Project ROV & AUV MilosNovember 21 2016
To go out to the Ascension Island and conduct ROV surveys in the shallows & the deep. Accessing the opportunities for the potential use of Remotely Operated Vehicles (ROV’s) in connection with tourism and geological exploration.
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Its looking like it will now be the Greek Island of Milos, looking at the hydrothermal vent systems.
The Venting sites SE of Fyriplaka volcano as well as in Adamas Bay - Airport (1-2 m depth) and Cape Boubarda (60-110 m depth), Palaeochori Bay (0-40 m depth), east of Spathi Point (90-220 m depth), Voudia Bay (10-30 m depth); The hydrothermal discharge (123°C) off shores of volcano with precipitates of Fe oxides, amorphous silica, and native sulfur. "Milos (Hellenic Arc) can be regarded as having 5 separated vent fields: 1. Milos Bay (the central cauldera), 2. N. of the island at the cauldera entrance, 3. Boudia Bay (NE side of island), 4. East of Island (NE of Spathi Point), 5. SE of Island (Palaeochori Bay-Kiriaki Bay)".(Dando PR, et al 1995).
Sad news, we cannot deploy ROV on Ascension...
When going to Ascension you have to apply for a permit be it if on holiday or doing research, this was the last step of the trip going forward. The Uk government has a final say over wether or not certain equipment can be used on the island as contains potentially sensitive material being a large military installation. They denied the use of ROV so there is no point continuing to go there.
However, we are looking for alternatives to the ascension island, places near to hydrothermal vents or subsea volcanos using a google earth plugin at:interridge.org/irvents/maps.
So should still be exciting non the less although the time frame has become delayed and will keep this informed as i know.
The drop device,
The pictures show the drop device, the reason its on here is that the Geevor mine drop was a first practical test of the design. Which is to be hopefully used out in Ascension for Benthic surveys.
The image on the left is the original design by undergraduate students was to place a waterproof camera into the acrylic case and have LED’s attached to a copper ring to provide a heat sink. The whole device was flooded with silicon oil to further cool the LED’s. This was effective in drawing away the heat but however the LED’s were reflecting off the base of the acrylic causing significant glare on the camera lens.
The drop device was redesigned to incorporate separate ‘light pods’ that are totally independent of the main acrylic case. New Independent light pods have been designed to be external from the main body of the device and completely independent systems. The light pods were modified to have a ‘smart’ system in place that will monitor voltage of the batteries and ramp the LED’s as the voltage does. It also contains various safety features such as a battery cut off so not to damage the battery as well as a system to monitor temperature and scale down LED’s if too hot.
Drop Device Test
We dropped the Device down Geevor Tin Mine, formerly North Levant Mine, which is a tin mine in the far west of Cornwall on the north coast, about 8 miles from Land’s End and 18 miles from Penzance in United Kingdom. The mine was operational between 1911 and 1990 during which time it produced about 50,000 tons of black tin. The site has since been converted into a museum and heritage centre.
At Geevor the deepest shaft is the Victory Shaft - sunk vertically to a depth of 1575 feet (480 metres). Work began to sink Victory Shaft in 1919: this was the main shaft at Geevor.
It has been flooded for more than 20 years, and the Geevor curators were keen to find out the status of the timbers since the flooding. The Drop Device was intended to film everything that was in front of it as it was sent down, so once it had been brought back up, the footage could be retrieved.
I have dates now end of November for two weeks, so the Experdition is a go!
we will be looking at subsea geology and video surveys and using this data to produce Photogrammetry 3D models of areas of interest such as subsea structures and shipwrecks.
I'll be taking the fleet of OpenROV and a custom drop device, (which i finally got working)
I am having a meeting next week to determine the dates of the expedition which has been delayed due to the work schedule, preliminary the dates are mid Oct to mid Nov. while out in ascension i will be hopefully be conducting surveys in association with the Ascension Island Conservation group as well as Bristol university and producing 3D reconstructions of marine areas using photogrammetry. Also ariel surveys to produce 3D models of the coastal environments.
Testing on cable feed throughs is all ready to commence once the pressure RIG is repaired.
The light pods i have designed have been built finally. These will attach to a drop device with a simple camera set up inside. The workshop here at bristol has done an excellent job making these, they now require a bit of assembly putting in the LED circuit in.
Wireless Tether Management
The ROV now has WiFi enabled Tether Management System meaning the use of the ethanet port on a computer is no longer needed so we can use netbooks and mobile devices to control the ROV’s. The use of tablets and phones have only limited capacity so far due to software of which an update is due to enable these features but when they do we are all ready to rock & roll.
One of the ROVs had slightly off IMU data but this has been fixed now with a plugin that allows for the data to be zeroed.
The pressure test to 3km (300 bar) the pressure was ramped up from 250 bar to 300 got to 280 BANG!!!! (pressure equalled) the bolts failed and stripped two nuts bare. So new bolts and nuts will need to be sourced but i don’t think 300 bar is achievable on the pressure RIG we are using.
Pressure Testing on Hold
The RIG produced ‘graunching’ noises and squeals and the brass axle support sleeve worked its way out and had to be pushed back in; the grub-screw securing it is ineffective.
I have sent it to the workshop to be dis-assembled to find the cause(s) of the noises and the brass sleeve be modified so that it is constrained by mechanical interference with the grub-screw not contact-pressure friction.
New bolts have been ordered also to replace the ones that stripped and to get stronger bolts.
working on more feedthroughs for different cable types and pressure testing to sam levels as fibre optic were. Dependant on the RIG being fixed.
Drop Down Device Lights
The original design by the undergraduate students was to place a waterproof camera into the acrylic case and have LED’s attached to a copper ring to prove a heat sink. The whole device was flooded with silicon oil to further cool the LED’s.
This was effective in drawing away the heat but however the LED’s were reflecting off the base of the acrylic causing significant glare on the camera lens.
New Independent light pods have been designed to be external from the main body of the device and completely independent systems. These will consist of a battery, resister and the LED.
Pressure testing ROV cable feedthroughs for deep depth beyond the OpenROV limit.. I have tested 150 bar and 200 bar.
Moving onto the overkill of 300 bar which would be roughly equivalent to 3000m or 3km.
The tether currently being tested is for fibre optic cable, which would give the best data transmission at these distances.
300m of standard tether attached to the ROV with no modifications works very well, this will be tested in the marine environment as well.
I have just upped the anti with RS Pro 1 Pair Data Cable 500m this also worked, which is surprising as i read that the home plug range was around 400m.
I am also looking to develop a kind of plug and play mechanism for attaching tethers to the ROV’s and together to make various lengths.
Pressure Testing Feed Throughs
The pressure RIG and the feed through was tested up from 0 bar to 100 bar, the cable and feed through were undamaged and did not let water pass.
This means that for a deep application this type of cable arrangement could be utilised on the camera RIG and possibly future ROV work.
The new liFepo4 batteries i ordered where not quite compatible to the OpenROV system as they didn’t have enough of a lip on them to stack. This was fixed using brass washers, i first fixed them on with sliver paint but this was not strong enough as they broke off when testing in lulworth. They have been soldered on now to make a strong conductive joint.
I now have 4 complete sets of batteries for use in the ROV's. The deep ROV (300m max) runs on lipo 3s batteries.
The drone was in a bad state so it required all new electronics such as ESC's and the flight controller. The drone is now completely working with telemetry which provides data on board the drone can be used to gain all sorts of additional information such as voltage usage, compass heading, motor thrust, but most usefully it can be used to map its GPS and height to produce flight paths. Below a video of it in action.
So i am i need of some financial support for this project, now most of the equipment has already been provided and paid for but what i would really like to get is a decent camera to record and share all of the awesome work I will be doing out in the ascension Islands.
So a bit about me i am currently a master’s student with Plymouth University studying MRes Applied Marine Science, I also have a Degree in Environmental Science & Marine science and have always been fascinated with the marine environment and sharing my love of it. I have been making homegrown ROV's for the last 4 years.
A bit about Ascension: The island itself has only been assessable in the last 15 years to tourism and you are also still required to get a permit to go there so this is a unique opportunity to capture the islands coral reefs and marine ecosystems which are on their way to being protected. Part of my project is outreach and the best way is to continue my blogging but the best way would be to vlog and make videos featuring this amazing environment.
Ideally with any funding i would like to put it towards a GoPro and if by some miracle i achieve that goal, the rest will be donated to a conservation charity.
The fleet has a new edition of a drone provided my Mike Allen of Plymouth Marine Laboratory which has been in the sea of all places. Time to repair and rebuild...
This project is in association with University of Bristol and Ascension Holdings to deliver OpenROV modifications such as the capability to Dive to deeper than the specified 100 m maximum.
Also working with team of engineers to design and produce bespoke components and devices for deep sea exploration such as a Camera RIG for deep sea surveys
The Expedition to Ascension Island to conduct research will be to provide Surveys of the surrounding waters on the atoll at various depths using the fleet of OpenROV.
We have a version 2.8, a 2.6/7/8 hybrid and a version 2.6 modified with lipos batteries and rated for 300m. The camera RIG will be made and mobilised into a ROV of sorts for 1km depth.