8 inch dredge build

build an 8 inch dredge hoping to run it of 3 keene 500hp pumps and 13 hp honda motors wanting good suction any one done this who could give some advice thanks

was similar on trademe last year maybe google search images it may still show up. may have been a triple jet 6" now I think of it.

i remember seeing that mine is going to be a triple also just trying to get as much info as i can befor i do power jet cheers

Hi I’m no dredge expert but have seen that problems have arose with the gold overshooting with a high power 8 inch. Have seen a three way splitter on seperate tables and also longer sluices.
Good luck

Diesels from rie quip in motueka

Hey mate
Your best bet is to go a p1500 pump from Keene running on a 40hp motor on a diesel setup (kubota or similar) this will give you reasonable depth however if you want serious suck and hence greater productivity and depth ( less blocks) and wanting to with run a longer hose you can run x 2 p1500 on a 80-100 hp option in diesel. This will give you depth down to 50 feet.

If you want a petrol options going with 2 x 23 hp petrol’s using a p350s pumps will do well on an 8 and be essentially equivalent to 1 x p1500 pump.

The p500 keene pumps are a good pump but they are suited more for pressure and they will be underdone on a 8 inch setup if you want lots of suck. Plus running 3 x 13 hp petrol’s you will use a lot of fuel.

In terms of your powerjet setup id stay away from the triple jetlog setup. Your best to stick to a dual or if running 2 x p1500 a quad jet would be the best.

hope that helps

i agree with what your saying but im using 2 of the motors and pumps of my old 6 inch and have just bought the 3rd motor and pump already.do you think the suction want be good at 15 feet deep thanks for your advise

yeah i think to 15 feet you should be alright but you will have more plugs up and suction will back of a lot at those depths id say. You might have to shorten your hose a bit to compensate. Just make sure you use the same diameter jetlogs that you ran on your 6 with those pumps on your eight. which would be around the 28 mm diameter.

Also try and keep your high pressure hose from the discharge of the pump to the powerjet as short as possible so as to reduce frictional losses within the hose to a minimum.

jet logs was the next thing i was going to talk about.when i made my old 6inch i took the jet log diameter of my mates proline 6 inch and this worked very well with my keene pumps but after measuring them they were 36 mm inside diamerter whats your thoughts

You need to match the pump to the jet logs.

Prolines pumps are rated different than the Keene pump. The PHP500 Keene pump in the 13 hp configuration runs best with a jet log diameter of approx 28.5mm. Your best best is to buy the jetlog direct from Keene as they come in this size stock.

You can ask Keene to supply you with oversize impellers for this pump which will give you more pressure and some more volume and utilizing the same backing plate and seals. If you do this you can sell your left over stock impeller and pump housing for pretty much the cost of what you pay for oversize impellers (sometimes more) Ask Dan Gerber to order these for you. Ive done this multiple times and its like night and day. Just a thought

thanks for your help cheers