2: A large concrete sunken block lying near Quay 500 in Cape Town harbour is often used by survey companies as a calibration point.īelieve everything the salesman tells you Well, you can average through your data to get rid of swells, but you also get rid of rocks, sand waves and other pesky anomalies that are hazards to navigation.įig. Survey in dynamic conditions without a MRUĭamn, but those MRUs are expensive! No wonder some clients ask why they can’t just run a moving average through their single beam data to get rid of those pesky swells. He asked me what I thought about his mount. I remember one client taking me proudly to his boat and showing me his multibeam transducer attached on a flange at the bottom of a 15 cm diameter stainless steel pipe. Spend some time and some money, and get a rock-solid multibeam mount. The multibeam head is on the end of a 2,5 cm pole that shimmies back and forth in the water like a schnauzer sticking his head out of the car window at 90 km/h.

There is nothing worse than showing up on a site where the client has spent $250 000 on a multibeam system, MRU, RTK GPS and software only to find out they have slapped together a flimsy multibeam mount. Mount your multibeam transducer on a 2,5 cm aluminum pipe Spend a little extra money and buy a MUX (RS-232-to-Network) or, if you have a notebook with some slots, buy a PCMCIA or PCExpress Serial Card. Small time delays in servicing the USB1.0 stream lead to bad time tagging or gaps in data when buffers overflow. Windows treats USB 1.0 devices with the same respect that one treats a poop in the cat litter box. The next day, I showed up with an RS-232 card, threw the USB device overboard and the system calibrated perfectly in less than an hour. At the end of a lousy day, I looked around the back of the computer and found an RS-232-to-USB 1.0 converter and they were brining the MRU data through it. 1: Spoil heaps in Cape Town harbour of between 5 and 7 m in height.Įarlier this year, I spent a frustrating day trying to patch test a client’s multibeam system.

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