Voyager 3.0 - First On-water Trial

Its November 2021 and most lockdown restrictions are gone now.
Today was the first opportunity to get on the local lake for the maiden voyage of Voyager 3.0.
It was good to get the boat in the water for the firs time,  but it was inconclusive due to turbulent winds coming through the nearby trees making course keeping difficult.

I need to pick a day on the lake with north-westerly winds to get the cleanest winds for testing.

Voyager 3.0 Approaches First Sailing Trial

September 2021 in Melbourne is still a time of lockdown with restricted travel.

This has allowed time on the weekends to move forward with Voyager 3.0.

The first sail for Voyager 3 is almost complete and almost ready for the water. 

This is the Lake sail, which is intended to be a fairly large sail for lake use, not in the ocean.

It is expected that the Ocean sail will be about 75% of the size of the Lake sail.

The structure of the Lake Sail is complete, awaiting the plastic covering.

 Voyager 2.0 Last Voyage. What happened ?

Voyager 2.0 was at sea for 32 hours before the failures occurred, leaving the boat adrift for a further 44 hours.

The mast was broken off , and the electronic controller was lost.

Voyager 2.0 shortly after recovery

The mast suffered a brittle fracture at deck level.

The image below shows the fracture.

Remainder of Mast showing the brittle fracture at deck level

A test bend was performed on the remaining part of the aluminium mast.

It displayed the typical ductile bend expected of aluminium tubing.

The aluminium mast had been in use for around 3 years. 

The brittle fracture was probably due to work hardening or a fatigue failure.

This failure was avoidable.

Testing of the remainder of the mast showing ductile failure.

The Electronic Voyager Controller was lost when the lashing failed. The lashing was fixed to the hull using a simple 25mm screw through the fibre glass and into the foam. 

This was fine for trials on a lake, but clearly not suitable for ocean conditions.

Failed Lashing intended to restrain the Equipment Compartment 

The Spot GPS and the controller are housed in a Sistema Brilliance 920ml container. After 76 hours at sea, about 5ml of water had entered the container.

This implies that additional sealing will be required if these containers are used at sea. The containers are watertight for short durations, such as lake trials.

Tests will need to be performed to establish the reason for the water ingress. This could include diurnal heating and cooling, improperly seated seal, possibly due to dirt particles, or simple leaking through the seal.

Brilliance 920ml Container with the 5ml water acquired during the 76 hours at sea.

 First and Last Ocean Voyage of Voyager 2.0

May Day 2021, a Saturday, at 6am, Voyager 2.0 commenced its first ocean voyage from a beach at Torquay in western Victoria. The course consisted of seven waypoints covering 55nm through to a beach in Western Port, in eastern Victoria.

The course from Torquay to Pt Leo.

Pre-Launch

Sunrise on May Day with Voyager a few kilometres into the voyage, still in range of the LoRa telemetry.

The winds were light to moderate from the north for the majority of the journey.

She sailed well for 32 hours to the waypoint south of Cape Schanck, a distance of approximately 30nm. Voyager successfully round the waypoint at about 1:40pm on Sunday May 2nd.

Voyager 2.0 sailed well for 32 hours in Bass Strait.

The boat successfully rounded the waypoint, and commenced the beat in the north easterly wind, but within about half an hour there was a catastrophic failure of some type which meant the boat was no longer sailing. 

With good fortune, the winds turned to the south east later that night, at around 20 to 25 knots.

The slow rate of drifting, in strong winds implied that wingsail was not present.

Eventually Voyager drifted with the tides and the south easterly winds into Western Port.

It ultimately drifted in to a beach at Shoreham, where I was able to retrieve it, 44 hours after the failure.

It was an extraordinary coincidence that the beach at Shoreham where the boat drifted ashore was just 3km from the intended destination at Pt Leo. 

Once Voyager was retrieved the nature of the failure became apparent.

The wingsail was missing as expected, but also the main controller was missing. 

This contained the electronics including the SD card recording the sailing data.

It was lucky that the GPS satellite tracking  was not lost, and allowed the remainder of the boat to be retrieved.

The remnants of Voyager on the beach at Shoreham.

Voyager 3.0 Emerges

Voyager 3.0 Design Goals

Voyager 3.0 is next in the series of the Voyager sailing drones.

The main aim for Voyager 3.0 is to be able to operate at sea for about 14 days or longer.

Voyager 2.0 can only operate for about 4 days on battery. Voyager 3.0 will include solar charging with the aim of allowing continuous operation. An endurance of 14 days at sea should allow for a rounding of King Island from the Victorian coast and back.

Tests of solar charging rigs have suggested that around 20 solar cells as a minimum are needed for reasonable charging levels for a 2S battery powering Voyager.

The dimensions of Voyager 3.0 have been entirely dictated by the compromise of minimum size for ease of handling, versus adequate deck space to accommodate enough half-size solar cells to support reasonable charging levels.

Overall dimensions of 1800mm length and 350mm beam were chosen to allow possibly up to 23 half-size solar cells to be accommodated.

Proposed Deck Layout with 23 Cells 

Proposed Layout for Voyager 3.0 along side Voyager 2.0 for comparison

Commence Construction of Voyager 3.0 with the Stringer, shown partially completed here

Preparing to glue the first foam sheet on the stringer.

Part way through cutting the foam sheets using a hotwire cutter.

Commence shaping the laminated foam hull.

Part way through shaping of the foam core hull

Voyager 3.0 with glassing finished, ready for fit-out, along side Voyager 2.0

Note: This is part of the ongoing development of a low cost autonomous oceangoing sailing drones, utilising a self-trimming wingsail. This is the Voyager series of sailing drones.

Another Port Phillip Crossing Attempt - Post COVID Lockdown

Melbourne, Australia has come out of the second lockdown recently, so on December 10 2020, I commenced another run across Port Phillip.

In the months since the last run we've been in lock down for weeks at a time and not permitted to either leave home or leave our local area without good reason.

During this time Voyager 2.0 has had some hardware and software updates based on lessons learnt during the last crossing attempt.

The main software issue being addressed was the method of correcting the course as the vessel is steering toward a distant waypoint.

Checks done. Ready to go again.

 Steering to a Waypoint

When waypoints are only a few hundred metres away, it is simple to steer a course representing the Bearing to Waypoint (BTW) and you will typically arrive there, having followed closely along the rhumb line.

When the waypoint is many miles away, and the steering method is to steer the BTW, then it is quite likely that the vessel will deviate great distances from the rhumb line over a period of time.

This was one of the problems encountered during the last voyage across Port Phillip in March 2020.

The main software design change since then was to continual measure the Cross Track Error  (CTE) and use this to add a proportional course correction to the BTW to encourage the vessel to return to the rhumb line. The amount of course correction to apply is calculated as the ratio of CTE to CTEMax (where CTEMax is defined in the mission as half width of the corridor to the next waypoint), multiplied by gain constant.

Hence the simple course to be steered is: BTW - CTE/CTEMax x Kc

Note: This is all assuming that a course can be laid directly to the waypoint without tacking. If tacking is required, then a whole set of different rules apply which are beyond the scope of this article.

The first 10 hours were good

The vessel sailed from east to west, and for the first 10 hours was perfectly on course, staying very close to the rhumb line.

Unfortunately, at 6am the next morning, it was once again picked up be a fishing boat. A commercial fishing vessel this time.

This can be seen in satellite tracking plots shown in the image below. It was picked up in the middle of Port Phillip, as it was heading eastward, and carried on the remainder of their fishing trip, before the fishing vessel returned to her home port of Port Arlington.  I arranged to meet them there for the handover.

Satellite Tracking Plot 

Shared View: Voyager 2.0 December 2020 - SPOT Tracking (findmespot.com)

Mission in Yellow and actual course in Green. You can hardly separate them

Conclusions

The new method of steering using CTE combined with BTW appears to work well.

I've tried to sail across Port Phillip twice now, and failed both times due to human intervention.

I'll need to add signage suggesting to "KEEP CLEAR" or head out to the open ocean where there's less chance of meeting other vessels.

Port Arlington - Home Port for the last vessel to "rescue" Voyager

This is part of the ongoing development of a low cost autonomous oceangoing sailing drones, utilising a self-trimming wingsail. This is the Voyager series of sailing drones.