Home > PB21AM-3R Mobile Boat Concrete Placing Boom — 21 m, Boat-Mounted

PB21AM-3R Mobile Boat Concrete Placing Boom — 21 m, Boat-Mounted

The PB21AM-3R Mobile Boat is a concrete placing boom mounted on a vessel, so it can reach work out on the water. Carried on a boat or barge, it travels by river to sites that land-based equipment cannot serve — structures built over a river, or riverbanks with no road for a large placing boom or a truck-mounted boom pump. Once on station, it places concrete over a 21 m radius through a three-arm R-fold boom that slews a full 360°, with an end section that folds back through 220° for tight placing into forms. It is a TRUEMAX specialty product, built for over-water construction that other equipment struggles to reach.

Its main use is producing precast concrete structures over the river: precast bridge beams, bridge piers and columns, freeway barriers and concrete columns, cast on the water close to where they are needed. The boom is assembled from modules that pin together quickly, so it is straightforward to install on the vessel, dismantle and move on. As with every placing boom it does not pump — a separate concrete pump on the vessel or barge feeds it — and it runs on a 380V/50Hz supply with a 7.5 kW motor. It is built and tested at the TRUEMAX factory in Haining to ISO 9001:2015 and CE standards, within a line exported to more than 120 countries.

1. Boat-mounted for water access — Mounted on a vessel, the boom travels by river to reach over-water sites and roadless riverbanks that land-based placing booms and truck-mounted boom pumps cannot get to.

2. Built for over-river precast work — Designed to produce precast concrete structures on the water — bridge beams, piers, columns and freeway barriers — placed where they are needed over the river.

3. 21 m three-arm R-fold boom — Three fully-hydraulic R-fold arms reach a 21 m radius and fold compactly for transport on the vessel.

4. 220° end-section fold — The third arm folds back through 220°, so the hose can tuck in tight to place precisely into precast forms and around obstructions.

5. Full 360° gear slewing — Gear-driven slewing turns the boom a complete circle to serve forms and pours all around the vessel.

6. Modular pin-shaft assembly — Modules connect quickly by pin shafts, making the boom fast to install on the boat, dismantle and relocate between water sites.

7. Radio and cable remote control — Two operating modes — wireless radio and cable remote — let the operator place concrete from the best position on the vessel.

8. Quality components — Hydraulic and electrical parts from well-known international brands for stable, reliable operation on the water, on a 380V/50Hz, 7.5 kW drive.

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Technial Parameters

Item	Unit	PB21AM-3R (Mobile Boat)
Performance
Max. Radius of Placing Boom	m	21
Free-Standing Height (to boom root joint)	m	4.2
Slewing Range	/	360°
Mode of Slewing	/	Gear Slewing
Application Scenario	/	Mobile Boat
Circumstance Temperature	℃	-20 ~ 55
Power Supply (customisable)	/	380V / 50Hz
Boom (3-Section R-Fold)
1st Section — Length	m	8.4
1st Section — Articulation	°	0 ~ 90
2nd Section — Length	m	6.9
2nd Section — Articulation	°	0 ~ 180
3rd Section — Length	m	5.7
3rd Section — Articulation	°	0 ~ 220
Delivery Line
Delivery Pipeline Diameter	mm	Φ125 × 4.5
Delivery Hose Diameter	in × mm	5" × 3000
Power & Hydraulics
Motor Power	kW	7.5
Hydraulic Pressure	MPa	28
Hydraulic Oil (5℃–55℃)	/	HM46 anti-wear
Hydraulic Oil (-20℃–5℃)	/	HM32 anti-wear
Weight
Total Weight (boom unit)	kg	6400
Max. Lifting Unit	kg	5200

Dimensions & Working Range

The working-range diagram shows the 21 m radius swept through 360° from the boom's position on the vessel, with the steep downward reach the 220° end fold gives for placing into forms on the water. Because the unit is boat-mounted, the general arrangement also covers how the boom sits on the deck and how the vessel is positioned and held on station — read the diagram with the vessel and mooring drawings.

Applications

The PB21AM-3R Mobile Boat is built for concreting work out on the water, where the boom must come to the site by river.

Over-river structures

Structures built over a river — where there is no ground to set a placing boom and a truck-mounted pump cannot reach — are served by the boom from the vessel itself.

Precast bridge components on the water

Precast bridge beams, piers and columns can be produced on the water close to the crossing, the boom placing concrete into the forms from the deck.

Roadless riverbanks and waterways

Riverbank sites with no road access are reached by water, so concrete placing is possible where land equipment simply cannot be brought in.

Freeway barriers and concrete columns over water

Freeway barriers, concrete columns and similar elements cast over or beside the water suit a boom that places directly from the vessel.

FAQs

What is a mobile boat placing boom?

It is a concrete placing boom mounted on a boat or barge, so it can be moved by water to job sites that land-based equipment cannot reach. The PB21AM-3R Mobile Boat travels by river to over-water and roadless riverbank sites and places concrete over a 21 m radius from the vessel — a TRUEMAX specialty for marine and over-river construction.

Why use a boat-mounted boom instead of a land placing boom or boom pump?

Access. Some sites have no ground to set a large placing boom and no road for a truck-mounted boom pump — structures over a river, or riverbanks without roads. A boat-mounted boom comes to those sites by water, which is the only practical way to place concrete there.

What can it be used to build?

It is mainly used to produce precast concrete structures over the river — precast bridge beams, bridge piers and columns, freeway barriers and concrete columns — placing concrete into the forms from the vessel close to where the elements are needed.

Is this the same as the formwork-climbing PB21AM-3R?

It is the same 21 m placing-boom model supplied in a different configuration. The Mobile Boat version is mounted on a vessel for over-water work; the formwork-climbing version is mounted on climbing formwork to rise with a wall or core. Same boom and reach, different mounting and application — tell us which your project needs.

Is the placing boom a concrete pump?

No — it places concrete, it does not pump it. A separate concrete pump, carried on the vessel or barge, supplies the concrete, and the PB21AM-3R distributes it through its boom. The two work together on the water.

Is it electric, and how is it operated?

It is electric — a 380V/50Hz supply with a 7.5 kW motor, voltage and frequency customisable — powered from the vessel's supply or a generator. It is operated by wireless radio or cable remote from the deck.

What is supplied, and how is it delivered?

The standard supply is the placing-boom unit with its hydraulic and control system and remote; the boat or barge, mounting, delivery line, hose, spares, installation and commissioning are configured to your project. Tell us your waterway, vessel and the structures to be cast, and we will confirm the configuration and lead time.

Boat-mounted versus land-based placing booms

Most TRUEMAX placing booms work on land — climbing a structure or formwork, standing on outriggers, rolling on a frame, or free-standing on a tower. The PB21AM-3R Mobile Boat is the exception, mounted on a vessel so it can place concrete out on the water. Where a site is over a river or on a roadless bank, no land boom or truck-mounted pump can reach it; the boat-mounted boom comes by water instead. It is a niche but essential tool for marine and over-river construction, and a TRUEMAX specialty.

How the boom works with a pump on the water

On the water the system is the same in principle as on land: a concrete pump feeds the placing boom, which distributes the concrete. The difference is that both ride on the vessel or an accompanying barge, supplied with concrete brought out by boat. The PB21AM-3R takes that concrete and places it into the forms over a 21 m radius, with its 220° end fold reaching down into precast moulds — so a crew can cast bridge components on the water with the same control as on a land pour.

When to choose a mobile boat placing boom

Choose a boat-mounted boom only when the work is genuinely over or beside the water and cannot be reached by land — over-river structures, precast bridge components cast on the water, roadless riverbank sites. For construction on solid ground, a climbing, spider, mobile or tower placing boom is simpler and better matched. The PB21AM-3R Mobile Boat exists for the projects that the others cannot serve, bringing the placing boom to the water itself.