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Seawater Sanitation Onboard a Vessel - Vertical Immersion Pumps

Download Case Study

Customer: Shipping Company

Application: Seawater sanitation

Equipment Supplied: 2 x Vertical Immersion Pumps

Location: UK

Equipment supplied 

2 x Azcue VRX Centrifugal Vertical Immersion Pumps c/w Vortex Impellers

  • Application: Sea water sanitation
  • Liquid: Sea Water
  • Flow: 40 m³/hr
  • Total head: 12m
  • Casing: Bronze
  • Impeller: Bronze
  • Shaft: St. Steel
  • S/discharge Ø: DN100
  • Power: 8.6 kW, 440V-III, 60 Hz
  • RPM: 1750 


A UK based marine shipping company were upgrading their sea water sanitation system and contacted us with a requirement for the pumps required. Their current system, used to empty a sump where the sea water and waste solids collected, was over 15 years old and was becoming unreliable. This meant that the engineers on board the ship were spending lots of time maintaining the pump, and they needed a more reliable system to avoid any more problems.

Key challenges:

  • Capable of handling soft solids
  • Able to empty from a relatively deep sump



Castle Pumps have a wealth of experience with marine applications and we were confident that we could offer a more reliable system. We wanted to ascertain all the facts to ensure we selected the most suitable seawater pumps possible; it was important for us to know the sump depth and the maximum size of the solids.

To make the system as reliable as possible, we advised using two pumps in a duty/standby operation to ensure that there was a backup pump in case of any failures. We selected vertical immersion pumps with vortex non-clogging impellers to cope with the soft solids. The pump casings and impellers were specified in bronze to avoid corrosion in the sea water.

These vertically immersed centrifugal pumps can be supplied with various column lengths to fit sumps of any depth like the one the customer had on board. As the pump head is totally immersed in the fluid, it ensures that the pump is always primed and there is no risk of cavitation. Vertical immersion pumps also have the added benefit of the motor being situated above the fluid, which avoids any possible overheating of the motor that arises with the use of fully submersible pumps.

Castle Pumps are fully accredited to enable you to buy with confidence. Our accreditation includes: Our accreditation A division of the CTS Group, Part of Flow Max Ltd.