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Comment by anjel | Hacker News Reader

While gas / electric chainsaws are unlikely to work underwater, I can't imagine a reason why a hydraulic chainsaw wouldn't work on dry ground with its superior weight to power ratio and lack of blue smoky exhaust. Probably quieter too.

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Your intuition was spot on! I used to cut concrete for a living, and we had several hydraulic chainsaws. The torque on those things was incredible. They were quieter than gas chainsaws, even factoring in the diesel-powered hydraulic pump in the trailer nearby. The main drawback, as other commenters mentioned, was portability. The saw itself was shockingly light (which made the torque that much more surprising) and portable - until you ran out of hydraulic line! Plus you always had to watch your lines to make sure they weren't going to get cut by a blade, pinched under a falling piece of concrete, or crushed under some piece of mechanized equipment. Interestingly, there were three lines - hydraulic in, hydraulic out, and a water hose to spray on the cutting surface and keep the dust down. It's been a decade since I worked that job, but I still clearly remember the feeling of revving one of those things up, watching the water fly everywhere, and grinning as I just carved straight into a solid concrete wall - rebar and everything. It was a delight.

I've used one of those to cut a doorway in a concrete wall. Initially I tried doing this using a very large cutting disc but it wore down the disc so fast that it would have required passes from both sides. The saw did the work in a fraction of the time and made a cleaner cut than the disc, which I had not expected. You want to really plan your cuts though, if it should get pinched it probably would be quite impressive.

Thanks for the colorful description! I'm always amazed by the variety of backgrounds of people commenting on HN

I think there's a massive portability difference, plus managing the hoses is a safety issue. I have an electric chainsaw, and always have to keep an eye on where the power cord is.

I've seen what happens when a hydraulic line gets cut in an industrial plant.

For reference, an underwater diver typically has a dedicated hose-manager, a dedicated stand-by diver, and a dedicated job manager watching the vision feeds, the oxygen levels, handling comms, etc.

That's a minimum of four people per job with complex time critical work in harbours holding up transit shipping can see that layered up to cover 24x7 operation.

The hose management is the air mix lines to the diver along with cmms and then any tool lines required - hydraulic, pnuematic, additional electric, etc.

Forestry harvesting equipment (those all-terrain vehicles with long booms) uses hydraulic chainsaws for the felling step. Of course then the hydraulic pump is on the massive vehicle so portable in that way.

https://limbsaw.com/ for a consumer version. Although I don't really get the niche - by the time a branch is high/big enough that you can't use a hand held pole saw, I would think managing the break/fall would be more important.

The chainsaw might be lighter…but the equipment powering it isn’t.

it's not all that easy to generate high quality/consistent high pressure hydraulic pressure quietly either, though.

the early big-dog robots demonstrated that famously.

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