Just curious if anyone has tried building a hull-cleaning ROV/AUV. I was looking at the few commercial options and they seem to operate motorised brushes, though some use pressure-jets as well.
The problem seems to be with the position holding though, probably modifications to the software to engage vertical thrusters when cleaning when engaged. Capturing bio-contaminants could be a problem for some biosecurity requirements too. You’d require a water quality tester as well from what I could see in the legislation. Any ideas or suggestions of commercially available products for comparison, would be great. Might draw up a spec sheet if I can get some ideas.
I was also thinking this would be a potential AUV as well, because that would eliminate the tether, and it’s always fairly close to the surface.
Cheers
Hi @General_Scipio - great topic as interested in this myself and have researched (extensively!) with the most established products are super heavy industrial hull cleaners that cost $100s of thousands and regularly used on large ships and freighters in combination with divers.
Producers of smaller products for recreational vessels are suprisingly rare and seems to be something of an innovators nightmare as my searches generally end in a graveyard of broken links. As you say most of these typically use some type of motorised brush but the only AUV type I’ve come across is the Hullbot.
After spending some time on this I suspect one reason so many fail is that hull cleaning is a far greater challenge not just the issue of position/orientation holding you refer too but also hull movement, the complex structures found on hulls and the marine environment.
A remotely operated version I’ve used is the Keelcrab - which is quite ‘old school’ in terms of ROV technology but does ‘stick’ to the hull using suction from an impellor, similar to (identical?) to a pool cleaner. This approach largely eliminates the postioning/orientation problem and I think essential for any hull cleaning ROV. In my experience the movement of the hull even in minor wash renders any other hull cleaner useless (but appreciate any counter examples!!!).
Biofouling requirements are a big issue but differ dramatically between various jurisdictions. Here in Australia there are restrictions around 'in water’hull cleaning but think New Zealand has the strictist regulations.
Personally think these restrictions are absurd though given the material is already in the water and any laws that limit in water hull cleaning only serve to reduce cleaning and so increase the biofouling of waterways (but thats just me!).
The major limiting factor is the strength of the abrasion force applied to the hull in water (eg no point in cleaning the hull if you sink the boat in the process). This means you can usually only remove ‘soft fouling’ and most products could not remove ‘hard’ fouling like barnacles in water as just too risky. For this reason the use-case for most hull-cleaning ROVs seems to be light regular cleans only.
Appreciate any links you have to other products as there has to be a better solution out there but not sure anyone has found/invented it yet!!!
Yeah. Saw a couple of comments from people regarding weight as a huge factor. I’m in Australia too so I was looking at regulations. Best option would be a shoreside suction pump and filtration system, but that’s another hose to drag around. Beside that, cleaning options seem to favour cavitation lances, can clean heavy macro fouling with ease and doesn’t damage most antifoul, but that’s a thick high pressure hose that also needs to be dragged around. So they seem to be the biggest drawbacks. ‘Regional’ fouling, ie, most DCV’s and pleasure vessels, doesn’t need to be captured though thankfully, so you may be able to get away with the filtration system only as required.
I don’t know of any commercial products but I read an interesting research paper on attaching a cavitation lance to a manipulator arm for niche cleaning. But that’s getting even more complex.