Marine Ballast Pump

What Is a Marine Ballast Pump?

A marine ballast pump is a sea-water pump that fills and empties a vessel’s ballast tanks, controlling trim, stability and draft for loading, unloading and voyage conditions. Ballast duty is intermittent but demanding: the pump must handle sea water against a wide range of tank levels and heads, and on many vessels it must also prime itself when the tank level falls below the pump inlet.

According to the CTP Pumps marine centrifugal pump selection manual, the series recommended for ballast service covers flow rates up to 450 m³/h, heads up to 150 m, sea-water temperatures up to 80 °C, and suction sizes from DN 40 to DN 250 — operating speeds for both 50 Hz and 60 Hz power systems. Where flooded suction is not available, a self-priming arrangement (gas ejector or vacuum pump unit) is fitted. The full duty tables and technical documentation are available on our downloads page.

Ballast Pump Applications by Vessel Type

Ballast systems differ with the vessel’s trading pattern. Based on the pump arrangements listed in the CTP selection manual for three common vessel types:

Recommended Pump Series for Ballast Duty

CTP does not ask you to pick a model — send the vessel type and duty data, and we recommend the arrangement. For ballast service the starting point is usually the EMC series marine centrifugal pump:

• EMC vertical arrangement — small deck footprint in machinery spaces; rigid motor connection; upper pull-out design keeps overhaul time short at sea or in port.
• Self-priming option — a gas ejector (E) or vacuum pump (N) unit allows the pump to prime when the ballast tank level drops below the pump inlet, a common condition during tank stripping.
• Horizontal alternative — where deck area is free and flooded suction is available, CTP’s horizontal series (interchangeable parts with the EMC) can be matched to the same duty.

See the marine centrifugal pump range for the full specification, sectional view and material table, or ask for selection assistance to match other configurations.

Materials and Shaft Sealing for Sea-Water Ballast

Ballast duty means permanent sea-water service, so wetted parts carry the sea-water material combination from the CTP selection manual:

Recommended Ballast Pump Parts List

Numbered parts of the sectional drawing above, with materials for sea-water ballast duty:

Materials shown for sea-water (S.W.) ballast duty. The pumps are available in other material combinations at request. Source: CTP Pumps.

How to Select a Ballast Pump

Marine ballast pump selection starts from the vessel’s ballast system design, not from a catalogue model. Provide the following and our engineers will recommend the pump, motor and sealing arrangement:

Pay particular attention to NPSH: during tank stripping the available suction head falls, and cavitation risk rises. If you are unsure of the duty data, our pump selection assistance team will work through it with you.

For the wider ship-system context and related pump families, see our marine and shipbuilding pump overview.

Standards and Classification for Ballast Service

Ballast systems are among the most regulated pump duties onboard. Reference points that commonly apply:

• Ballast water management — the IMO Ballast Water Management Convention sets performance and documentation requirements; the pump must work together with the vessel’s treatment system.
• Classification society rules — machinery and pump requirements are published by societies coordinated through IACS, for example DNV, Lloyd’s Register and CCS. Survey and certification can be arranged with the requested society.
• Engineering practice — centrifugal pump design and acceptance commonly reference the ISO 5199 framework, with acceptance testing agreed between buyer and manufacturer.

Tell us the classification society and flag state at enquiry, and we will confirm the applicable certification route.

FAQ: Marine Ballast Pumps

What pump is used for ballast water?

Sea-water centrifugal pumps are the standard choice for ballast transfer. As a marine ballast pump, CTP recommends the vertical EMC-series arrangement where machinery-space deck area is limited, or horizontal arrangements where flooded suction and free floor area are available. The pump must be sized to the vessel’s ballast time requirement.

Does a ballast pump need to be self-priming?

Often yes. When the ballast tank level drops below the pump inlet during stripping, a standard centrifugal pump loses prime. CTP fits a gas ejector (E) or vacuum pump (N) self-priming unit for these duties; if the pump always sits below the lowest tank level with flooded suction, self-priming is not required.

Which materials are used for sea-water ballast service?

Tin bronze casing, casing cover, impeller and seal rings, with a stainless-steel shaft and SiC/SiC mechanical seal faces. Special materials can be specified at order.

How do I get a quotation for a ballast pump?

Send the vessel type, required flow and head, suction conditions, power supply and classification society. You do not need to choose a model — our engineers recommend the pump arrangement against your duty data. Use the contact button below or our pump selection assistance page.

Where can I download the full technical documentation?

Brochures, product flyers and O&M manuals for the CTP marine centrifugal pump range are available on our downloads page. If you need help matching documentation to your ballast duty, our selection assistance team will point you to the right data.

Contact CTP Pumps