Very true but we as consumers must still know what is the best product for us out there. Keene still sells the triple sluice dredges because they were the best that they ever had. No they're not in the catalog and you have to call for a price but they are still for sale and still the best. The best dredge ever produced was the Promac 8" Triple
promackdredge.jpg Photo by Coochee | Photobucket and it was produced by Promac with Keene as a partner more or less. SO as a buyer it is up to us to know how good is really good enough because there are plenty of marginal products out there. Like with the Proline 4" or the Keene 3 stage 4", they are satisfactory as you stated but there are a lot better products out there. A step up from these 2 would be a true over/under and a step above the over/under is the triple side by sides. Then above that comes the side by sides with dual classification like in the Promac Super 8" Triple pictured above. There have been a lot of satisfactory dealers out there that didn't make it because they were just satisfactory. Keene and Proline have a combination of satisfactory and above satisfactory items and it's up to us as the consumers to know what it is that we are buying. Here's another good article on recovery.
» Double-screen Classification System in Dredging
The fact is, a single level sluice like the Proline has room for improvement, so I improved mine. And I mean I really improved mine because I know my equipment. I run my 4" with a 9hp HP500 pump/Gast compressor maxed out and it was tested by 49er Mike and plenty of other well known dredgers over the years that agree that the simple home made over/under added on to the 4" Proline is a cut above. Would the 4" Keene Deep Water triple be able to match it? It would be close because the added horse power on both dredges puts them over the top of every other satisfactory dredge out there. The only way that my 4" Proline might take it is because of the oversized flare that gives me basically no plug us because of the added pressure brought in by the HP500 pump... but it's really hard to beat any properly tuned triple sluice dredge so it's going to be close either way. I'm sure that you remember the 4" Keene Deep Water Triple, it was the one with a 14" center box. Lots of people ran them as 5's but they were originally the Deep Water 4". The 5's had the 20" center box.