I’m looking at Blueboat to use for sidescan sonar.
I have a Starfish 452f towed unit. Has anyone used Blueboat to tow a sonar, would it have enough thrust? The Starfish is not too big. It looks like I can use Virtualhere to interface USB. I’m just learning softwares. Since I have sonar unit already, I hope I can save a lot of money by not buying Cerulean, plus unit underwater would be more stable if there is chopping seas.
I will also probably interface with Starlink mini for extended com range.
Not quite the same I know, but @bhaley has successfully (all be it with some issues) towed a towfish (in his case it was a Marine Magnetics Magnetometer) behind a Blueboat (Thanks again to @tony-white for helping get the extension up and running)
I have used the Starfish 452f on a number of projects, I think what you are looking at is totally doable but you will have a few other issues to overcome.
I am assuming it is the stock standard starfish version (ie 20m cable) so some insights from Bryan may be helpful (he had 100m of cable for the Mag). Additionally I believe you will have a few software integration things to sort out.
You indicate the use of Virtualhere to interface to the USB on the Starfish Top Box to get the sonar data to have a connection back to a shore base laptop to then (assumed) runing the SSS data collection software (likely Starfish scanline), you would also then need to have the Blueboat via Cockpit (likely) to then give a mirrored GPS NMEA COM stream of the boats GPS so you can feed that into the data collection software. (Likely via Network Telemetry to access the Autopilot parameters, and configure an extra UDP/TCP connection and set up a virtual port) and then Direct Starfish scanline to look at that for the GPS position
I’ve definitely looked at what it would take to interface with that towfish, and if it is indeed just USB on the topside, and the vendor “box” fits within a BlueBoat hull and works with 12-17V DC, then virtualHere is a great option to get started. @Scott_W has the right idea when it comes to getting NMEA out of the system, but I don’t think Cockpit is required for that aspect? It is of course a great option for controlling the system - I can happily say I haven’t used QGC in quite some time.
It may be neat to develop an extension that can log the data coming from the unit locally, so interruptions to your communications don’t lead to gaps in data collection. Starlink will often drop when the vehicle yaws rapidly between survey lines using the default Autopilot parameters, and WiFi is of course more range limited.
As far as towfish operation goes, is the Starfish negative or positively buoyant? I’ve been working on a towfish camera that is similar size, although it uses a long bar along the top of a standard 4"x300mm cylindrical locking enclosure. It is positively buoyant, but uses active control surfaces to achieve adjustable depth. The BlueBoat should have plenty of power to cruise at 1 m/s with the towfish and a 20m cable, but I’ve only been using an 8m length thus far! The biggest improvement I found was disabling pivot turns (set to 0), and setting a large (4-5m) turning radius for the BlueBoat. Between this and setting turn-around distance (based on your tether length/ towfish layback) when planning your survey, you can have the vessel smoothly loop around and get on heading for the next line outside your survey area, and minimize the amount of time the towfish isn’t stable due to lack of tow tension.
Eager to hear how it goes and see the data! I made a small towfish for Cerulean Omniscans with a 2" cylindrical locking enclosure and it certainly helps if the water is choppy to improve data quality! It may also let you get good imagery at deeper bottom depths, as the sonars are closer to it rather than stuck at the surface.
The trickiest part is likely going to be launch and recovery, but if you’re doing that from a boat and not shore I think you’ll manage!
My main concern is if there is enough thrust to pull the fish, sounds like it will, I have 20m and 50m tethers, but where I am now the lagoon depths vary between 30 and 60 meters, so I don’t need to sink down to far. The top box for Starfish is small and runs on 12-16v, so would fit easily in boat. I am now thinking of maybe putting small pc with windows in boat, that way I could just set the thing up to start logging and let it go and Am I correct in thinking, can I access pc with Remote Desktop if have Starlink on board? I’ve never used that function.
This will set up will save me a lot of diesel and I can sit back sipping pina coladas while the data collects
While putting a PC in the boat works (you’ll need an ethernet switch) I tend to strongly discourage it - it can absolutely trash efficiency (using as much power as the BlueBoat does on cruise), and remote desktop is inherently clunky. You can reach BlueOS and drive via Cockpit or QGC via Starlink and Zerotier - more details on that here and here, feel free to ask questions in our discussion thread here.
If your concern is about losing data due to communications issues, logging the (likely proprietary?) data output of the unit may be possible - some reverse engineering could yield an extension that captures (raw) data on the Raspberry Pi running BlueOS without a crazy amount of work, especially in the age of vibe coding!
Are you thinking of setting a fixed length of tether to the towfish?
A few loss of signals is no big deal for me, also maybe with Starlink only when the thing is turning around for the next pass. Even if I get the Cerulean, I would be tempted to rig it as a tow fish, it would be an easier to interface since it set up to go right away….just more $$. Both units use the same or close to the same frequency, so they both have the same range.
I’ll play with tether length, I guessing 3 or 4 meters should do it, the goal will to keep it stable and not bobbing up and down.
These guys are way ahead of me, but I will say I am currently using a 10-meter cable for the Explorer mag. In my case we’re operating in shallow water and have the mag surrounded in pool noodles for flotation in the surfaceand to protect the mag. The thrusters seem to do OK but I’m in the middle of a survey and evaluating the battery life, which may be less than I thought. I did do a test with a 100-meter cable (due to availability) but most of the cable was wrapped on the vessel. It was too heavy to work in anything but a tiny survey. After working with Tony, I think having an app running on the Blue Boat (and not USB to go) is the way to go for more reliable data and without the positioning challenge.
By the way, I am running the Cerulean Ominiscan 450 and I have been pretty impressed with the data quality. I’ve used the Starfish 990 and had problems since it is so light but it is fine if pole mounted. The hull mount of the Omniscan is one reason I think the data is so good on a light and budget system.
Good luck with it! I’d live to hear your results and results of others doing professional marine survey with the Blue Boat.
