Furuno Sonar Flange

Dear Steve, I am following your gear review used on your new boat carefully as I am building 54’steel sail boat (Bruce Roberts). I am interested in the Furuno Sonar that you have recently installed. In your review you are praising Furuno for designing the flange to fit a 6" pipe.

"Furuno’s engineers were thinking ahead here, as the pipe is a standard size, as is the flange."

From what I can determine the standard flange for 6" pipe is not exactly the same as the flange supplied with the sonar.

My questions are:
Did you accept the difference between the two flanges and just bolted them together?
Did you have a metric flange installed instead of 6" one?
Or is there US model of the Sonar that comes with a 6" flange on its housing?

Hi Remek: I think Furuno just makes the single model – for both SAE and Metric countries. As you indicated, the standard 6" schedule 80 pipe and the standard SAE pipe flange matched the bolt pattern of the Furuno CH270 flange. All of which makes the pipe install very simple.

One thing we would do differently, however. You can use quite a long pipe if required to keep the flange above waterline. In our case we came up about 8" (200mm) above max load WL. But in hindsight, it would have been better to come up a couple of feet (60cm). This would allow the sound dome to be raised above the water level when the boat was in storage.

Regards – Steve

Posted by Steve Dashew  (November 16, 2006)

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