Floater spacing 101: keeping your HDPE main on the surface

The three loads you must carry

Self-weight of the filled pipe, slurry density inside it, and the dynamic wave load that tries to submerge the line. Buoyancy must cover all three with reserve.

A rule of thumb used on our projects: total floater buoyancy ≥ 1.3 × submerged weight of the filled pipe over the same length.

Worked DN 800 example

A filled DN 800 PE100 line carrying 1.25 t/m³ slurry needs roughly 300 kg of net lift per metre of run in sheltered water.

With FLT floaters rated 520 kg each, a pair every 3.5 m keeps the line visibly above water with reserve for a 1 m sea state.

Anchoring

Space anchors at 30–50 m and always terminate the floating train with a flexible section — FRH hose or rubber discharge hose — so the shore transition is never rigid.