3000m Umbilical Buoyancy

Writer： admin Time：2026-08-12 09:54:00 Browse：15℃

Project Overview

A subsea customer in France approached FLOAT X for a customized buoyancy solution for an ROV umbilical operating at depths of up to 3,000 meters.

The customer required approximately 50 kg of total buoyancy and needed the floats to accommodate two different umbilical/cable diameters: 20 mm and 25 mm.

In addition to the deepwater pressure requirement, ease of installation and secure attachment to the umbilical were important considerations for the project.

Customer Requirements

The main requirements included:

• Operating depth: 3,000 m

• Total required buoyancy: approximately 50 kg

• Compatible with Ø20 mm and Ø25 mm cables/umbilicals

• Hinged design for easier installation and removal

• Secure attachment during subsea operation

• Customized in a small batch according to the project requirements

FLOAT X Solution

Based on the operating depth, required buoyancy and cable dimensions, FLOAT X developed a customized deepwater syntactic foam buoyancy solution.

Interchangeable Nylon Inserts for 20 mm and 25 mm Cables

One of the key challenges was that the customer needed the buoyancy floats to work with both 20 mm and 25 mm cable diameters.

Instead of manufacturing two completely different sets of buoyancy floats, FLOAT X proposed using custom-machined nylon inserts.

The main buoyancy body remains the same, while the internal nylon inserts can be selected according to the cable diameter. This provides compatibility with both Ø20 mm and Ø25 mm configurations and gives the customer greater flexibility for different operating requirements.

The nylon inserts also provide a defined interface between the buoyancy module and the cable.

Hinged Design for Easier Installation

The customer requested a hinged buoyancy float so that the modules could be installed around the umbilical without having to feed the cable through the entire float.

FLOAT X designed the buoyancy module as a split-body hinged structure. The float can be opened, positioned around the umbilical and then closed in place.

This design makes offshore handling, installation and removal more convenient, particularly when working with an existing ROV umbilical.

Additional Cable-Tie Fixing

In addition to the hinged structure, cable-tie fixing points were incorporated into the design.

After the buoyancy float is closed around the umbilical, cable ties can be used as an additional securing method. This helps keep the two halves securely closed and provides a simple and practical secondary restraint during handling and operation.

The combination of the hinged structure + nylon inserts + cable-tie fixing provides a straightforward solution that is easy for operators to install while maintaining a secure fit around the umbilical.

Manufacturing and Assembly

The buoyancy modules were manufactured from deepwater syntactic foam suitable for the specified operating depth.

Each module was machined according to the customized design, including the split structure, hinge interfaces, cable-tie locations and internal geometry for the nylon inserts.

Before delivery, the Ø20 mm nylon inserts were pre-installed in the buoyancy modules, allowing the customer to receive the units in a ready-to-use configuration.

Project Result

The completed buoyancy floats provided approximately 100 kg of total buoyancy while meeting the customer's 3,000 m depth requirement and accommodating the required cable sizes.

The final solution combined:

3,000 m deepwater capability + interchangeable Ø20/Ø25 mm nylon inserts + hinged installation + additional cable-tie securing.

The project demonstrates FLOAT X's capability to develop customized subsea buoyancy solutions based not only on buoyancy and operating depth, but also on the practical installation and handling requirements of ROV and umbilical systems.