPS
KESS32 4 – 2” HOSE CLAMPS
PANMM 6” MINERS MOSS
KEFV20 2” FOOTVALVE

NOTE: Frame is not included in this price because you will need to build your own. Tubing can be bought from Greer Tank. You will need 20ft. of 1” square aluminum tubing. See picture for simple frame assembly.

Two items of importance. First, I opted for a suction nozzle design as I wanted to allow the gold to settle before it gets to the box and to reduce the chance of the riffles being "blown out" should the prime be lost in the main suction hose. An alternative would be to use a 4" power jet mounted directly to the tube, which is how Keene normally did it.

Second, since I used a suction nozzle, I cut the tube opening into the box back far enough to insert the 4" hose into the tube and clamped it down. This shortened the overall length and eliminated a clog point.

Thye entire unit weighs and costs about the same as a 2.5" surface dredge. It burns the amount of gas a 2.5" dredge would, saving more costs and weight.

Recovery issues with a subsurface are simple. The riffle is small, and must be open to capture gold. If you hog material, you will bury the riffle, and lose more gold. If you are getting into gold, check the riffles to make sure they are clearing properly, and then slow up on cramming material through the unit.

These are great unit for hit and run operations where you have coarse gold. If all you have is fine, flaky gold losses may be prohibitive. The longer term the operation, the more gold will be lost over time. For longer term, relatively stationary dredging operations, use a surface type dredge instead.
Click to expand...

I also saw that ad before , but didn't pay attention until I found the suitcase dredge building plans and use.
And agree with you that a subbie should only be used where is weight issues or there is difficulty in access to certain areas should that be a concern. For coarser gold it works, for fines better use a surface one, you will eventually recover more using the right screening system.
 

russau said:
my friend from New Zealand (Trev Alty) built one and has pictures/directions on how to build it over on www.goldminers@yahoogroups.com in the photo/files section. i hope it is ok to post this link???
Click to expand...

Yeah an old thread 8-) . The yahoo group that Russ refers to is at this address:

https://groups.yahoo.com/neo/

Then just type : Goldminers

in the search box and select this one : https://groups.yahoo.com/neo/groups/Goldminers/info and log from there.

Just an update to the above link :thumbsup:
 

Last edited:
Bringing this one back to life a bit.

So as I mentioned, I have a 4" Subbie and I have been thinking about trying to it move several yards of sandy material to get to some bedrock.
This sandy material also has some fine gold and small pickers in it along with tons of iron trash and lead.

So far my plans are to run GoldHog matting before the sluice trap and a 5' long section of corrugated 4" tubing.

The purpose of running the tubing after the sluice is to offer an extra change for gold recovery as the corrugated rows make great drop riffles.
A few people that I have seen use 50' and 100' lengths of the 4" tubing for gravity dredging say that most of their gold winds up in the first several feet but the fine stuff will still travel on most likely.

I have also been thinking about lowering the ceiling height just in front of the sluice trap to help increase velocity in an attempt to keep the riffles active.
This is only an idea and may blow more gold out than helping to retain it, I dunno but its worth a test and try.

I have been thinking about adding a 3-5' section of corrugated between the box and suction nozzle to be a catch for all that pesky hematite, black sands and those ever so annoying nuggets. ;)

I will run my conventional surface 2.5" dredge after it to see what my loss is.
 

ive also been wanting to build one of these underwater dredges of my own design. Ie got all of the parts andnow I just need to get off my--------------- and do it.
 

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