Our field of expertise
Adjustable Winch Beds
G-TEC awarded Saltwater Engineering the contract to design adjustable winch foundations for their Offshore Survey Vessel Karina. The objective was clear, but technically demanding: enable three different winch positions to reach multiple hoisting points on the vessel’s A-frame, without modifying the A-frame itself.
The winches operate within strict spooling angle limitations. Exceeding those angles would lead to uneven spooling, increased wear, and operational risk. Therefore, the foundation had to provide controlled alignment in both the vertical and horizontal plane.
Technical Design of the Winch Foundation
To meet this requirement, we developed a swivel foundation capable of rotation in two axes and mechanically secured in the required position. Because the vertical angles were nearly identical across all three winch locations, Saltwater engineered a single universal swivel unit for use in all positions. This reduced fabrication complexity and increased operational flexibility.
The interface between the swivel and vessel differed per location. The design consisted of two structural base frames:
- A welded angle-bar foundation for the portside position
- A container-bed interface for the center and starboard locations (10ft beds)
By separating the swivel unit from the base frame, the system remains adaptable while respecting the structural limitations of each deck position.
Since G-TEC already worked with Saltwater on designing specific winch bedframes for our chartered vessel in 2023 and being extremely satisfied with the service provided (in terms of technical solutions and time delivery of the studies), we approached Saltwater again late 2023 looking for a technical solution for adjustable geophysical data tow-winches.
The removable and tilting/rotating bedframe installed on 10ft bedframes for our winches has allowed excellent project turnaround during mobilization and demobilization phases throughout 2024 and 2025. Our crew has also rapidly gained experience re-organizing the winches overnight, with virtually no assistance from 3rd parties and no hot-work requirements.
The solution from Saltwater has worked well over the last two years, and will allow us to clear the vessel back deck efficiently.
In short, the collaboration has been excellent.
Karim Makhlouf
MV Karina Party Chief
Specific project data
Project information
Scope of work:
- Load definition and winch reaction analysis
- Structural design of adjustable swivel foundation
- Design of deck interface frames
- Structural verification of local vessel structure
- Fabrication of drawings and documentation
