How Much Floating Junk Is Really Out There?

Engineering
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My family of 5 boat builders is developing an 18-foot, completely autonomous robot boat for oceanographic data gathering (Our Autonomous Research Canoe). Here’s a photo of our manually-sailed prototype:

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According to news articles we read during our initial concept development for this craft, both our competitors have lost craft at sea and, based on the damage that recovered ones show, had them run over by a larger vessel. As a result, part of our concept is to develop active collision-avoidance systems so our robot boat can dodge stuff instead of running into it.

This is even more important for our boat, because in contrast to the 2-knot top speed of one competitor and the 6-knot top speed of the other, our boat has a top speed somewhere around 18 knots. If she runs into something at top speed we won’t be happy.

Ergo, collision-avoidance system. Although we will have shore-side operators with the ability to over-ride at any point and manually steer, if we can do 95% of the job with automatics it makes the boat more durable. We’re developing some combination of what we call “Active AIS”, with the ability to steer the boat away from AIS contacts; and a LIDAR system for avoiding things in the water that are closer such as drift logs, deadheads, and floating shipping containers that went over the side.

Here’s the point of this post: both these systems are going to be costly to develop (unless you guys know of off-the-shelf systems that already exist, that our research hasn’t turned up). Before investing the time and money, we’d like to get some idea of WHAT is out there, and how MUCH of it there is. We’ve read all the articles about how many containers are lost at sea, and have some idea how much slop there may be in that info. We’ve read all the 'We Hit A Whale And Almost Sank" yacht stories; also every yacht sinking we could find, to see what kind of stuff people run into at sea.

Although I’ve got about 20,000 ocean miles sailing on my boats, I’ve only ever once seen something of concern, and that was a 4-foot diameter deadhead log (floating vertically) going out the Golden Gate. Its end would disappear as the crest of each swell passed, and appear in the troughs between swells. As best I could estimate from how little vertical movement it had, it was likely 50 feet long or longer. What is that, 20 tons of soggy log?

After polling the twenty or so sailor friends I have had over a span of 48 years, one hit something unknown halfway from Hawaii to San Francisco; it tore off his rudder skeg. One hit a juvenile sperm whale halfway from the Galapagos to the Marquesas, no damage to the boat but gave the whale a headache; and one (Steven Callahan) hit something unknown that sank his boat, resulting in him being adrift for 76 days and after being rescued writing the book Adrift.

Of course you guys don’t need to worry about running into stuff, but, if you can please share anecdotes of what you’ve seen personally while at sea, or drift items described to you by persons you trust, those stories will help us decide how much time and money to put into our collision-avoidance systems for our little fiberglass peanut boat.

Thanks in advance,

With Warm Aloha, Tim (Kaimana)

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mid ocean seeing anything was worth the walk/climb to see it. lighter stuff grows barnacles and sinks, anything with air in it eventually goes down. I remember what looked like the skin of a animal or ?something and i’ve heard bridge talk of having hit something (“maybe”) but with over 6-7 years sea days there just wasn’t much in blue water. it was closer to shore where anything was seen.
Though I was in engineering if we hit anything word got around, it wasn’t common.
and if you’re sailing anything the size of what you’re posting it’s hard to say what can happen if you’re going blue water.

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From a small boat perspective, our experience has been that significant objects are rare (and we like it that way!) - with one exception – when the Sargasso weed is on the upswing, huge floating mats of weed have been a real nuisance for us. I’ve only seen this weed on the US SE coast and Bahamas/DR/Virgins, but there might be local varieties you would want a strategy for.

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I would not go on any ocean voyage without radar, ever. You cannot see what radar can. Example; I was on a friends sailing boat in the Caribbean at night. I noticed a ping on the radar which came and went. We weren’t going fast and the sea was calm so we got the spotlights out and looked. It was a 20 foot semi submerged container. Had we no radar we would have likely hit it and sunk.

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On the size of boat you are proposing there is one specific stretch of water to be concerned about: Salish Sea and Inside Passage (WA/BC/AK). The danger here is logs. Think floating telephone poles. In May/June certain stretches of the IP are rife with them, particularly Johnstone Strait and the various passages north of that. Not to be taken lightly. I’ve gotten through Johnstone in certain tides and was surprised by the sheer number of them in sight at one time.

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true, the IP has logs all right !! as for the ‘big stuff’ not having problems in the sargasso, that stuff is to be avoided … think successive cleaning of sea strainers for a few hours though most of it is closer to the surface. all oceans have that stuff that’ll cram the strainers. i hated that.

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Anecdotes?! man, I wok on USACE drift collection vessel , you would not believe how much s-t we pick up daily! Anything, from crashed refrigerators to telegraph poles to relic boats to abandoned buoys and pieces of docks!
p.s. There are drift collection vessels run by USACE in every large American port and bay preventing most of the junk to float out to the oceans.

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Thanks everyone for the contributions!

Frankly, we’re not too worried about running into significant objects, with the exception of floating nets or sargasso weed (kelp on the Left Coast), which can snag a $200k research drone and take it right off your balance sheet.

Going out 1,000-2,000 nm to retrieve an 18-foot boat, depending on where you are in the world, what the season and weather is, and what vessels are available locally for hire, at can easily cost you as much or more than the drone is worth.

Thank you tengineer1 for the comment about radar. I had a 36-mile open antenna Furuno on my 56-foot fish boat, and it was the best; we could see all kinds of stuff on the radar screen long before it became visible. The challenge we’re going to have is linking a radar to the automatic steering system on this 18-foot boat; we’re probably going to have to develop that system ourselves, and no idea what the development costs will be.

For freighterman1, this boat will spend most of its time far offshore in blue water, only transiting coastal areas by the shortest possible route to get it into blue water. It won’t be doing any research in places like the IP; because it’s cheap to do research there with smalller, manually-driven shore-based research vessels. The whole idea of robot drones is that they make far offshore research much more affordable, as compared to a 160-foot research vessel that costs $40,000/day to operate.

For SaltAir, thanks for the Oscar citation; one of the routes we’re looking at is to buy or license something like this, then re-write the code to do what we need it to do.

Again, thanks everyone! With Warm Aloha, Kaimana

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