Salt Water and Electronics - 5th Bass Strait Voyage

After quickly recovering from the prior launch and recovery on Friday 22/3/2024, the vessel was ready for another launch 11 days later on Thursday 2/4/2024, the 5th voyage on Bass Strait.

Following the prior launch and recovery on the Friday, the compass had been replaced and recalibrated yielding much better accuracy. The aim was specifically to improve the determination of the True wind Direction, which contributed to the failure as discussed in the last post.

Om that Friday night, the vessel had been recovered high and dry on the beach after it had been washed ashore, through the small surf.

There was little damage, but the sail and its electronics would have been submerged in the breaking waves on beach.

It was considered that there were no electronic problems with the Sail, and so the vessel was launched again on Thursday 2/4/2024.

Launch from Torquay 2/4/2024 at 8:15pm, soon after sunset

It sailed well, in the light to moderate conditions for the next 16 hours, and almost 15 miles down the course, at which point it failed to proceed down the course, and to started to drift back toward the launch place.

The conditions at that point were very calm.

The vessel drifted back to the west for 2 days and returned coincidentally almost back to the launch point. 

As the boat approached the shore it was possible to interrogate it using the LORA telemetry, when it was within around 2km of the headland.

It was possible to confirm that most of the components were operational.

However the wing sail had not responded to regular polling, since the time of failure, 2 days earlier.

This implied that the Wing Sail controller had failed.

The vessel was safely brought to shore by swimming out to retrieve it, to avoid it entering the breakers. 

Safely retrieved, and brought to shore before entering the breakers.

It was noted that wing sail servo was not operational, and was in the neutral position.

This suggests that it is likely that the last action performed by the controller was to partially reboot, and center the servo. If it had failed without involving a reboot, the servo would most likely have been set to one side or the other.

The electronics were switched off, and then switched back on again, and the Wing Sail returned to operation.

Later inspection of the Wing Sail controller revealed evidence of corrosion, despite the epoxy coating.

It appears that the epoxy coating was incomplete, and allowed salt water to come in contact with the electronic components.

It is believed that this was the reason for the failure of the Wing Sail controller.

It seems likely that the voyage 11 days earlier, where the Wing Sail would have been submerged in the sea water may have allowed salt to remain in voids or fissures in the epoxy coating.

Whilst dry, the salt would not have had any effect.

 

It seems likely that on the next voyage, the moist atmosphere would allow the salt to affect the circuitry.

Wing Sail Controller showing corrosion - top view

Wing Sail Controller showing corrosion - side view

To address this problem, the Wing Sail controller will be fully potted in epoxy.

A new PCB mount, incorporating a potting box has been 3D printed.

New Wing Sail Controller, located in 3D printed potting box