Replies to post #46279 on Sustainable Green Team Ltd. (SGTM)

[nunaka]

Charlie, Impellers are not difficult to change out and anyone who is half lucid would carry a basic load of spare parts for high wear items. (I'm sure they do) Pressure gauges, flow meters,etc. alert operators to developing problems. Biggest hassle with a dredge is plugging the pipe/hose with rocks. There is usually a classifying grate over the mouth of the hose to prevent this. The biggest challenge is keeping trommels and anything that vibrates or rotates in one piece...much more maintenance intensive than the dredges. Very hard on welds,shafts, seals, bearings and bushings. Self destruct was replaced by the word "on" to save 10 letters and a space.

[small time investor]

Charlie, you're right about the impellers. I hope they were pulled during lay-up during the rainy season. Otherwise they can take a set and lose efficiency. The job is not difficult with the right tool, an impeller puller. You can do the job with a couple of flat head screwdrivers but it's dicey. You can damage the impeller vanes. Any experienced operator will note any significant decrease in flow & shut down the unit & check promptly. Difficulties arise with delay. Then you end up chasing parts of deteriorated blades out of heat exchangers. That takes time to be sure you find all the pieces. If you don't, they can block flow, overheat a motor and damage the head. Repairing that is time consuming & expensive.
As far as debris is concerned a simple screen should protect the inlet hose.
John mentioned pulling a dredge when the water flow & velocity had increased. With the rainy season over a large amount of debris should not present a problem. I'm sure the crew keeps a sharp eye out for the occasional floating log & fends it off if necessary. A couple tires & a fender board slung over each pontoon might not be a bad idea.