Survey Vessel Frame

Posted on 29th May 2024  by Tom Green

Read time: 1 minute

THE BRIEF

The client approached Twenty20 Engineering to design and manufacture a frame to safely deploy their hydrographic survey sensors, mounted on poles, into the water from their vessel, ensuring an accurate and repeatable process.

The client had the following specifications for Twenty20 Engineering to work with:

• Frame to have a width of 2215mm from centre to centre of each pole
• Have adjustable mounting blocks for a 2.5″ and 3″ diameter pole
• Poles are to be deployed in a consistent and repeatable location for each survey to prevent calibration issues.
• Be robust and corrosion-resistant while being lightweight, either a single or dual-deployment system.

CHALLENGE

The challenge for this project was to develop a design that would enable a consistent and repeatable deployment method for the pole-mounted hydrographic survey sensors.

The client's top priority for this project was ensuring perfect sensor alignment throughout all stages. Even minor misalignment could compromise the quality of data collected for their end users. Secondary considerations focused on achieving a robust, lightweight, and corrosion-resistant solution.

RESULT

To address the challenge of achieving repeatable deployment, Twenty20 Engineering devised a folded hinged section that rested on a fixed bar, ensuring consistent stopping points for the arm during deployment.

To prevent the arm from moving abruptly due to vessel and wave motion, it was secured with two stainless steel locking pins equipped with springs. This simple system was effective in ensuring repeatable deployment. This system is simple but effective at ensuring a repeatable deployment, time after time.

The second challenge was to use high-strength 5082 aluminium plates and corrosion-resistant A4/316-grade stainless steel fixtures and fittings. To mitigate any risk of galvanic corrosion, HDPE shims and washers were incorporated to prevent direct metal-to-metal contact. Weight reduction was a key consideration, achieved through strategic cutouts that brought the frame's weight down to 28 kg.