Saw something strange at the Port of Houston last week

I was delivering a rebuilt hydraulic pump to a crew working the Houston Ship Channel and watched a cutterhead dredge chew through what looked like solid clay. Then about 20 minutes in they hit a big pocket of sand and slurry started shooting out sideways from the ladder. The operator just throttled up and kept going like nothing was wrong. Anybody else ever have the material change that fast on a job and still keep the pump from cavitating?

2 comments

2 Comments

the_hayden15d ago

That bit about slurry shooting sideways from the ladder is a dead giveaway you've got a blowout, not just cavitation. The trick is to keep the suction inlet buried deep enough that you're pulling from the heavier material surrounding the pocket, not the sand itself. If you can, slow the swing speed way down and bump up your cutterhead RPM to keep that sand feeding slower and more even, otherwise you'll lose prime when the ladder breaks through into open water.

nancybailey15d ago

That thing about a blowout matches what I saw once on the Mississippi. @the_hayden is right though, you gotta adjust quick or you're done. I watched a guy on a similar job lose prime in seconds when the material shifted like that, and it took him hours to get the pump back online.