The pipe is rarely the problem on a dredge line. Floaters that were sized for an empty pipe, flanges that do not match the dredger, and a discharge end that was ordered in the same wall as the rest of the line — those are the recurring failures.
Floater spacing is a calculation, not a habit
A floater must support the submerged weight of the pipe plus the slurry inside it. That means spacing depends on three things: the pipe diameter, the wall thickness, and the density of what is being pumped.
| What changes | Effect on spacing |
|---|---|
| Larger diameter | Closer spacing — more displaced volume and more slurry mass |
| Higher slurry density | Closer spacing — sand at 1.6 t/m³ is not water |
| Thicker wall | Slightly closer spacing, but adds stiffness |
Send the pipe OD, wall thickness and slurry density and we return a spacing plan. A line that floats when empty and sinks when pumping is a common and expensive mistake.
Sinker sections
Bottom-laid pipe is plain PE with flanges at intervals, and it needs weight — either ballast weights or a thicker wall. On rocky beds, add a wear allowance: the pipe will move, and movement plus rock equals abrasion.
Flanges: get the drawing first
Dredgers are old machines with non-standard flanges more often than not. We drill to DIN, ANSI or your drawing, and we ask for the drawing rather than guess from the model number. A flange that does not fit stops the vessel.
The discharge end wears first
- Velocity is highest at the discharge, so wear is highest there.
- Order one or two spare sections at the higher wall for the discharge run.
- Rotate sections periodically so wear is distributed rather than concentrated.
What we need to quote a dredge line
Dredger type and pump head, discharge diameter and length, floating versus bottom-laid split, slurry density, flange drawing, and deck length for section sizing. With those we return a line build-up: sections, floaters, spacers and spares.