CH250 SONAR

[Dan.Fuller]

HI Snips,

I have a question regarding the CH250 searchlight SONAR, well maybe a couple questions.

1) While looking at the installation on a friends boat, I noted the hull unit was C181-1, which as far as I can tell is for the CH270? I then went and confirmed that the head unit was a CH250-2? However, it appears that the hull unit should have been a CH254/255? am I missing something? For our application I like the idea of a smaller seachest while having the great output of the CH250 (at 150kHz).

2) The reason we were evaluating the unit is we are contemplating installation of either a 250 or a 270 in our relatively small vessel (28 Bertram) and there are two areas of concern. A) height requirement of the installation, which appears to be about 33" minimum? and Location, as in how for forward can one be mounted? In our case, the deepest part of the hull is about 25% aft of the bow waterline and would appear ideal, but it's also on the planing surface of the hull, is that a problem?

I greatly appreciate any insights you can provide.

Thank you for this consideration!

-Dan

 

[Snips]

Dan,
You are correct, the CH-250 uses either a 254 or 255 hull unit and the CH-270 uses either a 181 or 184. The CH-181 is the long stroke, 350mm. Actually I don't know if is possible to mix the two systems due to the internal make up of the sound domes.

Just so you know, Furuno USA no longer sells the short stroke CH-270 only the long. We both strokes for the CH-250.

A sonar installation on a smaller vessel is always a challenge. If you look through the installation manual on a CH-270 you will see a minimum tube length of 500mm. You could do this if the vessels speed was only 10 knots. Over the years we have learned that on a sport fish vessel that a longer tube equals a more stable the installation. For a CH-270 we recommend a minimum tube length of 24" and 26" for a CH-250. We also recommend a fairing to help deflect the water. Under the Manuals & Documents section for the sonars we have an Installation supplement that describes tubes lengths and fairings. Hull units that are mounted forward can come out of the water when the vessel is at cruising speed. While the sonars were built to take a pounding they weren't designed to have the weight of the vessel crashing down of them. We like to see sonars mounted in the back 1/2 to 1/3 of the vessel.

Snips

 

[Dan.Fuller]

HI Snips,

Thank you for the prompt and concise reply, greatly appreciated! I suspect I must have made a mistake when looking at the hull unit on my friends vessel, as I know for a fact the unit is a 250. From the sounds of it, the 250 is the way to go as we would definitely require a short stroke hull unit and the increased output would be a benefit.

Cheers,
Dan